R1+R2 - two way lighting - 2.7 ohms, can i get your opinions please?

[telectrix]

no. you should have extended the equipotential zone, using the armour as cpc/earth. the only problem you'd have is if the garage has extraneous parts, you may need to run a separate 10mm bonding conductor.

 

[srl-8]

Leesparkkent - export earth (meaning, use the swa as a means of earthing. ) I have not used this and TT garage instead.

 

[srl-8]

How long is the 3c?

The 3 core is 10 meters

 

[trev]

And you expect that to introduce a substantial difference in your measurement?

 

[Leesparkykent]

Leesparkkent - export earth (meaning, use the swa as a means of earthing. ) I have not used this and TT garage instead.

then you would not be exporting the earth you would be extending the equipotential zone.

 

[srl-8]

Leesparkykent - sorry, thanks for clearing that up. Wrong term being used. The only means of earthing for the garage is a earth rod.

 

[srl-8]

Trev - No I don't expect that to make a massive difference, but that's why im on the forum... to ask for advice. I think this r1+r2 value is high... what would you expect to get on a 2 way lighting circuit?

 

[trev]

No where near 2 ohms mate but then again I wouldn't be happy with 145 on a rod system. In your position I'd be extending the EPZ.

 

[srl-8]

Trev, Are you say do away with the earth rod and use the swa for the earth? I will need to check if the armor is connected at the house end...

Although, you are not happy with 145 ohms, below 200 is considered stable as you know..?

 

[Plonker 3]

OP youmheed to measure the length of the circuit, then using the table in appB in GN3 work out,what your readings should be.

 

[Plonker 3]

You are measuring the R1+R2 from the DB in the garage arent you? And not from the DB in the house?

 

[SPARTYKUS]

export the earth?

If if someone could "Carlsberg" export the earth I'd go for that.

 

[uksparks]

The CSA of the armouring, I've got a table somewhere showing the CSA of each size SWA, I think a 2 core SWA has armouring equating to 16mm2

 

[telectrix]

Trev, Are you say do away with the earth rod and use the swa for the earth? I will need to check if the armor is connected at the house end...

Although, you are not happy with 145 ohms, below 200 is considered stable as you know..?

it bloody well better be. and with a proper gland. otherwise, i don't give you much hope for your assessment.

 

[trev]

Trev, Are you say do away with the earth rod and use the swa for the earth? I will need to check if the armor is connected at the house end...

Although, you are not happy with 145 ohms, below 200 is considered stable as you know..?

That's pretty much exactly what I'm saying mate, if the armour isn't connected then it's not that big a deal to put that right.