Power And Lighting In Workshop - Shed.Part 1 

Vvv

Probably fed up with cooking

In reality. When you think about it....mass production... could be thousands out there.... doesn't anyone ever check this stuff?

Yes your correct I had to double check my laser hadn’t gone bad.🤣

I always do, but the chances of the box becoming live unless by a cowboy, are negligible in reality...

Correct, when I was at college in the late 80's, we were taught to always install a 1.5mm supplementary bonding conductor to the back box. Technically it is a "Class 1" box and must be earthed as such. But regs are open to interpretation ;-)

The way I like to think about it is would anyone be happy to earth a metal clad back box and rely on the mounting screws to provide the earth to a socket front? They are both exposed conductive parts at the end of the day. On the flip side of the coin, where the back box isn't accessible, as in a normal recessed socket where the socket front is earthed and there is a fixed lug I don't see the need for the flylead, but where a metal back box is accessible I always provide a proper earthed link.

It would be interesting on what competent person schemes have to say on this matter, both with metal clad and recessed back boxes.

Would the contact from the metal fascia along with the screws not give you enough confidence that the back box was sufficiently earthed in the event of a fault?

Yes I agree but client wanted white incase he decides to paint it

Right, no flexi crew christmas card for Chris then 😡

Alex Dougherty I’m going to Nicks for Christmas dinner this year.

@@Cjrelectrical 😂😂😂😂

@@Cjrelectrical cool.. All sparkies round to Nick Bundy's for a flexicon Christmas 😂 yo ho ho...

Upset after that slagging off at the start I dont see a single fabricated bend....... ah well

Can't picture what you mean Andrew.

Me neither

I have always hated rings....if a kitchen circuit needs 32amp we use 4mm now and decent outlets

I dont understand why you would sleeve cpc within the T&E, surely if a live conductor becomes exposed from its own sleeve then the first thing you want it to do it contact the cpc?

Ha, ha... I think we all do.👍🏻

Wait for part 2 👍

@@AndyK.1 big and ugly lol maybe you should get one made by yves saint laurent

@@AndyK.1 lol..

get an ad blocker. I didnt get any ads

The swa supply from the house is earthing the new board, the new rod he's going to be installing will be covering the circuits in the new board

@@djwazz07 Yes the supply cable will be earthed from the house end. But my question, was just asking for the reason not to export the earth from the house to the shed.. The house is already a TT system, adding an extra stake in the shed makes sense but you could just add one in parallel reducing the overall Ze of the install. Saves messing around glanding off into a plastic box.

The SWA's cpc is connected to house, then should be insulated from the earth spike which does everything in the shed if you choose not to export the house earth

Yeah i wondered that...

I believe he said it's because he's earthing the shed separate from the house because it's a long way from the house....but don't quote me on that, I'm not a sparks so.....

It’s not a junction box. It’s simply a plastic box to gland the armoured cable into as I don’t want the metal armoured to touch the new metal consumer unit.

Good call Chris 👍

I'm curious too. There's more cable used it seemed as well.

Or two 20a radials, then the conduit could all have been 20mm except for the drop from the board. If the cost of another rcbo is a problem maybe take the lighting off a fused spur. Lots of ways to do it though

Should have been a radial.

The main supply is already a TT and the out building is quite a distance from the house. The earth resistance at the out building if using the earth from the house would probably be quite high.

Check the onsite guide for spacing

I do not understand why new installations ever use a ring, the original purpose of a ring circuit was to save copper and cable but a ring can overload the cable if the ring is not complete. As you say surely radials would have made more sense here.

Maybe you could use hot glue?

John Ward has a good video explaining them, worth a search if you're still unsure

Price/cost

CJR ELECTRICAL With you on this, in the domestic world I can’t imagine clients willing to pay for Dado or 50x50 trunking that’s some serious cost compared to conduit! I’m just guessing here but I bet you’d lose the job to the next guy on price if that was quoted?

With Metal clad sockets? I don’t think so.

And why not?

Jamie Vaughan Well for one there are knockouts specifically for conduit entry. For two if you didn’t have conduit entry boxes making an entry to neatly align with the PVC trunking would be rough, Time consuming. I’ve only ever seen PVC trunking used with plastic patresses. Note. I’ve never seen a PVC trunking install with metal clad sockets. As a Sparkie it’s just not industry standard

That's why we use 20mm holesaw cutters and adaptors.

Jamie Vaughan Must be a new thing then. Never saw them in the 15 years as a sparkie in the UK

There is only 1 earth rod in the installation all will be revealed in part 2

Was gonna say the same more the better? Also do you take off House CU from incomer as distribution not as a MCB/RCBO?

@@stephencoulthard1718 Also a good point on the supply! Our workshop (in UK) is from the house from 1 of 2 CUs (1 house and 1also in the house for garage, outbuilding, workshop, external lights. From that CU a feed is taken from a 45A RCBO to the outbuilding CU which has RCBOs (sockets, lights, table saw, water heater). The house has an earth rod as does the outbuilding and the earth is continuous through the 6mm SWA (about 30m) to both rods all using 16mm earth cable. The house is TT. I guess thats the correct way of doing it but I have seen a split distribution but then you only have the fuse protecting the SWA.

My house CU on 10mm (original, might up grade as on 3/8 rod) then I Have 16mm> 5/8rod in Garage and on Hot Tub 5/8rod and now Electric Gate also needs 16mm2> 5/8rod. so that's 4 rods I am gonna have and all connected through. I picked larger rod because why not, when you need it ? I also like the SWA and the earth core contected.

@@ColinDH12345 Personally I wouldn't fault you, but my first job done alone and used for NICEIC assessment was a garage, taken out of mcb protected by rcd in the house, then rcbo'd in the garage. Assessor mentioned it would be better not to have RCDs/RCBOs in series as it would be a nuisance if a single event tripped both (being in different locations). These days my preferred method, where possible, is to run SWA direct from CU in house (or wiskabox right up against side of CU to make terminating the SWA easier) to CU in shed, mcb only in house and RCBOs in garage/shed/whatever. This only applies where going direct to garage/shed with no stops for accessories like external sockets on route of course. The advantage is if something does cause an RCD trip while in use nobody needs to go marching through the house in dirty boots to go flick the switch back up.

Cost and client wanted conduit.

I was wondering why he did not use singles..

He explains he uses T&E as it’s circa £50 for a drum (Plus will get used on other jobs), that’s £50 for Twin and CPC...singles are £30 a drum...£90 almost double the cost on cable and might not be able to be used on another job for a while etc...money tied up in materials etc. That’s my understanding anyway, I would have done it exactly the same as this, In fact I have for similar jobs I’ve done.

@@JayTheSparky Exactly, I got some 1.5 single on my van for 3 years i bought for a job, used a few metres of it for a shed job, now gathering dust...just use T&E in domestic jobs. lol...

@@JayTheSparky Yes but time saved on running the cable thru the conduit would cover the cost. And extra room for more expansion.