running 25mm tails - Electricians Forum | Electrical Forum | An electrical forum for electricians in the UK

bluecallum · 07-08-2008

Hi can someone tell me what the best way of running supply to cu from distributors supply if the run is more than 3 metres apart,as i have been told that you can only run 25mm tails no more than 3 metres,Thanks

07-08-2008

If the run is more than 3 metres you run your tails into a KMF switch (isolator) and then your tails out of the isolator to the CU can be as long as needed.

sparkymark · 21-08-2008

If this is a domestic situation we normally run out of the kmf in twin rather than tails.

PAUL M · 21-08-2008

Quote:

Originally Posted by sparkymark

If this is a domestic situation we normally run out of the kmf in twin rather than tails.

what size twin do you use to feed your db then?

sparkymark · 21-08-2008

well we protect it with a bs88 80A fuse, so when clipped direct we use 16mm (witha seperate earth) which will carry 85A before correction factors. What do you do then?

wait a minute, my mistake i should have said we protect it with a bs1361 type 1.

PAUL M · 21-08-2008

i allways fit a kmf 80amp,run 25mm tails out of that with 16mm earth,dont carry 16mm tails on the van.

ONIT · 21-08-2008

Eveing ALL,,

JUST WOUDERING IS A KMF A TPYE OF D/P ISOLATION IF SO WHAT DOSE KMF STAND FOR.

CHEERS

EasyFox · 21-08-2008

Quote:

Originally Posted by ONIT

Eveing ALL,,

JUST WOUDERING IS A KMF A TPYE OF D/P ISOLATION IF SO WHAT DOSE KMF STAND FOR.

CHEERS

This is a KMF
63 Amp TP&N Switch Fuse HRC

It's that sparky speak but in laymans terms all it is is a switch fused isolator

And for domestic
Wylex 100 Amp SP&N Switchfuses
or
SP&N Switchfuse

sparkymark · 22-08-2008

well those pictures are actually metal switch fuses. The term kmf is from an mem product number and now all similar non metal switch fuses are called a "kmf". This is what they look like.

www.alertelectrical.com/upload/pdf/753MEM800KMF.pdf