Log cabin 6mm 4 core swa

[sparcktikus]

Hi
Tncs system
Log cabin 25m from house
See that when exporting earth 10mm earth is the prerequisite so would it be ok to use 4 core 6mm swa and double up 2 cores effectively making 12mm for earth.
And understand the need for non combustible in house ie metal consumer unit but how about plastic consumer unit in log cabin which would preferable.
Thanks

 

[EFLImpudence]

It's not a prerequisite that the CPC (Circuit Protective Conductor - earth wire) to a log cabin must be 10mm² but

depending on the circumstances and supply earthing type you may have to have a 10mm² Bonding Conductor from the cabin to the supply Main Earthing Terminal - for which you could use a 10mm² CPC.

Anyway - yes you could use two conductors and there is also the armour.

 

[Taylortwocities]

Oh yes, the armour. Who’d have thought of earthing that?

 

[Notch7]

I have read that some electricians prefer not to use the steel armour as the CPC because if the sheath gets damaged, the steel rusts.

 

[EFLImpudence]

That, presumably, could also be an argument for not using SWA at all.

 

[bernardgreen]

An alternative to exporting the Earth is to have a TT system in the log cabin with a ground rod providing the local ( cabin ) Earth.

The armour of the SWA would need to be connected to the MET in the house but isolated from the CPC ( Earth ) in the cabin.

An RCD should be fitted in the cabin supply in the cabin.

 

[bernardgreen]

That, presumably, could also be an argument for not using SWA at all.

The armour needs to be connected to the MET ( or other effective Earth ) just in case the cable gets cut or spiked by gardening tools.

 

[AndyPRK]

If you use a metal CU, it will be easier to terminate the swa to it.

personally I would leave the 4th core spare.

 

[ban-all-sheds]

See that when exporting earth 10mm earth is the prerequisite so would it be ok to use 4 core 6mm swa and double up 2 cores effectively making 12mm for earth.

What does the electrician designing, installing, testing, certifying and notifying the work think?

And understand the need for non combustible in house ie metal consumer unit but how about plastic consumer unit in log cabin which would preferable.

1) Why would it be preferable?

2) Do you not think that your log cabin counts as domestic (household) premises?

 

[donrkebab]

I have read that some electricians prefer not to use the steel armour as the CPC because if the sheath gets damaged, the steel rusts.

They are not electricians, just cheapskate bodgers that don't like doing the job properly

 

[donrkebab]

Hi
Log cabin 25m from house

You should also consider data/phone wiring

 

[EFLImpudence]

The armour needs to be connected to the MET ( or other effective Earth ) just in case the cable gets cut or spiked by gardening tools.

Yes, I know - but if rusting is a reason for not using it as a CPC or bond, then it is also a reason for not using it as the protection for being spiked by tools.

 

[winston1]

Hi
Tncs system
Log cabin 25m from house
See that when exporting earth 10mm earth is the prerequisite so would it be ok to use 4 core 6mm swa and double up 2 cores effectively making 12mm for earth.
And understand the need for non combustible in house ie metal consumer unit but how about plastic consumer unit in log cabin which would preferable.
Thanks

Why do you want a CU in the log cabin? Sockets can be run direct (using the MCB in the house) and lights via a switched FCU.

 

[chivers67]

Really?!? The 6mm needs Terminating into something at the Cabin

 

[winston1]

Really?!? The 6mm needs Terminating into something at the Cabin

How about a switch or large junction box.