EICR Code for two circuits on one cable.

[Slewis120]

Hi,

Currently undertaking an EICR on a factory, we have came across an 4 core SWA and 4 Core SY which have been split in the DB to serve two separate circuits. The SWA has the Brown on a 10A MCB and the Grey is on a 16A. So clearly they have shared earths and shared neutrals, similar scenario with SY. What code fault would you put this down as?

 

[davesparks]

Have they definately got a shared neutral between the 2 circuits on the SWA?
Normally when using a 4 core SWA for 2 circuits there would be 2 lives, 2 neutrals and a shared CPC (the armour) which is fully compliant.

However with a 4 core SY (assuming that is 4 cores total not 4 cores plus earth) that is obviously not possible.
If they have used a shared neutral between 2 circuits I would code it C2.
They may alternatively have connected the cores as seperate neutrals and used the braid as a CPC which is also unacceptable and would attract a C2 code.

 

[Slewis120]

With the SWA being on two separate phases and different size MCB’s surely that can’t be compliant. We haven’t traced the cable as of yet but presume it goes to a Joint Box.

 

[westward10]

Providing the circuits are electrically separate including the neutral conductors and the insulation of the conductors is rated for the highest voltage then it is fine.

 

[pc1966]

With the SWA being on two separate phases and different size MCB’s surely that can’t be compliant. We haven’t traced the cable as of yet but presume it goes to a Joint Box.

If it has a 'borrowed neutral' (common N to the two circuits) then it is C2 no matter what, as above.

It should be labelled as having more than one point of disconnection at either end.

Otherwise it is not elegant, but you see multiple singles in conduit doing much the same idea.

 

[davesparks]

With the SWA being on two separate phases and different size MCB’s surely that can’t be compliant.

Why can't it be?

There's nothing wrong with using one cable for multiple circuits.

 

[davesparks]

It should be labelled as having more than one point of disconnection at either end.

I don't think there's any requirement for a cable carrying multiple circuits to be labelled as such, only equipment which cannot be isolated from a single device.

Otherwise it is not elegant, but you see multiple singles in conduit doing much the same idea.

It can be an elegant soloution. Working in theatre/stage lighting circuits are usually in multiples of 6 so it is quite normal to use muticore SWA to carry multiple circuits to the same place.

 

[Lister1987]

I would go with an FI until you can put sufficient resources to identifying the conductors and feed arrangements for the circuits. This will have the same end result as a C2 and would give an unsatisfactory EICR. You could add into this "Unsatisfactory pending further investigation of circuit wiring for circuits X"

 

[westward10]

There is nothing to investigate.

 

[Intoelectrics]

Hi,

Currently undertaking an EICR on a factory, we have came across an 4 core SWA and 4 Core SY which have been split in the DB to serve two separate circuits. The SWA has the Brown on a 10A MCB and the Grey is on a 16A. So clearly they have shared earths and shared neutrals, similar scenario with SY. What code fault would you put this down as?

You need to identify what the situation is before you can apply the correct code (if one is required at all), else your report maybe inaccurate, if not it may require further investigation. Is your statement (my bold) an assumption or verified as true?

As westward10 stated - "Providing the circuits are electrically separate including the neutral conductors and the insulation of the conductors is rated for the highest voltage then it is fine".

 

[davesparks]

I would go with an FI until you can put sufficient resources to identifying the conductors and feed arrangements for the circuits. This will have the same end result as a C2 and would give an unsatisfactory EICR. You could add into this "Unsatisfactory pending further investigation of circuit wiring for circuits X"

There's nothing to be investigated.

FI is not the same as a C2 and it doesn't give the same result.

 

[Lister1987]

There's nothing to be investigated.

FI is not the same as a C2 and it doesn't give the same result.

Am Sure Section F used to include FI as a condition that would fail an EICR, must have changed this edition?

 

[westward10]

Am Sure Section F used to include FI as a condition that would fail an EICR, must have changed this edition?

But what needs further investigation.

 

[davesparks]

Am Sure Section F used to include FI as a condition that would fail an EICR, must have changed this edition?

That hasn't changed, but that doesn't make it the same as C2.

 

[DPG]

I think what Lister is getting at is that the OP hasn't confirmed if the neutral is shared between the 2 circuits. That's what needs further checking.