jpadie

Thank you.

Hello I am adding a new circuit from the main consumer unit to a garden room. The garden room will have its own consumer unit with surge protection. Current plan is that all the circuits in the garden room will be behind rcbos. The connecting cable will be swa and routed mainly underground save for a small part by the main distribution board (clipped and then through a masonry wall) and another by the garden room (behind the external cladding then through thick PIR). I'm concerned that the swa is not protected by RCD type device so was wondering whether it was permitted to put the circuit behind an RCD/RCBO on the main distribution board. I realise that any earth fault in the garden room will trip probably at least two protective devices.

Thanks all. I'm having to run bigger SWA after the walls have been closed. And I can't reuse the original cable routing as the service void is 20mm. The consumer unit is in a small cupboard and I need the whole width to be able to access and install a water tank. Putting a 22mm cable there will impede access to the point of making it impossible So the only route left I think is to go up the outside of the building behind the consumer unit (behind the cladding) and penetrate the wall (tyvek, osb, 150mm PIR and plasterboard) at a steep angle and enter the interior at about 5ft then gland into the bottom of the consumer unit. That will be high enough to allow access. Does the cable need to be derated materially for the short run in PIR? The remainder will be buried.

On the destination end. Sorry for not being clear on that. All the circuits at the destination are rcbo protected. The source end has no RCD protection.

Hello Is it normal/acceptable practice to remove the outer insulation and armour and gland off SWA into a small junction box once it gets inside the premises and run the rest of the distance to the consumer unit with just the internal common insulation? No joins but then the bend radius would be a lot more manageable for the routing that will be needed. The armour would be earth bonded at the main consumer board gland (ie the other end to the one I'm worried about. This is 3 core SWA so the third/grey core will be used as earth to the sub-consumer board) Thank you Justin

thank you. i don't have drain rods or a compressor (in the UK) sadly! or a long enough rope! and there's a belly in the duct that holds water. getting a rope through is going to be tough but I see the point. I do have a 20m fish tape. that might be good enough to pull back a rope.

Hi I am struggling to thread about 20m of 63mm MDPE down a 110mm pipe that's being repurposed as a duct. Are there any tips that might make things a little easier? there's a mild S bend in the middle and I think I may be getting stuck there. there's no easy way to get hot water into the pipe unfortunately. at the moment the leading edge is stopped up. I was thinking about removing the stop and cutting an angle there. it will be connected to a pump so any silt should get blasted out. thanks in advance. justin

i'm sure you are correct. Unfortunately I don't have the luxury of time to search out the right person. I've been using local community boards + fully explaining the circumstances. I don't want more delays so have paid the BC fee. the latest electrician has said (yesterday) that he will help with terminating the SWA which at least means I won't have to buy or rent an absurdly long hole saw to get through the masonry (it's a 16th century cottage so mostly timber, lathe and lime but the section to get through is solid lumps of stone, mudded together with lime. I suspect that is why previous electricians across the century have gone through the window frame.

No idea. He won't answer calls or texts. Hasn't since a couple of weeks before Xmas. No price agreed but this guy has done the electrics at this house for a decade now.

I was clear from the outset that this was a sign-off job. He asked for the second fix as well to make it worth his while.

Thank you. Your experience is extremely useful to understand. I'm a little concerned that I will get nowhere with this but let's see! I'm keen to get a second view on what I've done and will do from a safety perspective. The garden room is on the boundary and under a spruce tree. So if there's arcing or other fire starting behaviour from the electrics then there's a strong chance of very rapid spreading. I had an electrical fire from an immersion water heater (electrician installed) about 6 years ago. So it's an evidence based fear! That was caused by insufficient torque on the contactor leading to sparking. I don't buy the latest sparks saying it's too much testing though. There are eight cables, the ring main being the longest at about 15m. It would take 30 mins to test the resistance across all circuits before second fix. And perhaps 30 mins longer to run an NCD along the plasterboard to confirm that the routing is as I have said. I'd happily pay for an hour extra of time. The other testing a sparks would need to do anyway after a second fix. There are eight sockets, 7 down lighters, three switches, two immersions, a vmc and a tiny towel rail to connect. 22 "appliances". Even at 15 mins an appliance that's less than a man-day's work. Maybe the job is too small for an electrician to be interested in? Although connecting up the new 16mm2 swa is probably a half day in itself to be fair. Hey ho...

off I went. and the car broke down so I'm back at home with a motor in limp-mode! tried calling BC and had a conversation that I mostly heard. the lady didn't really know what was needed but said the fee for electrics was £400. she didn't want to take money until she'd double checked with her colleagues as there is no current BC application in place (internal floor space is 11m2). the fee covers up to two inspections and 8 circuits.

thank you all. I'm a bit deaf so cannot reliably call the BC to talk it through so I'm off to Godalming to knock on their door and get the right forms and fees.

