Lighting and sockets circuits

[akist]

Is it allowed to have just one wire going into each room, the wire then feeds the sockets and the lights in that room, and then at the fusebox I have fuses "room 1" "room 2" etc ?

 

[Sureitsoff?]

Problem is that the sockets would then be limited to only 6A. So, for example, when you switched the kettle on in the kitchen the power to that room would go off............

 

[akist]

I am thinking of the "lights" as a plug in upright lamp, or a bedside lamp, which you plug into the socket. Why can't all my lights in a room be exactly like that, using power from the sockets? That power is negligible, these days, and I would only need to run one single wire to each room that would power sockets and lights and whatever else is in that room.

Unless it is not allowed due to regs.

 

[EFLImpudence]

You could do that but then you would only have a socket circuit and no light circuit, wouldn't you?

 

[akist]

Yes, if that was allowed. Is it?

 

[EFLImpudence]

I can't imagine anyone has ever thought such a stupid thing would be done and therefore no one has ever bothered to make a ruling on the subject.

 

[Sureitsoff?]

If you had table lamps etc plugged into this cct that you propose, to switch a lamp on you would have to navigate a dark room to find the lamp to switch it on rather than the easier " normal" solution of having a switch by the door. There is nothing stopping you from having sockets for lamps etc that are controlled by a switch in a different position to the lamp sockets, after all if the room had a ceiling light you wouldn't expect to have enter the room and reach up to switch the ceiling light on!

 

[ericmark]

There is nothing to stop having a switched FCU for the lights, if we consider a caravan site, each caravan is like a small self contained room, with it's own 16 amp supply, however one big difference, the lights are battery powered as well, so loss of power does not plunge occupants into darkness. Of course we can get general power cuts, so whole house can be plunged into darkness.

But the rule book says:-
Every installation shall be divided into circuits, as necessary, to:
(i) avoid hazards and minimize inconvenience in the event of a fault
(ii) facilitate safe inspection, testing and maintenance (see also Section 537)
(iii) take account of danger that may arise from the failure of a single circuit such as a lighting circuit
(iv) reduce the possibility of unwanted tripping of RCDs due to excessive protective conductor currents produced by equipment in normal operation
(v) mitigate the effects of electromagnetic interferences (EMI)
(vi) prevent the indirect energizing of a circuit intended to be isolated.

Do you think that would be satisfied? the "take account of danger that may arise from the failure of a single circuit such as a lighting circuit" is the main bit, I would say loosing lights as you plug some thing in is not the time you can cope with loss of lights. Sitting in your chair when they fail is bad, but while your using some other electric equipment is not the time you want to lose lights.

Using rechargeable torches which auto light with a power cut can reduce the risk, this is what I have at top of my stairs, and the quote was from 2008 regulations, yet many had a single RCD feeding lights and sockets in the same room, which would it seems also not comply, but until the last few years use of all RCBO consumer units was rare.

This house like many from the 80's pre the RCD era, had sockets split side to side, reducing the loop impedance and meaning if the circuit failed, it did not need extension leads running up/down stairs, but the lights were split side to side, a little thought and it means you need at least three RCD's so sockets and lights for every room are not on same RCD, however many homes did have twin RCD consumer units fitted.

So yes one feed to sockets and lights, with a light switch being a switched FCU seems no worse than already done in many homes, but this house, 14 rooms when counting bathrooms and utility rooms, plus showers and cookers which clearly can't share supplies, so it would mean going from a 14 RCBO consumer unit to around an 18 RCBO consumer unit, and a complete rewire of the house, so it would simply not make sense.

 

[ericmark]

If you had table lamps etc plugged into this cct that you propose, to switch a lamp on you would have to navigate a dark room to find the lamp to switch it on rather than the easier " normal" solution of having a switch by the door.

Hey google turn on landing lights works for me, far easier than having to walk to light switch by the front door. I think the idea is daft, but do try to present real reasons why it should not be done. To my mind having switched FCU for lights you would still have a light switch in the normal place.

More to point is the habitation laws, it seems for a property to be considered habitable we need to comply with a list of rules, in Wales the new law for rented property has just come into force, since the Welsh and English is not the same, I don't know the rules for Surrey.

It may not breach electrical rules, but would need to read all the parts of the building regulations before I could be sure if it did not breach other rules.

So big question is why would you want to wire that way?

 

[RandomGrinch]

To my mind having switched FCU for lights you would still have a light switch in the normal place.

Or a non-switched FCU, and a conventional switch in a conventional place!

 

[EFLImpudence]

but do try to present real reasons why it should not be done.

The OP's proposal is to have a house with no lights - until someone plugs in some lamps.

To my mind having switched FCU for lights you would still have a light switch in the normal place.

So, you might as well have normal lighting circuits.

So big question is why would you want to wire that way?

Exactly.

 

[SUNRAY]

I have FCUs on the ring for under cupboard kitchen lights but not for the ceiling light.

It's something I've done a few times in sheds etc 16/13A feed and DSSO with FCU by the door with 1/2/3A fuse for light.

EDIT: At least no one is going to complain there is no such thing as 1 & 2A fuses

 

[Sureitsoff?]

Of course there is

1A to 13A Domestic Plug Fuse 25.4mm x 6.3mm BS1362 1A 2A 3A 5A 7A 10A 13A | eBay

Complies to BS1362. Fuse size: 25.4mm x 6.3mm.

www.ebay.co.uk

 

[RandomGrinch]

I have my loft lighting on an FCU off of the 16A radial up there.
So if I run my hoover and my welder at the same time, I'm likely to end up falling through the ceiling!

 

[Harry Bloomfield]

Or a non-switched FCU, and a conventional switch in a conventional place!

Or run say 2.5mm to the room as a 20amp radial, and wire lighting and sockets in 2.5mm. All of the accessories would then need to be rated to at least 20amp, or be provided with a local fuse.

You used to be able to source florescent fittings, with a built-in fuse, for large premises - where they might need to be on a 15 or 20amp supply, due to the sheer number of lighting fittings.