Loft socket - can I take a spur from THIS?

[wywywywy]

Hi all,

So background info first... I live in a top floor flat, with full access to the loft. And I want a spur to go to the loft.

Basically I would like a double socket (or may be more) in the loft, to power these:
- Projector (ceiling-mounted) in the living room
- Projector screen (ceiling-mounted) in the living room
- A table lamp in the loft, when I go to the loft I will at least have some light
- LoftBox in the loft, in the future

The peak requirement will be around 500w or so.

However, here comes the problem. All the ring main wiring are done under the floor, and chasing the walls is not an option at the moment due to the disruption and the costs.

In the loft, the only wiring running are the lighting circuit, and the electric shower circuit. Obviously I cannot legally or practically tap into the lighting circuit, so I am thinking about the electric shower circuit.

The electric shower circuit is of 10mm2 wiring, going to a 10.5kW electric shower. It has its own MCB and also an RCD in the consumer unit. Basically it goes from the consumer unit, to a pull cord switch in the bath room, to the electric shower.

So, can I spur from this circuit (with a junction box) in the loft before it goes to the bathroom? And should I use a 5A fuse instead of a 13A fuse?

Finally, is it notifiable?

If there is any way to spur from the ring main without having to tap into the shower circuit, I will be very happy to consider.

Any advice welcome!

Thanks.

 

[CAWORK]

No. It wouldn't be advisable at all.

 

[davy_owen_88]

Find somewhere discreet for some trunking and extend the ring circuit up to the loft in that. Spurring from the shower circuit is a massive no no.

 

[DESL]

You can spur off the lighting circuit via FCU with a 3A fuse providing the maximum demand for your upstairs lighting and projector kit does not exceed rating of fuse/MCB at CU.

If you have loads of down lighters upstairs then the only way will be to extend ring main.

If you have an airing cupboard or built in wardrobe you could extend ring main into loft by routing cable through either.

Or use some of this http://www.tlc-direct.co.uk/Products/DL2D30QSW.html

 

[sparkmanc]

Find somewhere discreet for some trunking and extend the ring circuit up to the loft in that. Spurring from the shower circuit is a massive no no.

Not sure on the regs on this one but I can't see anything wrong with maybe feeding a small consumer unit from the Shower Circuit.

 

[sanj.varah]

couldn't he run the *hopefully* 10mm^2 cable into another consumer unit then split the load there? one for the shower and one for the sockets.

I haven't seen this done in a house but i have seen it done in a garage where the guy had some rather large electric heaters running off a garage CU. Garage CU was in turn being fed by SWA from the CU inside the house.

 

[wywywywy]

Hi,

Why is spurring from the shower circuit not advisable? It is because of the potential load can exceed the rating of the wires? Or not?

It is a small open plan flat, so I don't have anywhere discreet to hide trunking... (no airing cupboard and even the wardrobes are open plan).

Oh by the way I know about that trunking, in fact I use it all throughout the flat instead of skirting boards.

Thanks.

 

[sanj.varah]

The breaker on your shower circuit will probably be around 40A, that is significantly higher than the load you would get from your circuit, thus it would not provide sufficient protection in the event of a fault.

 

[CallEdsFirst]

The breaker on your shower circuit will probably be around 40A, that is significantly higher than the load you would get from your circuit, thus it would not provide sufficient protection in the event of a fault.

Not that anyone is advocating this, but the circuit would obviously have to be fused down suitably at the spur. No one is suggesting running one double socket off a 40a (hopefully bigger for a 10.5kw) shower circuit!

I'm hypothesising here, not suggesting. Almost hijacking the thread to ask my own questions!!!!

Depending on how the 10mm is run, it could carry up to 63A. Why not forget its a shower circuit to be spurred off, but turn it into a submain, uprate the MCB at the board, run it into a CU in the loft, perhaps an RCBO for the shower circuit for discrimination, and a suitable second MCB for the circuits in the loft. Nothing reg breaking that I can see. Shout me down at will!

 

[davy_owen_88]

Because that would turn is a simple, non-notifiable job into a more complicated, notifiable job. Installing a new CU and then 2 'new' circuits is also going to be more expensive even before you add on the BCO fees.

I still stand by more original advise, get some trunking and extend the ring circuit up into the loft.

 

[CallEdsFirst]

Well its cost or disruption. I dont think that this need be an expensive job. There is no additional "making good" costs associated with an entirely new circuit and the required decorating, and its plausible.

The alternatives are:

1. No power in the loft
2. New circuit and make good.

No one specified that the solution had to be non-notifiable, just clarification of whether any proposal was or wasn't! Perhaps that is my failing. I didn't state the Part P implications.

 

[davy_owen_88]

I'm not denying that it is plausible, just that it's more expensive in the long run and probably just as disruptive.

If a bit of chasing and some plaster is too disruptive/costly then factor in the problems the BCO inspections will make along with the fees they expect... Suddenly some butt-ugly trunking is looking like more attractive solution when the OP can buy what he needs at B&Q and get the job done in a day for less than £20 (ish).

 

[CallEdsFirst]

Scheme electrician = no BCO visits, safe job benefits ad infinitum.

 

[sanj.varah]

while i can't condone such activities. Why don't you just do it and not notify?

I often think that I do a better job than most trades people because it is my house and I have to live in it.

While I appreciate that electricians have to go through city and guilds and exams XYZ to qualify, any tom dick and harry with half a brain could pass those exams in a week (and many do!), so in my humble opinion its not worth the paper its written on.

As an example, just hoovering up under floor joists - while this might sound trivial to some people, I value it. Also taking up enough floor boards to ensure the cables are clipped every 600mm and not just dangling along the plasterboard - takes time but I bet most of the qualified lot out there don't do it.

I guess this is opinionated and that was mine.

 

[kevnurse]

I wouldn't spur off any high load cable (cooker or shower) because it would mean terminations in the high current wires inside a junction box, somewhere. If the screw in the the terminal doesn't sustain proper and full contact with the wire throughout its life, there will be localised heating in that terminal block while the high load appliance is switched on. Just my tuppence worth....