MAximum Cable Length for a Ring main?

[dave12]

Ok Just after a little advice please,

Ive just discovered my kitchen socket ringmain supplies all of the upstairs sockets too (all be it 5 sockets). The other ring main feeds a massive wait for it....... 3 sockets in the living room!

So I want to run the upstairs and kitchen off seperate rings. To do this in the kitchen I need to run a cable from the consumer unit (living room) up to the loft then across the house and down into the kitchen, so before I even reach a socket I will have about 25m of cable plus another 25 for the second cable making the ring, is this ok? Is there any restrictions on cable length?

Thanks

 

[mapj1]

The first restriction on cable length is usually voltage drop, which, from memory ends up being equivalent to a total circuit length of about 50 to 60m of 2.5mm (the normal ring main cable). try the TLC website online calculator, or the cable selector in 'for reference' for the definitive answer.
If you are nowhere near this then its not a problem. If its marginal you may have to be cunning.
regards M.

 

[Thermo]

what like creep up on it or lie to it?

 

[AliasOmega]

I always thought that the maximum ring main length would not exceed 40metres.

The kitchen would have its own ring main, the downstairs and upstairs would be on the same ring main.

I was a apprentice electrician from 1996 - 98, then full time from 98-00 till i joined the RAF.

Need any advice, feel free to throw it my way.

Alias

 

[ban-all-sheds]

Buy a copy of the On-Site Guide - has tables of that sort of info.

 

[Albert]

Buy a copy of the On-Site Guide - has tables of that sort of info.

I think that this is the most practical advice (about £16.00, look for the brown one), as there you will find with the Volt drop tables (formulas) some 'factors' to be considered while calculating your circuit, which in some cases might be significant I don't think that the number of sockets will make a difference, what makes the difference is what the sockets are used for, you could use 10 sockets with bed lights and demand max. 500 watt or use one socket with a hoover or a portable electric heater etc. and load it with 3000watt or even more...and so on.
As you are going to make these changes, I would think that you could separate the down stairs from the upstairds, and may be put an RCD on the downstairs (if you don't have one already).
good luck
Albert