Well, but never mind. Thanks for joining us today and nice to see all the locations. I did see somebody put they were from the northeast, so they're doing very well to start with. My name's Gary Parker. I'm head of technical over at the ECA and with us today, we've got Chris and Curtis. Do you want to say hi guys? Chris Edwards Good afternoon, everybody. David Bonner, Ph.D.: Fantastic. We've got a brief presentation for you today about the top 10 ish issues we get on the ECA technical helpline. Now, these are just general issues that we've we've talked about as a team and put together and highlighted between us. Some of the big things that we think industry tends to ask questions about. So we'll run through this today. We can see the chat we can see the questions coming in. We'll have a to answer as many of the questions as we can as we're going if we can't finish them today i'm sure it's pace will be able to send us uh them over and we can pick them up afterwards so with the miracle of modern technology i should be able to press a button and hopefully the slides move on there we go brilliant so what we'll cover today is a bit of an introduction uh about us the the eca and the likes we'll cover off our top 10 questions which the guys are going to uh hopefully respond to we'll summarize it and i believe there was somebody in the chat said do we get cpd for this uh yes if you stay to the end and stay awake so as long as you've done both of those you can scan the screen with your phone and hopefully you should be able to get cpd so a little bit of intro for us uh if you're not sure uh we're the eca uh the electrical contractors association and we do quite a lot for our members and we'll run through some bits today we're mainly going to focus on 7671 i think is right today guys but as an association we don't just look at 7671 we get involved with lots of other uh british standards the emergency lighting requirements fire alarm requirements uh hazardous areas earthen and the likes in fact we've done quite a lot this year with uh fire alarms and emergency lighting and we'll continue to do so so any eca member out there if uh if you do have any questions on other british standards that are related to electro technical do please get in touch and let us know and if we can't answer it we'll often try and find out for you uh will we send slides to people who are attending i don't think we're doing that uh dennis these are uh not going to be sent out i don't believe but curtis pierce can clarify that at the end hopefully for us um okay so straight into the questions with some answers now we'll ask the questions and the uh the the the the guys will pick up the uh the answers hopefully as we're going through if there's anything that you want expanding on just drop in the chat and if we can um so the first one and it does seem that it's slightly heavily weighted in curtis jones's favor this unfortunately so you might hear a lot of him today um earth fault loop impedance curtis um which values do you measure against which ones do you use there's there's 80 100 figures what do you do in terms of validating them yeah okay i think uh you've just added an important bit straight away there with 80 and 100 so that's probably the second half of this question that usually caveats the main question as you can see on screen um so essentially we need to verify against appropriate values so we'll have a look now at what makes uh appropriate values and and assessing different circumstances so initially um you may look at um you may look at is there design information available so maybe you've got a brand new installation uh you've been provided with design data uh you may look to use that to give you a good indication on the suitability of the circuit that you've installed so that would give you an indication because it would take into consideration obviously the length of the circuit uh size of the conductors and so on um it may be that man uh uh you use manufacturer's data so within appendix three of bs7671 uh it recommends uh a preference towards using manufacturer's specific data uh with regards to the actual protective device that you've selected um of course uh opposed to using uh the general route values within bs7671 chapter 41 that most people use so obviously the advantage with using manufacturer's specific data um these values um these values um these values can be less onerous um and the values we see within chapter 41 um and that may bring some benefits in terms of i've spoke with some of our members in the past where they're having to push some other circuits to full limits and full constraints and that and they rely on using manufacturer's specific data which gives that little bit more flexibility so you may in some cases let's use that but yeah getting to the the nuts and crannies of the question i guess the 80 percent which is generally what caveats the question now we need to consider the differences between these values other than obviously 20 percent and it's around temperature um so the 100 values that we find within bs7671 they're based on conductors being at maximum operating temperature so typically for that we apply 70 degrees generally um at the maximum operating temperature uh as maximum operating temperature uh and of course for conductors to be up at that operating temperature um we're looking at the the circuit to be under um load of course uh and those conductors to be running at their maximum current carrying capacity for said installation conditions now often you know that isn't the case isn't where we measure health loop impedance often the conductors aren't at operating temperature and often ideally not um and often ideally not um so more often than not um inspectors will use the 80 percent values which are available to us in various guidance documents typically iet on-site guide iet guidance note 3 so on and of course these are based on a set ambient temperature uh and that's uh as per appendix 3 of bs7671 so often known as zs measured zs measured values um but i think with this as always you've got to consider the conditions so there isn't a blanket answer for this often 80 percent is fine to use but you need to consider the conditions because for example um i mentioned initial verification let's say you've got a very simple circuit brand new circuit you've carried out zed test you've got your r1 r2 values you may calculate the zs on the simple circuit like that uh uh it may be that you've measured the zs but generally if it's initial verification those conductors are going to be at ambient temperature they're not going to have been under load so you're going to be using 80 percent values um but where we change the circumstance and maybe you're carrying out periodic inspection testing and producing an ERCR uh it may be due to the operational parameters of the installation that you're particularly carrying out earth loop impedance testing to verify ads um and ads um and it may be the within a functioning installation you've arranged to temporarily shut down a piece of equipment just to allow you to carry out the test to to verify ads for that circuit of course if you shut down a piece of equipment that's just been operating it's maybe been running under full load uh at or near the current carrying capacity of the cable those conductors are going to be hot um and they could well be at that 70 degree mark so in that case it may be more appropriate to apply and verify against 100 values within BS 7671 so it