1.0mm cpc on a RFC - allowable?

[electricAl]

Altho` i`ve got it in me head that 1mm cpc in a Ring Final is no longer permitted, i can`t seem to find a definitive answer.

Can anybody help me out here please...

 

[vardymr2]

What size is the phase and neutral?

 

[electricAl]

Perhaps i shouldn`t have assumed it`d be obvious

For the record - 2.5mm / 1.0 mm found thruout a RFC in T & E on a domestic Periodic.

Altho` the ring in question passes an adiabatic i`ve long been of the mind that 1.0mm is no longer permitted. However, in looking for something to substantiate i`ve come up with nothing but speculative assumptions. Was looking for something definitive - preferably a Reg (altho i`m pretty sure there aint one or some other reference in Guidance Note or similiar form).

I`m getting the feeling this could be one more of those unwritten rules that many of us abide by but isn`t actually stated...

 

[vardymr2]

If your doing a periodic then it will pass cause its only a code 4 as it doesnt meet todays regs but when it was installed it will of met the regs at the time, To be honest i have not heard of 2.5/1.0mm twin and earth and im pretty sure its not on the market now.

 

[electricAl]

If your doing a periodic then it will pass cause its only a code 4 as it doesnt meet todays regs but when it was installed it will of met the regs at the time, To be honest i have not heard of 2.5/1.0mm twin and earth and im pretty sure its not on the market now.

Not for a long time - but there again, i wasn`t looking to buy the damn stuff... i`ve only just got shut of the last lot

I was trying to get exactly what i asked for - a pointer towards some definitive answer as to it`s unpermissability or otherwise. I take it you don`t know, then.

As to your assertion that if it once met the regs then only a code 4 is called for, i would suggest you`re oversimplifying an often complex subject. I never assume because something`s been installed that it `must` have met the regs of the time, & in any case, there are instances where a once permitted situation would warrant worse than a code 4 under current guidelines.

Each non-compliance should be considered on it`s own merits...

 

[sparks1234]

come across some of it only this week, if the Zs readings are ok then no worrries

 

[vardymr2]

Well lets look at it this way. Say u did a periodic on a 15 year old installation and the bonding to the gas and water were in 6mm would u pass or fail this test?

 

[electricAl]

come across some of it only this week, if the Zs readings are ok then no worrries

Yeah, my thinking was heading that way...

& the Zs are all okay (big little r2 tho!)

But you don`t know of anything stated either mate? One of those `bugging yer` kinda of queries - started off determined to find an answer but am losing motivation to persevere now

Well lets look at it this way. Say u did a periodic on a 15 year old installation and the bonding to the gas and water were in 6mm would u pass or fail this test?

I`d neither pass nor fail it. I`d mark it down as an appropriately coded non-compliance with current regulations.

What would you do?

 

[flukey]

on site guide states minimum cpc for an A1 ring and A3 radial as 1.5mm2.

however if your adiabatic and zs are fine i would just code 4 it

 

[andyb]

It's in the BRB appendix 15, page 362.

So not realy a reg to quote, just guidence.

 

[Tester Steve]

Yep, code 4 for me!

Steve.

 

[Des 56]

I think the note in app 15 gives an example only of reduced cpc and stays clear of actually stating 1.00mm for a 2.5mm is non compliant,leaving that bit to ourselves

These last couple of editions gives advise on ways of complying rather than thou shalt do this or do that, therefore leaving these sort of judgements to us

Your last decision seems the right aproach to me

 

[madmaz]

The 1.0mm cpc is not permitted on a BS 3036, as long as Zs is oke its permitted with any other fuse type

 

[roukel01]

Once upon a time The Part P Document said a Ring containing a 1.0mm CPC should either be rewired or an RCD installed for additional protection.

However, the latest document (Page 38) states that in these cases a competant electrician should be consulted about upgrading the circuit or changing the consumer unit (Where protection is by a 30amp re-wireable Fuse)

 

[Jimwax]

A bit of history here 2.5mm T&E with 1mm cpc was the original metricated cable that replaced 7/0.29 T&E which had a 3/0.29 CPC although it was not called that! When we went metric 1969/70 the 2.5mm was what we got.

On Periodic Inspection you are supposed to assess the age of the installation and make appropriate comments.

You won't design or install such cables today but if the circuit is in good condition and not compromised with extensions etc then it should be graded as a cat C3 if at all - since we no longer have "doesn't comply with the latest edition of the regs" There are a alot of Ring Circuits out there cabled in this stuff.