Convert radial (cooker) circuit to socket circuit

[Chi]

Hi all,

I need some advice from the above. At the moment I have an electric cooker/oven and thus the 32amp MCB and radial circuit. I've changing this to a full gas version and would like to convert the radial to a socket circuit (plug for cooker ignition, cooker hood and possibly another a doubel socket).

I have read diy books and posting here but there are areas I am not confident in.

1. Do I need to change reduce the MCB to a lower ampage. For example, to 20amp (and how is this done?). If I do change it to 20amp is the

6mm cable (I think) still suitable?

1. I'm likely to place a junction box or my first socket at the end of the circuit. To extend the circuit do I need to use 6mm or is a lower rated cable OK (for 2.5).

2. Is their a rule on how many sockets I can add and how far apart they need to be.

1. Anything else I need to think about?

Thanks in advance.

[usenet]

You have two choices for a 'conventional' radial circuit for sockets as specified in the IEE On-site Guide :-

20 Amp MCB and wire the rest of the circuit in 2.5sq mm T&E 32 Amp MCB and wire the rest of the circuit in 4sq mm T&E

Personally I'd go for the 20 amp MCB even though it involves changing the MCB as wiring with 4sq mm will be a pain. The existing length of

6sq mm is fine. To change the MCB you are best getting an MCB of the same type (i.e. manufacturer) as your existing CU. It should then be fairly straightforward to change it (with the power off obviously). The exact method for removing and installing MCBs can vary with different manufacturers.

See above, depends on the MCB in the CU. With a radial circuit you can branch it as much as you like which makes wiring very easy.

A radial circuit wired with 2.5sq mm T&E can supply up to 50 square metres floor area and there's no limit on the number of sockets. A radial wired in 4sq mm can supply up to 75 sqare metres floor area. There's no rules about how far apart sockets have to be.

Not really, except to label clearly on the CU that this is now a radial circuit supplying sockets. A similar note inside the box in the kitchen would be a good idea too.

[Christian McArdle]

You can keep the 32A MCB. I would, especially for a kitchen, where there are many power hungry appliances. You can spread the load by taking something big (i.e. washing machine) off the old ring and sticking it on the new circuit.

If you do change to 20A MCB, there are no problems with the 6mm cable. You are allowed to use bigger cable than necessary, if convenient.

This depends on installation details. 6mm (or even 10mm in some rare cases) may be required, but calculations will probably allow 4mm, depending on installation details. (i.e. a short distance clipped direct is allowed, but buried in insulation or in conduit may not be).

There are some limits to do with floor space, but they simply wouldn't apply for a kitchen. You'd have to be covering the area of a small size house to run into them, not a single room.

You can have as many sockets as you wish. Indeed, the latest on site guide gives guidance on how many sockets might be considered reasonable and you need quite a lot to meet their suggestions. The IEE are on a mission to reduce the number of multiway extension leads.

Christian.

[Chi]

Thank you all for the detailed replies. This clears up my uncertainties and I should be prepared for the job.