16mm t+e sub main

[Mike Watters]

periodic report says it's inadequate. was installed 10 years ago. 60 amp rewireable fuse protects the cable. the main supplies a small bed sit with 1 x lighting circuit, 1 x 32 amp radial socket circuit and 1 x cooker circuit that has a 3kw cooker. a new wylex consumer united was fitted 2 years ago. why would it be ok 2 years ago and not now.

 

[Mike Watters]

4 got to say, lights on rcbo, cooker and sockets on rcd side of board.

 

[SimpleSimon]

Sounds fine to me. So they think its undersized? When you say sub-main is it coming from a main.board somewhere else?
Use diversity or clamp it to prove 16mm is certainly enough.

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[Groucho Mace]

How long is the cable run?

 

[Rockingit]

Not got the book to hand but from memory 16mm is good for something like 99A, so backed by a 60A CPD I can't see an issue at all.

 

[Mike Watters]

20 meter run from main csu. is the 6mm cpc good enough and if not why would the lad who fitted the board not add another cpc, errrrrr

 

[brman]

from the OSG 16mm is good for 85A if clipped direct but goes down to 42.5A ref103 so I think it depends on the installation method.

I think we need more info, for example Ipf, to work out if the 6mm2 cpc is good enough.

 

[SPARTYKUS]

Bet its nearer 99A if on cable tray

 

[nickblake]

All depends on the installation method the current carrying capacity can range from 42.5 to 85 amps plus obviousley the cable length

 

[telectrix]

might just be that it's been classed as undersized for the cpc, not the L/N.

 

[SPARTYKUS]

115.

Thats the highest I can find for 16mm2 multicore, but thats assuming its entire length is soaked in liquid helium.

 

[PC Electrics]

The bedsit might need main protective bonding if it's seperate from the house, in which case the 6mm cpc isn't adequate.
Does the report say anything about this?

Does the report say anything about how the 16mm is installed (or can you tell us)? Mainly we need to know if it runs through any insulation or is otherwise enclosed.

If it's surface clipped or buried direct in plaster then 85A x 0.72 3036 factor = 61A, so OK.

 

[SimpleSimon]

What is the PFC of the board? Use adbiatic to see if it works out fir the 6mm earth.

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[Mike Watters]

partly in plastered partition walls,under wood floors. why is rcd protection not needed for the cable?

 

[Rockingit]

115.

Thats the highest I can find for 16mm2 multicore, but thats assuming its entire length is soaked in liquid helium.

Does that mean the electricity comes out squeaky?

 

[Rockingit]

I put a 16mm T&E into a bungalow last week to facilitate a board relocation - original 16mm tails now go to a DP iso, then run to the new board via 16mm TE clipped to the loft joists. I just ran a 10mm earth alongside it from a new MET, so effectively giving it a 16mm earth as well. Cut-out is only a 60A (1 bed bungalow) so I have no problem with it all being 16mm not 25mm.

 

[jase]

maybe they are getting things mixed up cos it is supplying a board and they think all tails have to be 25mm with a 16mm earth???

 

[tony mc]

If its a Periodic or EICR it should explain what is inadequate and a suitable code attached to that observation.

What has been documented re the above?

What is the earthing arrangement for the premises?

 

[GLENNSPARK]

If its a Periodic or EICR it should explain what is inadequate and a suitable code attached to that observation.

What has been documented re the above?

What is the earthing arrangement for the premises?

and while its all about "its this....its that"....the voice of sense comes forth......is it a "2"...or what?.....

 

[Mike Watters]

the report said code 1. disconnection times not met for fuse type. it,s a 3 phase tnc s, each phase supplying 3 studio flats