When BS7671 Meets Reality

Added: 2026-05-25

[00:00:00]Hello again. Today I'm going to be taking you through the installation of these sockets and some lights in this greenhouse while banging my head constantly on this bench above. Let's get straight into it. So, this is my workspace for the next few days. I have this greenhouse to wire up. I've got these lights which are a bit of an issue and I'm going to have to actually deviate from the rigs to wire them because the manufacturer doesn't allow fixing to this frame. It voids the warranty. So, we're going to have to come up with a way of getting the cable up and it being safe. I mean, the issue would be protection against premature collapse, but as it's a greenhouse, I don't know. I don't think firefighters are going to be coming in there in a rush, so I'm not too worried about it.

[00:00:42]Let me explain the job. So, two lights up above. They're already in place.

[00:00:47]Then, we have a switch going over here.

[00:00:50]So, I know it's quite low, but this is the only bit of wall that's actually I can't exactly put it on the frame. So, there's going to be a switch down low level, and it's going to come around.

[00:00:59]We're going to have three sockets along this part here. And then finally over to that corner there. Another socket somewhere around there. Going to consume your unit in the corner. Got my duct there ready to pull my sub main over.

[00:01:13]So, I've got a six mill SWA coming over to here. So, it's going to feed a IP rated fuse box. Um cuz we're in a greenhouse, it's quite wet. Elder sockets in here and accessories are going to be weatherproof. Uh so they got a bit of a splash cuz I mean as you can see water does all plants and stuff. I'm not a very green finger. I'm from London so I don't know much about plants but that is the plan. So IP rated box there.

[00:01:38]Um I'm going to put a cuz of the temperature changes in here. In a greenhouse it gets very hot, very cold.

[00:01:43]I'm worried about condensation. So, I'll be putting a vent plug inside the fuse board so it can breathe a bit. So, we don't get any buildup of condensation and rotting terminals cuz as I've mentioned before, DBs shouldn't be going outside in an enclosure cuz you can get the condensation build up and it starts rotting from the inside out. It's the same thing in here. The sudden temperature changes, it's going to suffer from. So, hopefully I can prevent that with a vent plug. Anyway, all black condrate today. I'm going to be going around just saddles and whatever else.

[00:02:12]So, I'll take you along for the ride.

[00:02:14]Uh, there's not much space in here, so I'm not sure what I'm going to do filming wise, but let's get into it. So, I've just been marking everything up.

[00:02:21]So, the edge of my switches go in there.

[00:02:23]So, the gap between there dictated where that saddle went. It's about aesthetics.

[00:02:27]Obviously, I don't want to exceed the maximum gap. But, so that's then set the space for that saddle so that they're symmetrical, which then is the same space again, which starts my double socket, which is just here. That's then going into my T which is here. And then what I've had to do is dictate this socket down here in the corner is there.

[00:02:51]Now that means that this socket here I want it to be symmetrical. So it's the same distance between them. So that kind of set the standard for my other saddles. So I've got that as my dat point on the edge. Then I'm got my safe saddle space. So we've got one, two, three into the socket. Now that gap isn't uniform. So that was 36 cm. So what I've done is mirrored it on this side and come 36 cm to that that fixing and then jumped across and then going back to our standard 40 cm gap which goes along and it worked out nice because when you imagine it complete when saddles can look really really ugly sometimes. Um, you want to be an equal distance from accessories. So, if you try and plan it out, now I'm not planning to be a conduit master here.

[00:03:44]It's just that it's all about aesthetics. So, sometimes if there's a saddle and then immediately a conduit box or a saddle and immediately after a socket, it kind of looks a bit silly.

[00:03:54]Whereas, if you can get even spacings around it, it just aesthetically it just symmetry is nice, isn't it? Um, and that's what I'm trying to do. is just trying to plan out a little bit of forward planning now rather than working from a fixed point and then realizing oh damn that saddle needs to go there and it's right next to a box that kind of thing. Um it can also change your saddle spacing. So if you just come in the same so you got say a socket here socket here if you come in say 20 cm 20 cm then just go dead center as long as it doesn't exceed it and it just looks nicer. If you can get them all uniform it just it's more aesthetically pleasing. I mean granted no one's ever going to see it.

[00:04:32]It's going to be plants and stuff stacked underneath here, but I know it's there and I want to try and do a good job. Um, with this cuz it's quite tight in here. I'm actually I know what a cheat. I've actually got some inspection elbows so it's really tight in the corner. So, it just means that the conduit is really really tight. I ain't got it cuz I can't bend conduit before I get slated in the comments. I just think it's going to look better with these really tight in the corner. If I keep them that way up as well when you look down on it, it's just going to look really neat.