all comes to placing you know that engineering judgment as always so i think often people use the 80 percent but you just need to be careful of applying always a blanket approach of 80 percent because it could catch you out one or two times maybe saying something's unsafe where you haven't actually considered uh the the parameters and the conditions that you're assessing and of course i guess i guess the caveat of this is obviously you need to record uh values uh that you that you've used on uh your certificate generally we record the values as per BS 7671 you don't have to it might be as i said using manufacturer specific data so you just need to pay reference to that's what you've used and obviously attach it with your certification so that's sort of the i guess the first question and just on this topic of uh thought loop impedance you'll notice we got a little technical tuesdays icon at the bottom of this uh slide we have done uh a more in-depth presentation on this topic covering sort of all things of loop impedance so um remember it's free to check that out and we may find it on our inca youtube channel so yeah lovely thanks curtis um i suppose a couple of things for the guys at home first uh pete austin put a comment about staying away uh so i'll make sure he's awake so i'll make sure he is awake and uh he gets his cpd at the end so i'll ask you loads of questions pete as we're going through this uh secondly i have told my 12 year old not to come in the room so within seven or eight minutes guarantee you'll see somebody walking in there apologies if he does um and for curtis jones there it's uh i think there was a bit of a lag on the screen so as you were talking the mouth was moving at a different speed so it was a bit like enter the dragon for those who remember that one hey up pete you're still there good um on the screen there kirkus we've got a picture of a is it sonel tester it is a sonel tester yeah it's where probably where they used yeah that's more in reference to probably the final point i made where we have got a more in-depth presentation and we've also put a guidance note together on the topic of earth loop impedance i guess another query we've had through to our helpline and we do get a lot and we do get very different ones i would say the things we're covering today are probably more the common and simple ones um but yeah uh another theory we've had around earth loop impedances um where you are measuring it where the impedance values are very low and the fault current levels are very high um so something we expanded on in that presentation and that guidance note is that a typical off -the-shelf sort of multifunctional test instrument you might not be able to um measure um measure real low values of earth loop impedance where you've got real high levels of fault current and in some cases you can require specialist equipment um you know i know a lot of our members work in large scope installations uh private supplies things like that so um yeah that is a high resolution earth fault loop impedance tester high fault current um yeah fancy test meter and not too much ramble with it uh fancy test meter for specialist locations i'm guessing uh paul i'm not that lucky mate i'm sorry they won't they won't be bursting in uh unfortunately uh okay next slide um i think this is off for chris is it chris this one rcds is this you it is indeed me good afternoon everybody so the question is uh can we use an rcd for fault protection and of course the answer is yes normally under normal situations what we tend to use is either a fuse or a circuit breaker of course to to provide fault protection and when we're doing so we verify our ads our automatic disconnection um against the tables in the regulations normally table 41.2 or 41 .3 and we go along the column we select our breaker and we make sure that when we're doing our test testing that our zs is under that figure there and then we know by and large that we would meet the requirements for disconnection but the question is what happens if we can't meet those times if when we measure our zs is it's too large when we compare it to that table so the question is can we use in that situation an rcd for fault protection and of course the answer is yes if you think about it this is something that we very commonly do with tt we just normally we don't really think about it we know for a tt we provide a an rcd for fault protection we can't just use an rcd per se though we also need a protective device for overcurrent we can't just solely have an rcd in this situation and that's for tn or tt but whilst it may be the default selection and process for tt the same process applies for a tm for instance we may have a really long circuit environment whereby we just can't meet those disconnection times. So we can, in that situation, refer to or use an RCD for fault protection. There are a couple of regulations normally found in Chapter 41 that refer to that, and that's 411.5.2 and 411.4.5. Now, if we're going to do this, though, there is another table that we do need to refer to, and this is Table 41.5. And those of you will probably be familiar, or most of you on the call will be familiar with that table. But the interesting thing about that table, you have a number of options. You have a 30 milliamp RCD, 100 milliamp, 300 milliamp, an S-type. Indeed, that's the interesting point. In other words, you can use all these types of RCD for fault protection. You're not necessarily just restricted to 30 milliamp, or of course you would be if you were providing additional protection. So it's Table 41.5. It gives us a certain values that we need to comply with, and as long as our ZS value that we measure is less than the values in that table, then we are deemed to meet the requirements for disconnection with regard to RCDs. Now, there is one final point, though, I do wish to cover before we move on, and it's a really important point, is that whilst we can do this, if our ZSs are too high, or higher than those allowed in the tables that we've just previously mentioned, what we can't do, of course, is use an RCD just to mask a fault. And what I mean by that is, if, for instance, you are, it doesn't really matter what sort of environment you're in, but if you're testing a circuit, and you have an unusually high ZS, for instance, you may be expecting, I don't know, say, similar circuits, you get 3 ohms, or 5 ohms, or 10 ohms, or whatever it might be. And on this particular one, you've got 50 ohms, and you think, don't worry, I've got an RCD. Well, clearly there's a fault on that circuit, and we must, and we are not allowed to just use an RCD to mask a fault. Clearly there's a fault on that circuit that we need to investigate. But to come back to the question, can you use an RCD for fault protection? Yes, you can, in TT and TN systems. Brilliant. Cheers, Chris. Steve Webster in the chat has just put in, what's the maximum, ZS on a TT, and I guess that was covered in your comment about tables 41. Yeah, no, thank you. It is, it depends on what sort of RCD you're using, Steve, but it's table 41.5, and I can tell you the page very quickly, if, would I be on that? It's, no, I'm not on the right page. It's table 41.5, anyway, around about, page I'm very close, now if you're better with me, page 70, page 70. Page 70. Perfect. Fantastic. Thanks, Chris. Right, next one, moving on then, because we've got a fair few more to go through. Bonding. To bond or not to bond. Chris, is this you again? It