Length and route of tails from meter to consumer unit

Have a new build with meter box on outside wall.

What route and length of tails can I use going from the meter to the consumer unit (metal) and what route can it take - can it be routed through the exterior wall then around the corner of the wall in the cavity and then come out where consumer unit is or does it have to go straight through the wall to the interior and then along the wall to get around the corner to where the consumer unit is ?

You should probably ask whoever is going to test and sign it off . . .

The regs are designed to annoy us .  So we could go in the cavity as they would be more than 50mm deep , but encased in lagging so probably the tails rating is reduced to 3 Amps :innocent

You can go through the wall , then surface trunking to the board, thus avoiding the use of an RCD in the meter cupboard. 

Or up the inner wall in trunking & through the floor space . 

You are on site , what are your thoughts?

Welcome to the Forum by the way.

Evans Electric said:

The regs are designed to annoy us .  So we could go in the cavity as they would be more than 50mm deep , but encased in lagging so probably the tails rating is reduced to 3 Amps :innocent

You can go through the wall , then surface trunking to the board, thus avoiding the use of an RCD in the meter cupboard. 

Or up the inner wall in trunking & through the floor space . 

You are on site , what are your thoughts?

Welcome to the Forum by the way.

Click to expand...

Thinking of going internal trunking route - how long can the tails from meter to consumer unit be max without extra effort ?

ask your DNO

Gill Beechey said:

Thinking of going internal trunking route - how long can the tails from meter to consumer unit be max without extra effort ?

Click to expand...

What do you mean by that?

On my patch EDF won't allow tails to be longer than 3m. As for "in the cavity" - best give up on that too!

Murdoch said:

What do you mean by that?

On my patch EDF won't allow tails to be longer than 3m. As for "in the cavity" - best give up on that too!

Click to expand...

I just mean how long can they be - I thought it was 3m I just wanted to check ... in case it had changed.

as i said in post 5, ask your DNO. its their equipment you are relying on for protecting your tails, so its their decision for max length... or you could stick a switch fuse next to the meter and have any length tails you want

Andy™ said:

as i said in post 5, ask your DNO. its their equipment you are relying on for protecting your tails, so its their decision for max length... or you could stick a switch fuse next to the meter and have any length tails you want

Click to expand...

unless the DNO is EDF in Surrey and they won't allow the switched fuse!

probably have a max length of 500mm too

Andy™ said:

probably have a max length of 500mm too

Click to expand...

no - 3m max!

They will not allow any other equipment in the meter cupboard - so the way round this is to install a 2nd cupboard next to the meter one - you couldn't make this crxp up!

Yes I've come across this crxp too .  On a new build last year I had meter tails about 10 mtrs long from a meter cupboard.   So I fitted an 80A sw/fuse up in the top R/H corner + the tails .  The meter guy connected and went , only to be sent back next day because he hadn't fitted the DP switch .   I didn't expect it either as I'd supplied one , but no , must follow instructions . So two main switches !  Pathetic really.   

Oh and I noticed somthing odd with his earth connection so dropped it out to find this below.

Evans Electric said:

Oh and I noticed somthing odd with his earth connection so dropped it out to find this below.

Click to expand...

you mean something like test results you would expect from something with no earth?

I hadn't done any testing at that point , stooped to pick up something , looking up, the insulation seemed to dissapear into that Henley block terminal so I took it out .

Isn't this part of the new fail safe live testing, it minimises the chance of a shock whilst testing, otherwise we will be told that no live testing is permitted and results should be calculated. 

Saves all,that unecessary cable stripping and that stupid metal to metal,connection

who needs an earth connection anyway ?.......we are standing on earth :innocent

Evans Electric said:

Yes I've come across this crxp too .  On a new build last year I had meter tails about 10 mtrs long from a meter cupboard.   So I fitted an 80A sw/fuse up in the top R/H corner + the tails .  The meter guy connected and went , only to be sent back next day because he hadn't fitted the DP switch .   I didn't expect it either as I'd supplied one , but no , must follow instructions . So two main switches !  Pathetic really.   

Oh and I noticed somthing odd with his earth connection so dropped it out to find this below.

View attachment 7098

Click to expand...

Insulation piercing connections, what more do you want? There’s no pleasing some people!

Gill Beechey said:

Have a new build with meter box on outside wall.

What route and length of tails can I use going from the meter to the consumer unit (metal) and what route can it take - can it be routed through the exterior wall then around the corner of the wall in the cavity and then come out where consumer unit is or does it have to go straight through the wall to the interior and then along the wall to get around the corner to where the consumer unit is ?

Click to expand...

Just quoted a job. bit of power down the ye old summer house no big issue.  but have noticed meter box outside. front of main house. consumer unit at opposite side of house at rear. there is an mem double pole isolator before tails start. a cut off piece of 16mm earth hanging in there not  connected. then 2 x 6mm earths off met in parrelel . Hmmmmm just visual at present . don't wanna loose a nice little job. but dreading getting the test kit out. I always get em. so should we have a 80A kmf after the double  pole isolator here. to protect whatever is feeding the c/u . looks like tails. not had cu cover off yet. may end up running a 16mm round to c/u if test results come back lettuced on Ze. surely I can't take responsibility for that anyhow. I've not run these meter tails who and where they are routed is anyone's guess. 

Have you looked inside the house opposite side of wall? 

Yep. consumer up against ceiling. seems as though they drop down from ceiling. not back till next week have a proper jolly good look. long tails though very.