2core swa, not earth load end.. TT

[robo83]

Hi,

Been to a job with a 2core swa supplying the garage.. The swa has been glanded inside house to CU. But the other end in the Garage has had the swa run in plastic conduit with no gland on the swa so unable to test r1/r2.

However the garage has its own earth rod. So technically the swa is earthed from the house end, with the garage having its own earth rod.

The garage earthing TT is 37.0ohms, would I note this down as the garage r1/r2 circuit. Accepted with the 1667ohms as rcd?

 

[Midwest]

Is this an EICR, or are you doing some alterations/additions in the garage. What is the house supply?

 

[Pete999]

Is this an EICR, or are you doing some alterations/additions in the garage. What is the house supply?

Do you mean R1+R2? r1 r2and rn are readings for RFCs (Ring Final Circuits)

 

[Midwest]

Did you mean to quote the OP Pete

 

[Pete999]

Did you mean to quote the OP Pete

Not sure what you are getting at Middy, just trying to say to the OP that r1 and r2 are readings for r1 Live and r2 Earth as a single conductors, I thought he was meaning R1+R2 or am I getting tangled up somewhere?

 

[Midwest]

Ohh okay

 

[jaydub]

Robo83, can you not get a croc clip on the armouring at all at the garage end? Then you could measure r1 + r2 this way? Midwest and pete, if that was possible, is that allowed?

 

[Pete999]

Robo83, can you not get a croc clip on the armouring at all at the garage end? Then you could measure r1 + r2 this way? Midwest and pete, if that was possible, is that allowed?

It's R1+R2

 

[jaydub]

I dont follow...

 

[Pete999]

I dont follow...

You are trying to measure the loop of the L and E conductors correct? Which will give you a resistance reading noted as R1+R2 not r1+r2 a small thing but end to end reading r1 r2 and rn are recorded as RFC readings only, and are end to end readings of the L.N and cpc, get the basics wrong and other things will be wrong as well. Of course if you are insulating the armoring from the garage end why would you try and trying to measure the R1+R2 of the distribution cable.

 

[The Ghost]

the swa earth is not part of the garge earth so R1/R2 is gonna be between L and the Rod E. If I read you right?

 

[Octopus]

Robo83, can you not get a croc clip on the armouring at all at the garage end? Then you could measure r1 + r2 this way? Midwest and pete, if that was possible, is that allowed?

Hum.... Not sure what that would achieve.... Think about what you are testing

 

[Wilko]

the swa earth is not part of the garge earth so R1/R2 is gonna be between L and the Rod E. If I read you right?

My thought is the garage supply is a circuit off the main db (house CU) and this would have its own loop impedance from the SWA armour, which is its CPC. Then the sub board (garage CU) and the final circuits are the TT bit (?) .

 

[westward10]

He is trying to verify earth continuity to the armour of the cable which is not accessible as it is contained within pvc conduit to isolate it from the TT, this earth continuity is applicable to the circuit from the house and nothing to do with the TT.

 

[Midwest]

Perhaps we should just wait until the OP clarifies what he/she is doing?

Edit; job wise

 

[jaydub]

Wilko has interpreted what I was getting at lol

 

[The Ghost]

yeh but is it a circuit or just a piece of cable? Where is the loop hah!

 

[jaydub]

It would be a circuit wouldn't it, I guess it would be protected by an MCB in this scenario? I guess OP needs to clarify that

 

[Wilko]

yeh but is it a circuit or just a piece of cable? Where is the loop hah!

Well if it ain't a circuit how does current / fault current flow in it? Being creative, I'm thinking it's a >32A distribution circuit with a 5 or 1 sec disc time from 411.3.2.3 or .4 - at least it would be if I'd done it in 10mm

 

[The Ghost]

how does current / fault current flow

The MCB in the house protects the cable. The circuit in the garage is separate imho.