is, yeah, this is me again. Sorry, folks. Yeah, now, this is a bit of a bizarre one, and on face value, bonding or verification of bonding or trying to establish whether you need to bond should be easy. But in many situations, it's not the case. And when I say easy, oh, you've just taken the slide away. When I say easy, I mean, look, there are a number of circumstances or a number of items that would need to be bonded. What I mean is it's got to be an extraneous conductive part. And there are three requirements, as you can see on the screen here. So it needs to be conductive. First of all, it needs to be liable to introduce a potential, generally an earth potential. And what we mean by this situation is, is generally an earth potential is given to be zero. Zero volts potential. And it's not forming part of the electrical installation. Now, there's a regulation that gives us some lovely details or some lovely examples, 411.3.1.2. And it's the things that we're all familiar with. It's things like metallic water pipes, metallic gas pipes, that sort of thing normally. Now, don't forget, I'll come back to the middle point there, earth potential. So what this normally means is at some point, it's buried in the ground or it comes out of the ground or it's in fortuitous contact. Contact with the ground. Now, when I said it should be easy to establish that in a domestic sort of environment, potentially it should be easy because you should be able to verify this with a visual inspection. So you would go around tracing it in an ideal world. Of course, I do get that. You trace this pipe when it comes into your property. And first of all, does it come in in plastic or is it copper? And does it go into the ground? So there are your two things really straight away. Is it conductive? And is it buried in the ground? So if that's the case, you could normally then assume that that would need bonding. So you would go around the property and establish what the items need to be. But I'm very well aware that in the real world, sometimes it's not quite as simple as that. For instance, you need to have your danger radar up in many situations. You know, just because a pipe may not come out of the ground or you can't see it, you know, there's quite often in the case, isn't it where a gas pipe, for instance, would be around the front of a house. And I've seen it on numerous occasions where the earth bank is then pushed up against that gas pipe. Now, suddenly that is in fortuitous contact with earth. It's that sort of thing. It's just being aware of what we're talking about here in the potential issues. But there is also a test you can do. Now, the details are in guidance note eight. But if you just go to the next slide, slide, please. Now, this is trying to establish whether something needs to be bonded or not. So what you would do is the three caveats straight away, isn't it? Is it metallic? Can you touch it? Does it got earth potential? And does it not form part of the electrical installation? So if you tick those boxes, and you don't know whether it really needs to be bonded or not, there is this test that you can do. Now, what you would do, obviously, you need to do a Wanderlead test because you need to basically have the probe of your test meter on the item that you're wondering whether it needs bonding, and the other end needs to be on the MET of the installation. And what we're looking for, we're measuring the continuity test. Now, before you conduct this test, you've got a choice of which value to use. Now, the values, as you can see on the screen here, A, B, and C, are all to do with touch potential. So these milliamp figures on the screen here are nothing to do with RCDs. They're all to do with the passage of current through the body, and therefore the potential shock should you be touching that piece of copper and something else. So that's what we're talking about here. And guidance note 8 on the screen, as you can see, gives you three options. And the three options are 0.5 milliamps, 10 milliamps, and 30 milliamps. Each come with their different consequences. Obviously, the larger the current that's going through the body, i.e. the 30 milliamps, the larger the effect on the person who's likely to be touching it. Normally, and I'm saying normally, you do have an option, but normally, when people are conducting this test, they choose the middle value. It's the 10 milliamps, because that's normally the, well, as you can see on the screen, it's the threshold of let go. What that means is, if you're likely to be touching that piece of copper, or whatever it might be, and there's a fault goes through, that you are likely to be touching that you are likely to be able to let go of it, and therefore, no serious consequences will happen. In order for that fault current to pass through the body, we're looking for an homage on our test of 22 ,000 ohms. Now, that's a big number, and there are two ways you can do that test. You can either do it for a continuity test, or you can actually do an insulation resistance test. The principle is pretty much the same. But the measurements are not, of course. And this is the thing that I need to draw your attention to. It's at the bottom of the screen here. If you're doing a continuity test, it's 22,000 ohms. That's a big figure. We need to just be sure that our measurement or our meter is going to be accurate when it's trying to display that sort of value. Or indeed, if we're doing the insulation resistance test, it's the opposite, isn't it? We're talking about 0.02 of a megaohm or 2.2. But it's like you're getting down to very low figures there. We need to make sure that our measurements or instruments are going to be accurate. Anyway, these are the limits that you can apply when you're doing your test. If, for instance, you choose the middle one, you're looking for 22,000 ohms, anything above 22,000 ohms, you don't need to bond it. Because in theory, if you're touching it, the resistance is too great and you're not going to get a sufficient fault path through your body. If the resistance is lower than that 22 ,000 ohms when you're doing that test, then you might need to bond it. In theory or in practice, I do appreciate that this may be difficult. It's all very well on a new installation, but there are some caveats with this because, of course, if you're doing it, you need to make sure you haven't got any fortuitous connections on the item that you are trying to test. But that is one option available to you and all the details there are in Guidance Note 8. Thanks, Chris. We've got a lot of technology to the design stage, which is the design stage in the design stage and saved quite a lot of problems further on. Incorporate in this new technology, the low carbon tech can have issues on some systems, can't it? Chris, I think it's one that's often overlooked and some don't even realise this requirement exists. I think if you catch it early at the design stage, especially on a new installation this isn't a problem um can be tricky on existing installations you know adding either batteries retrofitting and so on um but yeah right basically let's have a look at the requirement so regulation 551.7.2 in depth five it brings around these additional requirements where we're adding generating sets that may operate in parallel with other sources and as gary pointed out there in the question we're typically looking at solar pv or and or battery storage systems uh in parallel with the network supply um so it