Yes. Entirely happy to do the work myself. But I'm completely in the dark as to what needs to be done with and for building control. Hence my plea as to whether anyone can shed light on how this works, what is needed, to whom I talk etc etc.

dear all I've just been let down by a second electrician on a small project. the first approved the first fix for me to close the walls this was in med Dec. the walls are now closed and I took a video thankfully. the second electrician was quoting for second fix and sign off (small garden room) and pointed out that I needed a much bigger feed to the building. this evening he came back saying that he didn't feel honourable quoting as he could see I knew what I was doing and that it would cost less than 500 quid to get signed off by building control. whereas he would need to "spend many hours testing" what I'd done. I don't buy this personally as there are only 8 circuits and the wires are single runs. but reading between the lines he doesn't think he can be properly competitive and probably he is worried about complying with his NAPIT scheme. So ... can anyone shed some detailed light on what the process is to get signed off for the electrics, please? I've been out of the UK for 25 years and have no idea about this stuff. thanks in advance justin

thank you.

Hello all i need to install a sump and pump to remedy a waste line that's got a couple of bellies. the fall was always only "just" ok so it's time to bite the bullet. it's only to serve a couple of very occasionally used shower rooms so I plan for a relatively modes sump basin. the sump basin will be buried under some placed (rather than concreted ) crazy paving. my question is about the base for the sump. i've got some hardcore in there at the moment. In France, where I installed a sump a few years ago, the advice was just hardcore under the sump, place the sump and level it, fill the sides with hard core to about 12" from the top and finish the rest with concrete (putting some heavy things in the sump to prevent ground water from moving/lifting it before the concrete had set up. Is this the norm in the UK - I've seen references to concreting a 10cm slab for the base over here. thanks justin

Thank you. that's an idea. expanding foam and silicon to seal and water/bug proof the holes?

Changed the prv to a new reliance 22mm version and that has certainly helped stop with flow and stopping the persistent dripping from the hot water circuit. Flow rate from the kitchen taps is low at 4.5l/minute. Cartridges are clean. I think the only solution to this is to change the tap for a higher flow rate alternative but I am open to suggestions before investing in new hardware

the electrician is doing the sign off. i am doing everything else. He has expressed a preference for _not_ taking the SWA up the wall and into the house. ok - how does one get the SWA to bend sufficiently to come up the wall and go through a window frame, bend right and then down to the consumer unit? (this is the entry route). it looks like the bend radius is min 130mm which makes this kind of routing seem challenging.

That's not the whole situation. this is for a garden room that the electrician has said needs at least 10mm^2 cable. the connection will be from the main consumer unit to a local consumer unit in the garden room. the majority of the wiring from the local consumer unit will be on 2.5mm^2 t+e, all on RCBOs. The extra capacity is to allow for a car charger in the future. apologies - this post may shed light. what I was originally looking for was an idea of what type of connection to use and whether there were existing commercial solutions (e.g. wagos for 2.5mm^2 cable in a plastic junction box) for high current connections on large cores. But I see that my question has opened the door to rather more issues which are all valuable knowledge! the main length of the SWA will be buried in conduit (there is existing sewage pipe that is being decommissioned that will make it unnecessary to dig a trench. the tail at the end of the main consumer board will be brought up by the side of the house and clipped until termination. flat cable = t+e yes. apologies for not being precise. I did not know that. the house already has a reasonable number of t+e cables clipped to the outside of the building; i made an assumption that this was ordinarily legitimate. the bend radius for the swa (to me) makes it look impractical to clip to the wall and take inside. I might be misunderstanding though. the electrician recommended terminating on the outside of the building. possibly he meant that the armoured section could be terminated and then just run the inside of the cable up the building and into the house? is that feasible?

What's the best way of transitioning from 16mm^2 SWA to flat cable please ? Am planning this to be just above ground level on the exterior wall.

Hi all I've been having poor flow rates in the kitchen and bathroom for as long as I can remember. about 3 years ago I changed out the PRV and twisted the adjuster until my other half said the sink was filling quickly enough. Job done I thought. Lots of dripping from the pressure relief valve going to the hot water cylinder (whether the water was warm or not) and sometimes a lot of flow from the PT valve on the cylinder got me thinking about water pressure generally. the manometer on the PRV and a test manometer I fitted to a tap bib show inside pressure at 7bars. this stays the same whatever I do to the PRV although the flow rate seems to change a bit when the PRV is adjusted. I've cleaned out the PRV completely (but it is not a replaceable cartridge type, just having a metal grille. I cleaned it by giving it a citric acid bath for a few hours, then some mechanical flushing). pipework is wide bore MDPE coming into the house (42mm I think) going to 22mm copper into a low loss manifold from which there is 15mm PEX lines going to the kitchen and the master bathroom (separate lines). I _think_) the mixer taps may be very narrow bore (I will check) but I was wondering whether there was any advice from the community about 1. what other things to look for in investigating low flow rates; and 2. what causes a PRV not to adjust the pressure? FYI there are three outdoor water outlets that are on the supply side of the PRV and they are all good flow (e.g. I use 25mm mdpe to a 100m3 pool and it fills up within the inside of a summer's day (16-17 hours)). thanks in advance Justin

great response! many thanks. there's no obvious wind/leeward side as the surrounding foliage stop any extreme wind. if anything the roof joists run perpendicular to the prevailing wind so if I'm lucky I might get some low pressure areas under the soffits.

thanks - I've seen so many different approaches (so called hybrid?) that I thought it best to seek the wisdom of the masses! thanks - soffit vents it is.