conservatory electrics

[wesj]

I am fitting a bathroom for a customer who has had a conservatory built across the complete rear width of his house using different trades to carry out various aspects of the works.His builders ran 2.5 T&E in the cavity to 2 twin metal back boxes on each extremity wall the one butting up to the lounge and the other to the kitchen and left a small coil of cable by kitcen and lounge walls.He called in a sparks who said he did not want to take the job on saying it was bad enough running 2 spurs from one intended socket supply in lounge and kitchen but he could not certify taking a supply from 2 separate rings, kitchen and lounge to sockets in one area ie conservatory. What he did say befor realising that supplies were intended from 2 circuits was that the 2 spur situation could be overcome to meet regs by connecting 13 amp FCUs between supply sockets and 1st spur but this would limit the total cumulative load on each pair of spurs to 13amps.I told my customer I would post on this site as he is now pulling his hair out,plastering,plumbing floor tiling all completed,builders paid and long gone. Any ideas/suggestions/comments will be much appreciated.Thanks in anticiption Wes

 

[THRIPSTER]

Sew,

Ih he doesn't anticipate using any more than 13A then use FCU's.


Regards

 

[wesj]

Thanks Thripster,but how about coming off 2 circuits with regards to certification? regards Wes

 

[Lectrician]

Thats no porbs either, but cables in the cavity is not good - especially is installed by builders who have no respect for cable at all.

I hate builders who think it is their job to run cables. We don't build their walls do we.

 

[fattony]

how would you run cables in a conservatory which is going to left be brick faced, I've never wired a conservatory, I fully understandthe cables in cavity is not allowed but how do you do it?

 

[Adam_151]

Bare pyro on the brick surface? if you want more than just a single double socket (which you can back onto a single socket in the lounge)

 

[Lectrician]

A cable can be clipped tight to the inner skin of the cavity if it is done as the wall is built - I have done this a couple times. You need to liase with the builder to ensure the outer cavity wall is not built to complete height, and that the inner walls morter has dried. Liasing like this can be difficult.

Remember, cables in cavities are not permitted as drawing them in can damage them (not if clipped as I say), and you musn't bridge the cavity (you wont if clipped as I say).

 

[Lectrician]

Bare pyro on the brick surface? if you want more than just a single double socket (which you can back onto a single socket in the lounge)

Common to run pyro in the morter course in pubs etc to feed wall lights - brick walls, and random sized stone walls.

 

[comms]

how would you run cables in a conservatory which is going to left be brick faced, I've never wired a conservatory, I fully understandthe cables in cavity is not allowed but how do you do it?

Surface mounted sso's with trunking direct on unplastered dwarf walls (imho looks crap). Or mount the trunking to underside of window board overhang then drop down into surface mounted sso's (looks better).

Used D-line trunking around skirting surface mounted sso's above skirting (not too bad)

mic (mims) clipped along mortar lines looks tidy but if your not practised at installing this stuff it can look like a black art if you know what i mean.

By far the best way is to get the customer to dot/dab the walls after you've been in, you can clip direct & mount the back boxes unsunk on to the brick work.

Extend existing ring from nearest socket by crimping, then fuse spur to lighting.

Or

I've run swa from switch fuse off split tails at front of property, around outside of property into new cu inside conservatory, supplying radials for sso's & heaters + internal & external lighting. Cu with 30mA rcd main switch or rcbo's for circuits.

Avoid running cables behind conservatory plastic trims such as along ridge for lighting or fan), been to a few faults where this has been done causing chaffed cables. I tend to use 20mm white pvc conduit on snap saddles mounted to the ridge trim to run a supply for overhead lighting or fan if requested by customer.

Not to proud about it but I've run cables in the cavity on one or two occasions, but insisted that no insulation is used in the cavity afterwards. You could fall foul of building regulation C (i think )if this method is used.

 

[RF Lighting]

What about running a 4.0mm² split con round the outside?

Not the best soloution by far but worth considering?

 

[wesj]

Thanks for all your replies they make good sense,but the sparks who walked away from the job said part P regs stopped him , or stated that you could not have one area supplied by 2 circuits. Is this correct as my customer needs to have the work certified. Many thanks. Wes

 

[Lectrician]

As I have said - no problem with that.

 

[wesj]

Thanks Lectrician sorry I made you repeat yourself. My customer has found a sparks who will carry out the works and certify but he did comment that although he agreed with yourself that he did not think it was in any regs not to come off 2 circuits for one area, the other sparky had some sort of logic in that a fool might turn off the MCB and assume the whole area was isolated. I wonder was this some old reg, the 1st electrician was senior in age. thanks again. Wes

 

[RF Lighting]

It is not a regulation to keep all the sockets in one area on the same circuit, but it certainly is good practice.

I would be tempted to put a small warning or circuit identifier sticker on the sockets.

 

[kevnurse]

I would label the 2 cbs in the CU