gives us this formula uh ina which is the rated current of the assembler so a set value that would be provided by the assembly manufacturer that needs to be greater than or equal to in which is the rated current or current setting maybe an adjustable device uh of the incoming circuit over current protected device whether that's either incorporated within the low voltage switch gear itself so maybe a main lv panel uh or upstream of it so maybe in a typical domestic example like we're going to do now um plus um plus the ig which is the rated output current of the generating set or sets where you have multiple so putting a very basic example together just looking at the image to the right hand side of the screen here uh an image we kindly borrowed from our friends over at the iet um so we have um a typical let's say domestic style consumer unit which would have often an ina rating of 100 amps uh a dino cutout fuse of 100 amps in this example and then a typical g98 pv inverter with an output current of 16 amps now of course putting that into the formula um and if gary could please flip to the next slide um it doesn't add up does it um um because we have a little bit more to the right hand side of the right hand side of the screen here um because we have got 116 amps which is greater than the ina value so that's no good um now there are multiple ways to solve this problem and just to be clear this is just some this is one simple example uh i'll allude to maybe one or two more but i'm cautious that i don't spend ages on this um now we've got one potential uh solution to the right hand side of the screen here now firstly looking at this what what this is all about it's it's basically protecting the enclosure the switchgear itself against overload so just like we do with cables we protect them against overload looking at the switchgear itself here protect being protected against overload so looking at one possible solution to the problem we've created on the left you could split the supply at the origin after the you know cut out the right hand side of the switchgear itself and take a dedicated connection point or a small enclosure for the pv then fit an additional overcurrent um protective device so as can be seen that's added above uh the consuming nick now on the screen so essentially this additional overcurrent protective device will provide the overload protection to that enclosure so that's potentially one way um to solve the problem uh to solve the problem uh i know again sticking with the sort of small scale stuff for now um the some manufacturers are providing solutions themselves um so some manufacturers will state that if you arrange the protective devices in a certain way um as per the manufacturer's literature the ima rating may increase say to 116 amps uh so that manufacturers may provide a solution and again you might want to look to append the appropriate manufacturers uh within your handover documentation um but yeah i think at the minute it's very much a small scale basic example which is probably the best way to illustrate this problem but this issue here it doesn't just stick with the small scale stuff it very much applies to larger commercial industrial installations um that essentially will require higher rated uh switchboards uh switchboards uh switchboards uh switchboards and lv panels um when you're carrying out the design um so you know if you you've got a large supply system and you you're having a an lv panel manufacturer for a new installation this needs to be taken into consideration and we've been out and we spoke to some panel manufacturers and for them it's not an issue as long as it's communicated as the uh a part of the design uh switchboards um so there's a few examples there are more we could look at total connected load and if you can't exceed total connected load then you know you may look to depart even um providing appropriate provisions are put in place um but yeah i don't want to sort of bang on too much with this one because i appreciate it's quite a big topic but it's something to certainly consider um yeah brilliant um yeah brilliant thanks um just a question in the chat uh where is it gone uh roger uh talked about the design current but you highlighted this is in relation to war the lord rather than uh design current and somebody mentioned uh devices in series was that i think how would you achieve selectivity yeah there with two 100 amp devices um anything on that curtis you're on mute oh somebody keeps putting me on mute yeah there we go um selectivity really isn't a consideration in something like that because whatever happens you you're going to lose your supply aren't you so for me selectivity wouldn't be a concern in this circumstance whichever of those devices go you lose your supply don't you so brilliant thanks so selectivity um only when necessary i must say having the ability to put somebody on mute in real life would be absolutely wonderful um is this this is also you as well curtis isn't it uh fault current i suppose this links similar into uh the the zs values we were talking about earlier doesn't it yeah um yeah i get all the uh complicated wrong ones i think um so yeah i think you volunteered for them all is is true yeah okay so yeah right looking at the question and trying to tackle this one simpler so can the perspective fault current exceed the rated short circuit capacity of a protective device now typically as we all do we look to when we select a protective device we look to ensure that it is rated for the maximum fault current that it could be um subject to however however however there are circumstances particularly in larger installations and again we have this conversation quite a bit with members where the fault current levels may exceed the short circuit ratings of the protective device so this does happen and it isn't always a problem so in short in some cases yes the fault current levels can exceed the rate of short circuit capacity of the protective device now this in order to do this uh this uh uh you uh you have to utilize um applying uh protective measures um so known as backup protection or maybe otherwise known as cascading so this is mentioned and discussed within regulation 434.5.1 so this regulation uh allows a device to have a lower braking capacitor if an upstream device or devices could be multiple has the necessary short circuit braking capacitor and it is coordinated appropriately so that the level of uh let through energy can be safely with stood by the downstream device so essentially it's looking at the upstream device providing uh um current limited effects um current limited effects and providing uh a coordinated protection now this isn't sort of a general pick it up go and we can just quickly look at this and know that we're achieving these measures so sticking with sort of a larger scope example because this is where it's more often than not applied um in order to confirm that you are achieving uh adequate backup protection applying these cascading measures um applying these cascading measures um it's going to require some level of stutter so often the best way to do this is with use of software um so software will allow you to carry out the necessary stutter it will allow you to look at coordinate coordinating multiple protective devices and where your fault currents are higher looking at these uh cascading effects and looking to see if you can achieve these current needs and effects you could do it via a desktop um could be