Radial Circuits Ask questions and find answers to many subjects relating to electrics and electrical work

[billinge]

Quick question really,
is it ok to wire two radial circuits within a small room from a consumer unit?
I've got a small 63A consumer unit in a littlish room, way under the 50m2, with three mcbs, one for power which is in a radial, but one set of sockets are to one side of the consumer unit, the other are the other side. Rather than running a cable to the first set of sockets then back to the remainder, or using a ring circuit, or a second mcb circuit, is it ok to use two cables from the one mcb, a bit like a ring with the middle missing I guess?

I can't find anything in the regs that say you can or cannot do it..?

thanks
Billinge

[ericmark]

Yes you can and the regs you need are on net as free down load as there was a mistake in the new regulations which was corrected so if you go to http://www.theiet.org/publishing/wiring ... m?type=pdf you can download the correction and go to pages 3 and 4 and it's all laid out in nice easy way. Do ensure to match the cable to MCB correctly radials are normally 20 amp there are now new cable types which do allow more but normal PVC twin and earth is 20 amp on radial.
Eric

[billinge]

Thanks ericmark,
as you've been so helpful, could you help me on one further query relating to lighting circuits;
I know you shouldn’t switch neutrals in light switches, but can you pass a neutral through a light switch. ie take the Live, Neutral and Earth to the switch, effectively daisy chaining switches together feeding the lights off direct, avoiding the use of ceiling roses? I didn’t think neutrals could go through switches at all…?
thanks
Billinge

[ericmark]

Where extra low voltage lights are used there seems to be two common methods one is to use a junction box which is sometimes criticised as unless you use the special spring clip type junction boxes should be accessible. The other is in the switch which also causes problems because of depth of box I would not say either is right or wrong. As to switching neutrals it is OK if switched with live. This is common with grid switches common with kitchen appliance supplies. I stand to be corrected but I don’t think it is against any regulations. However you will see in this forum how we instruct people by following standard practice and if you do your own thing although not against the rules it can may future repairs hard. If you do something non standard make a note of what you have done and put it in a document pocket near the consumer unit so in the future someone can see what you have done.
The rules and regulations are complex and I would not think anyone knows them all and all electrical things have some danger just make sure it is no more dangerous once you have finished.
While talking about regulations I assume you are aware of Part P and it’s requirements if not there are links in projects section.
Eric

[sparx]

Hi, just to confirm, it is quite in order to loop Neutrals in a term block in the switch box if there is room, I do it a lot using 'push fit' connectors which are very small & totally insulated.
Most 'Park Homes' are wired this way as wiring is then under floor not in tiny roof void, and bonus is only 1 cable at light fitting, much easier to connect 'fancy' fittings,
regards SPARX