25mm split con sub main eicr code?

Bellendian · Jul 15, 2019

Just done an EICR on a domestic, the sub main running from origin to cu is 25mm split con. Hard to know if its more than 50mm deep in walls etc without intrusive investigation. So could run with FI, but obv that doesn't deliver a satisfactory report.
Bit of a tricky one as it would have complied with 16th, but the place appears to have been otherwise installed to 17th. Previous EIC 2009 plus dual rcd board. I'm leaning toward C3 but would like to hear opinions...cheers

Strima · Jul 15, 2019

C3 for me.

buzzlightyear · Jul 15, 2019

me has well so thats c3 then .

Dave OCD · Jul 15, 2019

I'd have to go with C3 too, but protecting this sub main at source with a 30ma RCD would also make it non compliant.

Bellendian · Jul 15, 2019

Dave OCD said:
I'd have to go with C3 too, but protecting this sub main at source with a 30ma RCD would also make it non compliant.

Exactly....that's my dillema...what is the 'improvement recommended'?
Split con conforms to BS7870, so we're not into SY/CY arguments, only change so far as I can tell, was that it was delisted as being suitable for being buried in building fabric less than 50mm deep without additional protection.
So a couple of test holes in plaster to prove depth, results in no code at all, no improvement required, and all is well?

snowhead · Jul 16, 2019

It may well be in the Cavity,,Unsupported..

davesparks · Jul 16, 2019

It's unlikely to be greater than 50mm deep if it's chased in, so I'd assume it doesn't comply with current regulations.
The problem is that it doesn't have a complete armour layer connected to earth, most of the concentric layer is connected to neutral. So ordinarily it will function in the same way as far as preventing metal objects penetrating the cable from becoming live. However it is not technically compliant and you could argue that its possible there could be a neutral fault at the same time as someone hammers a picture hook into the cable.

I agree with the others that it should strictly be a C3, but I don't think it would be practical or economically viable to improve this considering how small the actual practical improvement would be.

davesparks · Jul 16, 2019

Bellendian said:
Exactly....that's my dillema...what is the 'improvement recommended'?

Replace with SWA or add an earthed metal plate over the cable to protect it.

Taylortwocities · Jul 16, 2019

davesparks said:
Replace with SWA or add an earthed metal plate over the cable to protect it.

That’s the remedial process. We are talking about the correct EICR code.
Per the above C3 is the kiddy.

Bellendian · Jul 16, 2019

Thanks, C3 it is....forever! Can't see this one being fixed for a few years yet!

davesparks · Jul 17, 2019

Taylortwocities said:
That’s the remedial process. We are talking about the correct EICR code.
Per the above C3 is the kiddy.

The post I was replying to asked specifically what the improvement that is being recommended is.

Deleted member 26818 · Jul 17, 2019

Unless BS7671 prohibits the use of split con for domestic use, no code.

DPG · Jul 17, 2019

spinlondon said:
Unless BS7671 prohibits the use of split con for domestic use, no code.

It's buried in the wall

Deleted member 26818 · Jul 17, 2019

DPG said:
It's buried in the wall

It has an earthed sheath.

Ian1981 · Jul 17, 2019

spinlondon said:
It has an earthed sheath.

Not fully encasing the cable it doesn’t.
This will not comply with 522.6.204 indent (i )
Split con does not incorporate an earthed metallic covering which actually covers the entire cable

DPG · Jul 17, 2019

spinlondon said:
It has an earthed sheath.

Mmm, not convinced.

westward10 · Jul 17, 2019

At one time split concentric was deemed suitable for being in a wall without additional rcd protection but was removed in the one of the amendments to the 16th Ed.

Ian1981 · Jul 17, 2019

westward10 said:
At one time split concentric was deemed suitable for being in a wall without additional rcd protection but was removed in the one of the amendments to the 16th Ed.

So was twin and earth

westward10 · Jul 17, 2019

Ian1981 said:
So was twin and earth

Never realised that, not heard that.

Ian1981 · Jul 17, 2019

westward10 said:
Never realised that, not heard that.

Always willing to pass on my knowledge to those who need it

Deleted member 26818 · Jul 17, 2019

westward10 said:
At one time split concentric was deemed suitable for being in a wall without additional rcd protection but was removed in the one of the amendments to the 16th Ed.

The requirement to provide RCD protection for cables concealed in walls, was introduced in the 17th.
So nothing was removed in the 16th.

Deleted member 26818 · Jul 17, 2019

Ian1981 said:
Not fully encasing the cable it doesn’t.
This will not comply with 522.6.204 indent (i )
Split con does not incorporate an earthed metallic covering which actually covers the entire cable

The split concentric I’ve used does.
One half is neutral, the other half earth.
No gaps.

westward10 · Jul 17, 2019

spinlondon said:
The requirement to provide RCD protection for cables concealed in walls, was introduced in the 17th.
So nothing was removed in the 16th.

Quite correct error on my part. Nevertheless concentric was but no longer is suitable no matter it's construction.

Deleted member 26818 · Jul 17, 2019

westward10 said:
Quite correct error on my part. Nevertheless concentric was but no longer is suitable no matter it's construction.

No longer suitable for use in a domestic installation, or no longer suitable for use without RCD protection?

westward10 · Jul 17, 2019

In line with the thread topic, additional rcd protection.

Deleted member 26818 · Jul 17, 2019

Probably doesn’t comply, because the standards for con and split con are different to those for SWA.

Have heard in the past, that con and split con are prohibited by ESQCR for use in consumer’s installations.
Not sure if that is the case though.

davesparks · Jul 17, 2019

spinlondon said:
The split concentric I’ve used does.
One half is neutral, the other half earth.
No gaps.

Exactly, the live conductors are not fully surrounded by earthed metal, neutral conductors are classed as live conductors.

Also split con isn't normally half and half, it's normally at least 2 thirds neutral.

Deleted member 26818 · Jul 17, 2019

davesparks said:
Exactly, the live conductors are not fully surrounded by earthed metal, neutral conductors are classed as live conductors.

Also split con isn't normally half and half, it's normally at least 2 thirds neutral.

In the UK, the neutral is generally earthed at source, which is why ESQCR allows split con to be buried in the ground.

Ian1981 · Jul 18, 2019

spinlondon said:
In the UK, the neutral is generally earthed at source, which is why ESQCR allows split con to be buried in the ground.

As the regulation I posted states, it has to have an earthed metallic covering that completely encases the conductors, split con does not therefore unacceptable to be used for the purpose of burying in the wall without rcd protection , mechanical protection etc

davesparks · Jul 18, 2019

spinlondon said:
In the UK, the neutral is generally earthed at source, which is why ESQCR allows split con to be buried in the ground.

Yes, I'm aware it is allowed under ESQCR, and for all practical purposes it will be no different to SWA. However it doesn't satisfy the requirements of bs7671 as far as I know.