that you could be putting molded case circuit breakers at the origin of the installation that can deal with these low large fault currents and then it gives you the facility to use sort of standard circuit breakers from that point subject to the design um and they're obviously cheaper and easy devices to go and replace as part of the maintenance regime as a required so one thing that's important here um of course is the device devices need to be coordinated so you're not really going to be mixing brands with this because you're going to be using this because you're going to be using this because you're going to be using this because you're going to need to assess these fault current levels and so you're generally going to be applying this with a manufacturing so as we can see this is part of a bigger topic and I'm currently working on getting a presentation together with um uh let's take a commercial associate of the cascading measures um and and and we will break down and and look at some bigger examples and some physical examples for this because this is a presentation in its own right um one final point on this um consumer units to bscn 61439-3 um i'm sure a lot of us are familiar with that uh they are the typical consumer units that are perceived in domestic and similar installations uh they're those consumer units that are intended for use by ordinary persons um otherwise known as dvo's within 61439-3 now if you have a consumer unit that meets that standard and it includes the additional 16ka conditional short circuit test as described in annex zb or annex diger either or because there's yeah there's sort of two standards running at that minute and then the devices can be taken to be suitable for 16ka this is on the parameters that the nominal voltage is up to two 50 volts ac so we're looking at the single phase and the main fuse is up to 100 amps and either bsc88-3 or the old 1361 type 2 device uh and then the devices within the enclosure are those as specified by the manufacturer so we're looking at here typical say domestic installation where you may have six or 10ka devices within one of these kinds of enclosures that the manufacturer has carried out the relevant and conditional short circuit testing based on these parameters based on either 88-3 or 1361 fuse up front and they've looked at this coordinated protection and verified that it's suitable up to those fulcrum levels so that's maybe a common example of where it would be applied maybe the smooth scale system magic thank you curtis uh we we we do have a comment in the chat uh peter said this is good he said this is good he said other things but we'll just focus on the this is good bit so thanks peter yeah so i appreciate that that one is it's a very it's not quick to answer so we will cover that for eca members anyway in more detail in the future that's all right peter's also based in uganda as well so we've got venezuela and uganda and birmingham all in uh in uh in one virtual room fantastic right moving on um getting on the 20 to 5 um this one uh this is good i'm gonna uh in one virtual room um this one uh i think this has got your name down as well curtis sorry about this what needs to be confirmed prior to carrying out additions and alterations so you're walking into a building you're gonna start doing some work do you just walk in blind or is it worth doing some pre -checks beforehand yeah that that's the important bit here it's it's not going in blind i mean a common example what people do and we know people do they walk in the price of the db change the first thing they do is walk in isolate hopefully uh and rip the board off the wall but all of a sudden then once you've committed to that you may have inherited some potential issues so regulation 132.16 of bs 7671 it covers additions and alterations uh and there's various things now i'm not going to detail it all but we've got to look at existing uh equipment including that of the uh distribution uh it needs to be appropriately rated and key ones are earthing and bonding and they need to be suitable uh if necessary to the protective measure so prior to committing to putting a new circuit in changing a board you need to carry out some form of verification um now that can be done by certain checks or it could be done by an eicr in some circumstances um but the important thing is that some form of assessment is being carried out so before you go and commit to doing the works you've carried out these necessary checks and the fundamentals are there for the safety of the existing installation so you can carry out your addition and alteration and we appreciate this isn't always straightforward and you'll probably notice some of the things we're raising here the often the most difficult when we do additions and alterations applying the bs 7671 for additions and alterations can be difficult um so it's about doing everything you can um and obtaining the relevant information and planning ahead to carry out these necessary checks now of course i'm not saying you need to check the whole installation when you produce an electrical installation certificate you need to detail um the extent of the extent of the installation covered so it's it's down to what is relevant to your addition and alteration but there needs to be some form of basic checks carried out um and of course anything that you do notice uh on top of that that that doesn't affect safety of your addition um you would also note on the certification comments brilliant thank you um there's a very long question in the chat which i'll i'll i'll i'll put a joke in there john about yes i think it's related to a an old f1 driver uh was it kimmy reichner uh you used to get long questions and then answer with just yes or no i'll put a proper answer in there in a second for you right moving on there let's have a look um oh somebody did ask about selecting creativity earlier and this is uh to the creativity earlier and this is uh similar in that sense chris this one's got your name on it i think has it it has indeed well done kurt there was some there were some hefty questions there you dealt with and time for you to put your feet up for a second now um yeah okay so how do i coordinate multiple rcds in series right this is a bit like some of the the topics that kurt's just tried to tackle in theory it's quite easy in practice it may not be particularly with the size of the installation and there are many many items that we need to consider so the first advice really is to take a holistic view of the entire installation what i mean by that obviously is just take a step back and look where we are potentially going to be installing the rcd with regard to where that sits in the installation there are so many things to consider now with rcds and also you know well not least of which is what the rcd is going to be for is it going to be for additional protection is it going to be for fault protection but anyway coming back to this diagram here that we've got on screen so this is what i mean when we say holistic because by and large now everything or most things will have an rcd on them but if we are slapping say for instance an f type or type f or type b rcd downstream of lesser rcds and what i mean by that of course we're all fully aware of the different types of rcds now that they've been introduced into our environment and there's essentially a hierarchy of these devices the ac obviously sits at the bottom we've got the a then the f and the b and the b plus