[00:05:07]That's the plan anyway. So, I'm marked up till that corner. Just need to go beyond that from my T round elbow across and then there's a socket to go there.

[00:05:16]But I'm going to do the same thing planning out the whole job. All of my saddles are going to be marked. Then I can drill all of them, mark all of them, and then I put my accessories to suit the conduit between. Um, it's the way I do steel conduit as well. I always do all the saddles first and then make it to fit my saddles because the fixed points of where they got to go, the sockets have to go to set height. The in the inspection through boxes or wherever have to go in certain places cuz obviously you don't want to have too long a run. I think a rule of thumb is two lengths of conduit or 180° of bend before you need an inspection tee cuz uh or through box cuz when drawing cables it can be an absolute nightmare. But that's the plan. That's my thought process. Let me know in the comments if you do something different. And uh I want to carry on. So as you may have noticed, I'm not the most felt gentleman.

[00:06:09]Some would describe me as husky.

[00:06:13]what I do anyway. And this is definitely giving Nutty Party vibes cuz I don't know if you know about that cave, but I have nightmares about getting stuck in that claustrophobic position. But these shelves look like they're a pain in the butt to get out. So, I'm just going to suffer. I've only got to get a saddle here and here and then one on that back wall and then I should be able to crawl through from where the camera is. But yeah, it sounds like these I wish I had an apprentice or made better choice better life choices with my diet.

[00:06:49]Anyway, let's get measuring.

[00:06:53]Let me take you through deviation from the regs that I've got to do at this property. So, this is sticky back finger trunking. I don't know well you can see that. So, it's decorative trunking so that you can uh hide if you're going around trim and different bits. But basically, the manufacturer of this greenhouse has said that you cannot drill or tap or anything on here, nor is there any holes in it cuz my original plan was to drill, tap, put cable bases along, and neatly clip the cable, but I'm not allowed to. So, the customer doesn't want the uh warranty void. So, what the manufacturer recommends is this. So I've installed have to install this just sticky back up and over. Now cable should be secured against premature collapse in event of a fire that kind of thing. Look where we are.

[00:07:45]We're in a greenhouse. There are no combustible materials in here.

[00:07:50]There's nothing really to catch fire. I mean I suppose the heater, but this is just a temporary thing. There's going to be like a couple of heaters in here and that's the worst that's going to happen.

[00:07:58]And this isn't a place where firefighters are going to fight a fire or anything like that. So, it is a departure from the regulations and it will be noted on my certificate that this cable has not been fixed. So, let me flip you around quickly.

[00:08:11]So, we got to go. It's actually I mean this stands out like a sore thumb, but can you see it yet?

[00:08:19]So, I've just stuck that up there and then there's a piece just coming up here and it finishes just at the top there.

[00:08:26]It's annoying that this piece of cable isn't long enough for it to reach and go all the way down.

[00:08:33]It's just too short and it's pre-wired, which is a bit of a bugger. So, got to try and make this cable look neat and have the joint in this side. And then it's going to come out the top of the finger trunking and then just nip down into the joint and then kind of zip tie it around here and then onto the light fitting itself.

[00:08:54]So it looks neat and out of the way.

[00:08:56]It's going to be the same for this one here. It's just that you're not going to see it because it's going to be on the back edge of that one. So yeah, that is the departure. That is the trunking that I'm dealing with. Look at those techers.

[00:09:07]Um, so I've mited that bit and cut that.

[00:09:10]I'm going to mirror it. I've got these two pieces here to stick up there. And I'm just going to carry on with this trunking. Annoyingly, I ordered the wrong size flex. So the flex I ordered is 1 mil and it doesn't fit inside that finger trunking. So that's a bit of a bugger. So I've ordered some some screw fix. I'm here for a few days. Um so yeah, that's the departure. Shoot me down. It's never going to be a danger or hazard to anyone. So yeah, I've agreed to do it cuz no real way of doing it in all honesty. There's no holes and he doesn't want to void his warranty cuz imagine if you drill this steel and then moisture gets into it, it's going to rot and then the frame's going to Yeah, you get the idea. Anyway, anyway, I'm going to carry on. Okay, I'm in amongst it now below this bench, banging my head constantly, but I'm working from a fixed point. So, the switch behind me here and then working my way around. So, it's easier to work from a fixed point cuz then you can make micro adjustments. Say this, I've marked the socket to go here, but might be a case that if it goes 2 mil to the right, it's going to be better for me in terms of fixings and whatever else. So those micro adjustments can be it's it's more poignant with a steel conduit cuz if you're a millimeter out it's thread in and doing whatever. This I can just quickly cut a sliver off. But working from a fixed point hopefully you can see in the corner. So it's like equal spacing. So it's equal space equal space equal space and then equal space to the socket so it doesn't take your eye away. There's nothing worse than when the saddles are spaced awkwardly.

