electrics......wiring a spur

[jandrews]

Hi all
A spur taken of the 32 amp ring main, does it have to be 2.5mm or 4mm cable? Surely if you use 2.5mm, then plug 2 things rated 3kw in to the spur, asuming your spur is a 2 gang you will over load the cable. If you use 4mm cable then could you have two, 2 gang sockets?

Thanks James

 

[Adam_151]

2.5mm² is the norm, 2x13A loads will overload the outlet as welll!

the problem with using 4mm² for multiple unfused spurs is that you end up with the increased possibility of asymmetric loading on the ring final circuit, which is why you won't find it as any standard arrangement

 

[briwire]

It has to be 2.5mm. You are right in what you say, but it assumes that you won't have two 3kW appliances plugged in at the same time. It's one of the perculiarities of our ring main system I'm afraid.

 

[ColJack]

2.5mm ref method 1, clipped direct ( IE plastered into a wall or nailed to it.. ) is 27A..

2 x 13 = 26A...

 

[Spark123]

2.5mm ref method 1, clipped direct ( IE plastered into a wall or nailed to it.. ) is 27A..

2 x 13 = 26A...

Just be a little bit carefull as some double sockets are only rated at 13A between the two outlets. Higher quality sockets may be OK for a continuous rating of greater than 13A but I wouldn't recommend it!! Also see Big_Sparks post:
http://www.diynot.com/forums/viewtopic.php?p=42047#42047