etc etc hence a hierarchy but the point is and i'm hoping you can make out with this this uh image on screen here that's been ripped from uh from a beamer guide with their permission of course um as you can see here on the left hand side of the diagram we've got an ac rcd downstream of a type a now that's fine but we can't do it the other way around we can't do it the other way around because we need to be aware of the limitations of the devices upstream and the potential issues that we're going to be introducing with our equipment potentially that needs protecting via this higher hierarchy rcd for instance if you have a piece of equipment that you are going to install a type b rcd on and within that circuit at source or within the distribution board upstream of the that there is an a type now there are numerous issues with rcds that have come to light and we haven't really got time to go into them all here but there's talks about frequency earth leakage currents all having problems we well aware hopefully that ac type rcds have got a blinding issue um they are still suitable in certain situations but for many situations they are potentially not there are there are loads of youtube videos of the blinding and i am learning so we that in the down and if you're going to climb to the bottom of the bottom of the screen i am now that maybe there is certainly an issue and i won't really go into that but the point is that we need to take a step back and think okay i'm going to put a b type on here for instance what is the situation what's upstream and i need to consider that because by introducing that item of equipment down here the b type is fine because it is rated for that scenario but we're introducing now um additional elements into the circuitry which are upstream devices not might not be with or may cause problems. And of course, if we're, for instance, blind in an upstream RCD and we're using the RCD for fault as well as additional protection, then we've got a big problem. But it's not just as simple as that. There are other items that we need to consider when we're installing our RCDs. For instance, Amendment 3, the bi-directional possibility for certain bits of kit, we need to have bi-directional RCDs. For generating sets, they need to be double pole. We also need to consider unwanted tripping, Regulation 531.3.2, not just nuisance tripping, but the potential earth leakage we're introducing downstream of that device and the magnitude of that. And then, of course, selectivity, 536 area, we need to consider. The rating of the RCD downstream compared with upstream, the type of RCD, generally speaking, and it may not be as simple as this, but it is if you've got two. Recognized selectivity would be if you have an S-type device, say, for instance, 100 milliamp upstream in the downstream one would be 30 milliamps. The three to one scenario is normally considered to achieve most elements of selectivity. But, of course, that's all very well if you've only got two. If you've got more than two, then we need to really start looking at how we're going to split up the installation and how we're going to introduce items. And even potentially, would you believe we need to look at voltage classification as well? That may be an issue with some of the new inverter technologies that we're looking at. So, in a nutshell, our environment is becoming very complex. We're embracing lots of modern technology, but we need to be okay. We need to be aware of the potentials when we're looking, when we're introducing these items of equipment into historic. It's not so much of a problem, hopefully, new build, but certainly retrofit. That's when our problems are going to arise. And we need to just literally take a step back and do a survey. Note what we've got, where it is, how our item is going to affect it. But it's a huge subject, and I hope I've just covered some pertinent points there for you. No, thanks, Chris. As you say, this is taken from a very good Beamer guide, which shows some different types of RCDs. I guess what you're saying here is, 20 years ago, you put an RCD in. Now there's lots of RCD types and variants to consider. Don't just go down the trap of sticking an RCD in. Make sure it's the right one in the right situation, because there is a cost difference between an AC and a B and an F and an A. So, it can come back and call problems further down the line, not just financial, but technical issues as well, can't it? Absolutely. And you're quite right. It's literally just looking up, assessing what's in front of you. You can't just slap in just for your circuit and run off, because you may have implications on the wider installation. Brilliant. Right. We're moving into the lightning round now, because it's 10 to 5. We've still got another nine questions to go, I think. No, not quite as many as that. So, built-in RCDs. Sorry, Kurt, this is back to you again. RCDs and EV charging equipment. Obviously, the use of electric vehicles and charging points is very common now. It's almost standard installation work. What do people need to consider when selecting charging equipment and RCDs within them? Yeah. So, sticking with RCDs again. I'd say, first things first, initially to lay out, obviously, Section 722 brings additional requirements where we're looking at installation of EV charging equipment. Now, there is no specific requirement for an EV charging circuit to be provided with additional equipment. protection by an EV charging equipment. Depending on the EV charging equipment. Depending on the EV charging equipment. Depending on the EV charging equipment. It's a requirement around each charging outlet. So, that's, I guess, first things first. So, that initially opens the door to do in-built RCDs. Are they allowed? Well, potentially, because they're not necessarily a requirement from the origin of the supplier facility. That's general rules. You know, you might have an armoured cable, or going to the EV, or, you know, you might not require additional protection by an RCD for due to the circuit constraints. So, some things to assess when selecting these RCDs for each charging outlet. So, 722, it's a requirement that RCDs disconnect all live conductors. So, we've got an image to the right-hand side of the screen here. So, the typical thing, or typical image you will find for a single phase RCD. So, what we've got here is a single pole and switched neutral device. So, the protection is provided in the line conductor in terms of overcurrent protection. And then the neutral conductor will also switch, whether it be in a fault condition or isolation. So, it's a single pole and switch neutral device. So, that's maybe the typical thing you're looking for when selecting an RCD, let's say, to achieve the switching of all live conductors requirement. RCDs are also required to be of a suitable type. Now, Chris has just gone into a lot of detail in that. So, I'm not going to go too much into that. But 722, again, it lays out that you must select certain types of RCD. We're looking at a minimum A in conjunction with an RCD, DD. But there could be circumstances where we either need a type B and you're going to have to consult your EV manufacturer's information for that. Now, the key point to focus on here for us, though, is that RCDs are required to meet certain standards. And again, this is laid out within Section 722. It specifically states that the RCDs shall either meet BSEN 61008, 61009, 62423, or 60947-2. So, depending on the type of