[00:10:40]Um, so yeah, I'm going to carry on working towards you back toward the fuse board and getting this all fixed together. So, I'm going have to call it there because I'm losing the light. It doesn't look like it to be fair on the camera, but I am losing the light. Um, I've got it all first fixed. Got all the conduit up, all the bases up going all the way around round to the fuse board over there, which was a nightmare because where the conduit ended up coming in cuz there's a waist pipe in the way. I've had to avoid the waist pipe by putting the board up more because otherwise the flap wouldn't open. But then that meant the conduit wanted to land exactly where the drail was. So I've had to just put like a little kick.

[00:11:17]Didn't work. Um I tried warming it up a bit. Hang on. One, two, three.

[00:11:23]I tried warming it up on the heater. I tried warming it up with a heat gun to try and get it just more malleable to give it this work.

[00:11:33]So, I've got it into the board now because the water has to come up on the right. Even though my cables on the right, I was expecting the board to come right over to the front edge here, but it's in the corner now. So, that's where the customer wanted it. So, all first fix, which is good. So, now it's just second fixing. Well, I say all first fix, the containment's up. I've got to pull the cables in to be classed as first fix. So, that's the plan tomorrow.

[00:11:59]So, I'll join you then. It's day two.

[00:12:02]you join me up a ladder. So these joints here, they're like little torpedo joints.

[00:12:09]You got a little connection there and then like a stuffing gland either side of it. So I'm jointing this through.

[00:12:15]This is what actually came with the fitting itself. And I'm sort of taking up this frame here. So don't block this decorative A. And then it's going to go sit in this sort of area here hopefully if you can see that. And then the other bit of cable's going to come out of this bit of finger trunk in and onto it to connect up. It would be great if the uh flex on this was actually long enough to reach all the way down. I wouldn't have to joint in it. I mean, it is designed to be jointed somewhere. But it's trying to make it look decorative in here cuz it's just Yeah, it's nice to make things look nice. Anyway, I'm going to be jointing this light, this light, and getting the trunking done. And then I'm going to start wiring down below. I still need to get a submarine over today. Um, and as it's not raining, it might be the ideal time to pull in my six mill submain. So, check with you in a minute. So, now it's time to start wiring up. So, what I'm going to do is get a measurement of all of the cables that I need to pull in. So, from the fuse box here, measure around to the last socket and then allow a bit to second fix each socket. And then do the same for the lighting because the light has got to come round to that bezer box there and then round to that bezer box there. But then I need some strappers, a switch line and return to go a live to go all the way around to the switch and a switch line to come back. So there'll be one live that's sorry line conductor that's going to go all the way to the switch and be long enough for that. Then the the three line neutral and CPC for the socket circuit needs to be long enough to go around to the furthest socket.

[00:13:46]And then the live neutral, sorry, the neutral and the CPC just needs to be long enough to go to that bezer box and that bezer box down there. So, I'll get them all cut to length, get them all tied on and all staggered. So, I showed it in another video where I go through some two-way ray lighting. So, I'll leave a link to that in the uh description, but I'll go through how to join on singles. Probably might show briefly in this video, but if you stagger it, it makes it easier to pull around corners. I've got some draw tape that I'm going to push through all the way from the furthest point around round to the fuse board. Get them all tied on and pull it all the way round to the end. And uh fingers crossed it goes well cuz what you don't want is pulling cables past cables cuz you can end up burning cables. If you can pull them all in at the same time, it is better cuz you imagine the friction pulling past each other. It can end up burning a cable. You mean you do get cable lubricant yellow 77 which eases it, but it's best to just pull it all in one.

[00:14:41]Well, that's how I was taught to do it anyway. So, I'm going to get that drawer tape through. Get these all cut and then get it pulled in. So, I've got this all tied on and together. So, you can see it starts off with one. Then, I just I feed it through the center of one of the cables and wrap it around. So, the idea is if you can see it on camera, that's one. Then, so it gives it a chance to go around the corner, chance to go around the corner, chance to go around the corner. So, it's just getting slowly bigger and bigger and bigger. Giggity.

[00:15:10]And uh it just means when cuz there's tight elbows on this, it will struggle going around the corner. If they all come through at once, you imagine this big wad suddenly meeting in the corner.

