2,5 16A Supply Cable Max. Length

[Deimos]

I need to run a new cable for a few standard sockets. However, the cable run is a fair way (not yet measured it). If running 2,5 for 16A is there a max. length of cable run before needing to use thicker cable ?

Also, I need to run a light supply as well. I had always thought that this should be on a 1,5 10A supply but was wondering if it could be put on the same supply as the sockets (seeing as I'm running the cable for the sockets anyway).

Many thanks

Ian

[Ford Anglia]

I'm no expert, so I'm not even going to try and comment on maximum lengths. I have some runs of over 15m of 2.5mm sq in my barn conversion, and the same for 1.5mm sq.

As for running lights and sockets off the same supply: you're not supposed to do it because of the different current draw from each, which means that each SHOULD have it's own dedicated MCB, IIRC 10A for lighting and16A or 20A for sockets. Don't take the current ratings as gospel, my books for this are in France, and I'm in the UK.

Have you thought of running a conduit, then putting single core cables in, one set for sockets, one for lights? You could then T off for either at suitable junction boxes.

[Nearly Retired (I am now)]

The longer the run the more cross sectional area you need and there will be limit to how far 2.5mm2 can go - I don't know how to calculate it.

If it's any help, when we had electricity installed in the barn (35 metres) away, the electrician ran a chunky cable to a new "submains" box in the barn from where he distributed the power and lighting circuits.

[fulcrum]

This website has a cable calculations table that should help..

http://www.repereelec.com/index.php?page=edc

[powerdesal]

Sorry, but I have just consulted my French textbooks and I cant find a maximum length. I would be interested to know the answer.

[Nick Trollope]

[quote user="Deimos"]

I need to run a new cable for a few standard sockets. However, the cable run is a fair way (not yet measured it). If running 2,5 for 16A is there a max. length of cable run before needing to use thicker cable ?

Also, I need to run a light supply as well. I had always thought that this should be on a 1,5 10A supply but was wondering if it could be put on the same supply as the sockets (seeing as I'm running the cable for the sockets anyway).

Many thanks

Ian

[/quote]

About 40M at 16A. Much further if you go for 4mm, but you won't get that into a socket (although you could go via a junction box).

& no, don't share lights & sockets.

 

[Deimos]

Many thanks.

Looks like I'll have to do a 6mm run for the bulk of the distance (for sockets) and a 2,5 for the lights to a junction box close to the room being supplied as (for the sockets at least) the total length (incl. drops to and from each socket) is 55m. Nowhere round here seems to sell 4mm cable - its all either 2,5 or 6mm. I'm keen of getting the cable stuff (U10002RV) as I don't manage pulling the cores through the gain particularly for longer lengths.

Given this I did think about running to a new fuse box but by the time I've put in a new breaker of the EDF thing (as you are not allowed to "branch" directly off the cable from the EDF stuff it would end up more complex and expensive than just running a 6mm for sockets and 2,5 for lights.

Ian