device, we'll depend upon what standard it would need to meet. But ultimately, you are required to meet one of those standards. So, going back to the RCDs. So, going back to the question now, can the RCD be inbuilt to the EV equipment? Well, yes, it can be built into the EV equipment, providing that the RCD meets one of the standards that are just listed. However, what we found with quite a lot of the inbuilt devices, when sort of pushing and probing with the manufacturers, they have maybe made statements to say that they're PCB compliant to BCB compliant to BCN 61008, sort of indicating that they meet some elements, but maybe not all. So, for us, something either meets a standard or it doesn't meet a standard. So, our guidance around this is, if there's doubts around the inbuilt device, then you need to fit an RCD somewhere upstream of a certain type. And I think a lot of manufacturers of EV charging equipment have sort of switched to that guidance as well. So, yeah, it's circumstantial, but exercise portion. Lovely. Thanks, Curtis. Chris, there's been some chat in the chat from, oh, where's he going now? John Johnston about bonding in flats. And you mentioned something about a rag question, didn't you? Yes, I haven't seen the, I've just skimmed the question, but I wonder whether there's a rag question or question and answer that may be applicable and I can post it in the chat if that helps. And hopefully that'll answer the question. But if not, please come back to us. Yep. Brilliant. Lovely. Thanks, Chris. Right. Moving on. Next one. Well, you took that answer, Chris. So, this is Curtis's turn again by the look of it. 717 and metal containers. What's a metal container, Curtis, and what's needed here? Yeah, just quickly, there's a question in the chat. I've just noticed. Is this connection of all live conductors a regulation? If so, do you know which one? I presume that's in relation to the EV stuff that I was just on about. And that's the regulation 722.531.3.1, presuming that that's in relation to that. So, yeah. Sorry. Yeah. Section 7, sorry. Does Section 717 apply to metal containers? So, we're looking at here the special location that covers mobile or transportable units. Now, two circumstances, two different answers for this one. So, if the unit is designed to be moving frequently and is hardwired, then it falls outside the scope of Section 717 and therefore becomes part of the general electrical installation and the general parts of 1 to 5 of BF 767. So, if the unit is designed to be moved frequently and is hardwired, then it falls outside the unit. So, if the unit is designed to be moved frequently, it then becomes within scope of Section 717 as it's then intended that ordinary persons will be unplugging the units and moving them about. So, to put some practical examples in for this. So, look at a bullet point 1 where something's generally designed to be moved in frequently and it has a hardware connection. So, if we take maybe some site cabins, site offices, often they are dropped off and intended to be left there for 6 months, 12 months, 18 months duration of the job with no intention of them being shifted about. So, typically, they would fall outside of the scope, subject to, of course, you know, whether they're going to be moved about and the connection time. Whereas, whereas we can see we've got an image on screen here. You can see a welfare unit that's on wheels. This is obviously a mobile or transportable unit because it's going to be moved about regularly. So, for that one, it's hopefully two simple examples and it's just determining the difference between the two. Lovely. Thank you, Curtis. Right. Next one. Oh, we're going into EICRs here and looking at general comments. Chris, EICR, lack of RCD. You've got a screenshot here. Where's this taken from? This is from the Best Practice Guide 4 produced by Electrical Safety First. Now, that's a fairly nice intro there, actually. Thank you for that. Look, we get a lot of questions on EICRs on the helpline. I'm sure we're not alone in this. And there's lots of debate, lots of discussion every day. Essentially, our input is always the same. Firstly, refer to industry recognized guidance. It's really, really important we do that. There's a lot of situations that we see where people have just plucked codes out of the air and they've just put them on a piece of paper without reference to anything. It's really important that we understand what the situation is and we, wherever possible, reference, recognize industry guidance. Now, this is a classic example. This is Best Practice Guide 4, Biological Safety First. The only reason that I mention that is because if you look on the front cover, there's lots of organizations' names on there to say, sorry, excuse me, that they have been part of the decision-making process. Okay, so that you can really take as the voice of industry. There are other documents too, which I'm not taking anything away from. They could be single source. But I would always come back to the recognized voice of industry if you can. Now, that document won't have every scenario known to man. And this is where we need to adopt something called engineering judgment. What is engineering judgment? It's this often used term, isn't it? So what is that? Okay, there's a huge drive in industry at the moment, predominantly coming from places like the Building Safety Act with regard to competence. The EAS is following up very shortly with regard to qualifications, training that expect QSs to have, et cetera, et cetera. And it all boils down to this. In order to perform any electrical work, we need to begin to be competent. What does competent mean? Well, it's a combination. It's a melting pot, isn't it? These items on the screen here. It's skills, knowledge, experience, and behavior. Behavior is a really important thing because I'm sure there has been more than one electrical contractor who's ended up in A&E who's got loads of experience, who's got loads of knowledge and who's got loads of skills. But on the day, they've just thought, don't worry about that. Doesn't matter to me. I've done it a million times. Let's short circuit something and problems happen. I'm not trying to belittle this at all. It's really, really important that we're aware of the dangers. But competency more and more is coming into our industry and it's got to be a good thing. We've got to embrace whether we like it or not. And it's a combination of a multitude of things. And where I'm getting to with regard to EICRs, it's very valued here. You need to be able to display these items when you're working on a system. For instance, if you have an electrician who might be very good in a commercial environment and they're fantastic in putting up containment or whatever it may be, and they've been doing it for years, they're competent, they're fantastic in the area. You take them out of that area, you put them into a domestic environment and say, right, full your boots, go and do an EICR. And they're looking at 30 million bar CDs. They're looking at weenie small cables. They don't understand it. And suddenly they're a fish out of water. And that's what I mean. It's about competence. So that is the basic level. You need to be competent. Then you use your engineering judgment based on your knowledge, your experience and your skills. But you gauge the weight of what you think something might be. If there isn't an example in the best practice guide, for instance. So you compare. If you're