[00:15:20]It's going to struggle to get around. So if you stagger it like this, it'll pull through nicely. Obviously pulling past other cables, put tape around this, but there's no need to if it's just pulling through new conduit.

[00:15:31]So I'm going to tie that onto my drawer tape. That's going to pull the line neutral CPC round for my socket circuit.

[00:15:38]And then it's the same for my lighting circuit. And then when I get to the bezel box around here, I'm going to tie on another switch line onto this bunch rather than pulling it all the way around from here. Tie one more on. And then I pull that all the way to the end.

[00:15:52]And then I can just pull loops out at each socket and at the bezel boxes. Give them a twist. And that is me completely first fixed. So it's just an easy way rather than cutting just have it all together and pull it in a one. So okay, that's that all wired. So, I've just pulled loops out at every point. So, this is the end of the line for this socket. And then it just means that I pulled it all through and just pulled out a loop at each point. So, if I briefly flip you around, you can just see that there's a loop pulled out at each point. And then at the conduit box down there, just makes wiring a little bit easier. You ain't got to cut and whatever. Everything's just in one piece. So, if you do need a little extra slack, you can pull it and so on and so forth. Teaching people how to suck eggs, but it's just an easier way of wiring.

[00:16:34]Um, the other thing to note with conduit systems is that you don't need the each cable at each point. So these only need the switch line here. So I've pulled the permanent live directly through and it's going straight round to the switch line.

[00:16:47]Then it returns from here and then goes to those points. So there's no point me having it just in a connector block there. There's no need for it. It's the same with neutrals. I don't need to drag the neutral round to the switch. There's no need for it. They stop at the pizza box here. So, it's just a simpler way of wiring. And it's just something to bear in mind cuz when you do sort of domestic wiring, it's always twin and earth and just a live neutral earth at each point.

[00:17:10]With conduit systems, it might not be.

[00:17:12]You might just have the neutrals at the accessories and then the permanent lives at the switches, especially on lighting circuits. Anyway, I'm going to get this second fixed. Um, you may notice that this is an actual BG outdoor socket. One thing they actually do well, um, they come with these little grommety things that you stick over the screws, put a bit of silicon in there, drill a drain hole, and then they do stay pretty watertight. So, cuz I'm underneath a flower bed that's get water that gets watered, so that it could run down and run onto the box. So, it's just better to be safe than sorry. Probably okay, but all weatherproof accessories going under here. Anyway, I'm going to carry on second fixing and I'll join you back at the fuse board. Okay, I've got my six mill here, which I need to pull through a duct. I've got my rope here ready to tie onto. Now, when we're tying our rope on, what we need to do is if you just wrap it around like this, it just it's just going to come off. What you need to do is put an opposite loop on it. So, as it goes on, if it's pulled, it tightens.

[00:18:10]So, you see that?

[00:18:12]So, if you keep putting the opposite loop on, pulling it tight, and feeding it down, and you put a load of them on.

[00:18:19]I'll put a load of them down it and then tape it up so when you pull it just keeps getting tighter and tighter so it pulls and doesn't pull off. That is the idea anyway. So, I'm going to get this tied on. I'm on my own as well. So, hopefully this pull goes well and the duct isn't got loads of gravel and whatnot in it. And uh yeah, then I can get this connected up into our board.

[00:18:40]Right, it's the next day. Basically, the ground workers started using a whacker plate outside. It made it impossible for me to actually show anything. So, let me flip you around. Got the cable through.

[00:18:48]In the end, there was actually a brokenoff cobra in the tube. So, I got the cable halfway down. It got stuck and I pulled it out and that came out with it. So, nice. But the armor's up in terminated. The DB is all terminated as well. Just need to torque it up and stuff. So, I got to go and make off the other end of the SWA.

[00:19:07]And then it's just like the little elbows and bits and bobs. Basically, just got off. It's all second fixed.

[00:19:12]Just got to go and do that end. put all the little bits of trim on the corners on the little elbows. Give it a nice wipe down and then that's in here completely done and then I can start testing. So I might as well go across there, terminate the SWA there and then I can sort of work methodically from there so I can zap this bit of cable do my R1 R2 then my Z here and so on and so forth. So yeah, let me take you through to switch room. So this is our main position. This is the board I'm going to be connecting into. So, we just got this little hager board here. Now, in the future, there's actually going to be a new freephase supply being put in in the far corner, and then I'm going to be installing a freephase cable over to here, and this is all going to be done up. So, there's going to be a freephase consume unit in this space here.

[00:20:01]Obviously, this old head will be gone.