thinking C2, for instance, you compare it with the examples in the industry guidance. And you think, is it about the same? That's engineering judgment. It's not just plucking something out of the air and applying a code to it because you think it's that. It's having that deeper understanding and being able to verify it. You know, on the screen earlier, there was things about C3 for no RCD protection on a socket outlet. And the little line underneath about, you know, just because an installation was designed to an earlier version of the regs book doesn't necessarily make it dangerous. And that's important. That's knowledge. That's experience. That's an understanding of the situation. And being able to apply codes with that judgment. But anyway, I'm very well aware that it's 503. So I don't need to labor the point. But it's really important. Engineering judgment is that. And we need to use it properly. That's absolutely right, Chris. And I think, you know, guides and help and aid like that can sometimes be misused. People can take it and say, I have to do what this guide says. When it's only a guide, it's really up to the engineer at the time. Sticking with yourself, Chris, some things that you don't necessarily want to look at on an EICR or wouldn't code. What sort of things would you avoid coding, but maybe comment and feedback to the client on? Yeah, that's a really good point. I just want to cover off that last comment you made, though, Gary, just before we crossed over into this slide. And that's a really, really good point. There's nothing wrong with deviating from recognized guidance, as long as you've got the engineering judgment to back it up. And you can give that information should somebody ever question your judgment. You can say, well, actually, I appreciate that this is normally a C3, but on this occasion, it's a C2 because of XYZ. And you can justify the elevation with that judgment, with that factual input. Anyway, this is another common one. Get this all the time. What do I code? No smoke alarms or smoke alarms out of date or fire alarm in the wrong place or not the wrong type of system or something. And by and large, this has been driven by landlords, I guess. The information for landlords is valid and it may well be useful. And that's absolutely fine. If the electrician or the contractor is going to inspect the premises, it makes sense that they collect this data. But don't forget that an EICR, the intent of an EICR is to compare the electrical installation against the current regs valid at the time of the inspection. The brown book currently has nothing to do with emergency lighting, has nothing to do with smoke alarms, etc., etc. So none of that is codable. Certainly put it down on the sheet if you wish to for information for the landlord. That's absolutely fine. What is codable, though, if you've got an emergency lighting circuit, for instance, and there's a fault with the electrical wiring, the supply to the light or the light's broken, which means there's a C1 element to it, that type of thing. Now, that is very much codable. But the fact that it's a wrong escape sign or the smoke alarm is out of date is not codable. It has nothing to do with the brown book. And we get that all the time. But certainly maybe valid information that a landlord may wish to collect. Oh, sorry, Chris, I couldn't find the unmute button there. Yeah, absolutely valid point. I tend to look at this as being you walk into a building to do an EICR and you see the sinks leaking and it's, gushing water all over the floor. It's not electrical. You don't code it. But you'll probably want to tell the client that there's some potential harm coming into their installation. Okay, moving on now. We've got just a little slide here, noting some of the technical resources that we've linked out to, haven't we? And I think, Chris, you mentioned a couple of times the Electrical Safety First and their best practice guides. I think we've put a couple of links into the chat. There as well. Specific RCD. Oh, look at that. SPD will provide its functionality. No visual inspections or that's needed. Just an example of some of the good industry guides that's out there. And the nice thing with these things is they're free. You can download them, access them anytime you want, which is always useful. You also highlighted best practice guide four, which is probably the most used one. in terms of highlighting EICR codes. But as you say, Chris, what's really important here is not to absolutely stick to it diligently. You might find a situation as you walk into a building where it's absolutely totally different from what the guide was intended to aim at. So you have to use your own engineering judgment on that. Okay. I think we're nearly there now. So summing it up for the ladies and gentlemen at home. Wherever they are. Wherever they are. From North Wales to Uganda, by the sound of it. We've highlighted some of the common topics that we get asked every day on the helpline. This isn't all of them. And it absolutely can't cover all of them in an hour and 10 minutes or so that we've been here. But this presentation is aimed just to give you a highlight of some of the things that we talk about and some of the common questions we get. The guys have mentioned engineering judgment a couple of times. And ultimately, that's where we try and push people towards. We don't want robots going out there auditing sites, assessing things. We want people to use their engineering judgments. We want people to use the free guidance and the professional resources that are available to everybody on places like ESF or to ECA members on our website. And we've got loads. We've got lots of information out there. So if you are members, have a look on ECA.co.uk and we can give you some info on that. A couple of things in the chat there. Ian's talked about continuously supervised. I think I see what you said. There's a difference between something that's continuous and something that's constantly supervised. So if you're trying to improve something, you're looking for continuous improvement, which is sort of let's do a little bit and then go up and do a little bit and go up. You don't need somebody sat there. 24-7. We know toilet breaks. That sounds a wee bit unfair. Pete's comment about smoke alarms. Yeah, absolutely valid. Always have a little look and check on these. Just don't put it down as a code. Whoever said having a pint, I'd get very much in trouble with the better half if I did that on a Tuesday, I suspect. And a few other comments coming in. So if we've got a chance to take any other questions, we can do. If not, then we'll hand back over to Curtis Pierce. And hopefully that was useful for you guys. And you can all go off and enjoy your dinner. Perfect, guys. Thank you so much. I can agree with the chat there. It's a really informative session. I believe you guys have answered most of the questions that were coming into the chat. So unless there's any kind of last questions from the chat, guys, feel free. Lots of thank yous. Thank you guys for your time today. And hopefully see you for a future session. Thank you guys so much. Thank you, Gary. Thank you, Chris. And thank you, Curtis, for your time today as well. Really, really good deep dive today to those technical questions. And hopefully have you guys back on soon to answer a few more. Yeah, no problem. Thanks for having us. Thanks for listening. Have a great day. Cheers, everyone. Speak service. Bye bye. Cheers.