[00:20:02]The meter will be out of the way. So, it's just going to be that will be inside the meter covered outside. So, it should be quite a good job. Big job I can take you along for the ride. So here is our S swa, but I'm only going to be sort of that's temporarily connected. So I'm going to be leaving a load of slack underneath the floor. Just bringing it out and pop it into the front. So it's going to look like a lash up, but I want to leave loads of length on it because I don't know where it's going to be terminated in this three-phase board cuz it's going to be like that and it can go to any one of the ways. I'd rather leave all the slack on it than dress it in neatly. Plus floors changing. You can see there's a manifold. It's just a bit of a a busy area.

[00:20:38]But that's the submain that I've pulled over. Goes through a duct into a pit outside. It's absolutely bucketing down.

[00:20:45]So, I'm not going to take you out there.

[00:20:47]Then through the inspection pit. It disappears off to the greenhouse. So, I'm going to be installing a 32 amp RC R MCB on here just temporarily. Um, and it's all got the correct typing and everything like that, but I'd like to shift this all along and stick it on its own MCB without disturbing this RCD cuz then I'm not going to have selectivity between the devices. But it's a temporary measure. Like I say, in a month or two, this is all going to be ripped out and upgraded. So, yeah, should be uh should be a nice simple termination to do cuz normally you got to try and measure it off the length and stuff like that. So, I can't really show you tips about that. I'm not going to show you how to strip armored because I'm sure you all know how to do that.

[00:21:31]So, let's get it in. So, now we got that terminated. We need to carry out insulation resistance test between all of the cores. So, go on line and neutral there. It's going clear. Let's lock that on. Move that over to the CPC.

[00:21:46]And we are clear. And then neutral CPC.

[00:21:53]And we are clear. Now, I would go to the gland, but this is terminated to the earth bar, the other end. So, the armoring is connected to earth. Had I not terminate the other end, then I'd want to go to the sheath of this cable as well, cuz that could go down to one of the inner cores. So, we're all good.

[00:22:08]So, I can connect up this into this board and then start testing the other end. Okay, I'm back in the greenhouse now. Done my loop test there. So, we're basically safe up to the top of the main switch. Now, I need to carry out all my dead testing in here. So R1 R2 insulation resistance and to prove polarity. Once they're all done, then I can start living it up to do some live testing here. So got a linking at the board. The link's resistance is 0.03. So I know that measured it before multiple times rather than me keep changing the zero on the tester itself because you imagine every time I'm doing that test, I've got to recalibrate it. So if I have the leads nulled, I can just take that 0.03 off of the reading that I obtain.

[00:22:48]So just going around sockets now.

[00:22:51]Hopefully you can see that reading there. So 0.07.

[00:22:56]Go to obviously this should be getting higher the nearer I get to you.

[00:23:02]Let's try this one out.

[00:23:10]That cup is in the way.

[00:23:13]So, we're getting 11, about 10, and then there's one behind you.

[00:23:24]Give me a sec.

[00:23:28]Smooth transition there.

[00:23:35]And as expected, this is our highest reading. So, 0.1 4. Land on that. Um, so I got to do a measured value on this and we can check if it calculates out. It never does to be honest. The reading I got at the dB here was 0.10.

[00:23:52]So in theory the ZS at this point should be 0.24. Oh wait, tell a lie. Got to take off.3, haven't I? So the reading here is 0.11.

[00:24:03]Add the ZS which is 0.10.

[00:24:07]We go 0.21.

[00:24:09]So we'll test that later and see if it works out. In my experience, it never does, but we can see. Anyway, I'm going to carry on get the I won't bore you with the details of all the other testing. It's just to show you this circuit particularly. I'm going to carry on my IR testing and um I'll join you when I'm livening this up.

[00:24:30]And just like that, we have light. Now, all I got to do is my live testing here.

[00:24:36]But as you can see, this is our measured value at this socket, 0.25. 25. Now remember we had 0.10 as our external and 0.11 as R1 R2. So it's not too far off.

[00:24:49]You got to remember we're measuring impedance and not resistance. There's quite a few bits that can change this value. Even if they're taken at different times of the day, the resistance externally can fluctuate. So don't get too bogged down on it. If they don't measure out in a perfect world, they would, but they seldom do. So, I'm going to get the rest of these sockets tested, lights tested, and um nearly there. So, that's everything all buttoned up and tested, all done and dusted. Just running old Heza around. It was a bit poorly and lost the wheel on its travels.

[00:25:25]Um so, yeah, all done and dusted. Wasn't too bad in the end. If you would like some electrical works doing, there should be some details down in the description below. Uh hopefully you got something out of that and I'll catch you at the next