Cable size

[uksparks]

Hi,

I am going to be connecting an out door power supply, away from the building, its all metal casing.

The supply is 10mm, I am using a 3 core SWA for part of the run, the inside part was going to be in twin and earth, but then I was just thinking, going on table 54.8 section 544.1, am I looking into this too much or does it need to have a 10mm earth as its extraneous metal which is fixed into the ground?

In which case I was just thinking of running 3x 10mm inside the building so the earth is 10mm too to them comply with min size of bonding conductor.

I am right to make it 10mm throughout the entire run aren't i?

 

[shanky887614]

Where did you get your BYB from? I was just looking on Amazon and they are out of stock.

I have not got the BYB yet, but have a copy of AMD3.

Looking at (ii), I did read somewhere that the resistance must be very low, something like less than 3 ohms maybe, does anyone have any clarification of this?

hmm let me think.

maybe i preordered it months ago

 

[uksparks]

Yep. If you are planning to work for this customer again I would recommend installing to the 3rd. You don't want some idiot slagging you off in 7 months time saying "he gave you an out of date installation mate". Even though he would be wrong.

You have got a valid point.

 

[uksparks]

hmm let me think.

maybe i preordered it months ago

ah i see!

 

[shanky887614]

ah i see!

im usually organized

 

[Guest125]

I have got to dig a 2ft deep hole anyway for the mounting plate to be sat in, so can just dig across a little bit and see whats there, unlikely theres anything where this is going though.

What do you think? 2 rods maybe? Its next to a marina too, so the ground might be quite wet (if it leaks)

Famous last words mate. Don't risk it. Especially if 2 rods are required. We install 1 rod at a time then test. No point going further than required.

 

[uksparks]

Famous last words mate. Don't risk it. Especially if 2 rods are required. We install 1 rod at a time then test. No point going further than required.

I have no means to scan the ground unfortunately, can you rent them?

 

[spark 68]

Just a thought if he does TT it, it is close to a metal clad building which is itself TNCS/PME and also likely to be bonded via the structural steelwork , your are not supposed to be able to touch two different earthing systems simultaneously, this can itself be a shock hazard due to the differences between true earth (TT) and the PME earth.

I don't know the reg number off the top of my head, and it may be a DNO rule, I would have to look it up to back this statement up.

 

[davesparks]

Yep. If you are planning to work for this customer again I would recommend installing to the 3rd. You don't want some idiot slagging you off in 7 months time saying "he gave you an out of date installation mate". Even though he would be wrong.

He's got more worries than just that if he's installing less than 20mtrs of new SWA with a plastic joint box in the middle of it, not bonding a lump of metal that the charging point is fixed to and connecting it all to a PME supply.

 

[uksparks]

He's got more worries than just that if he's installing less than 20mtrs of new SWA with a plastic joint box in the middle of it, not bonding a lump of metal that the charging point is fixed to and connecting it all to a PME supply.

Im going continuous now actually, you are not up to speed LOL.

 

[uksparks]

Just a thought if he does TT it, it is close to a metal clad building which is itself TNCS/PME and also likely to be bonded via the structural steelwork , your are not supposed to be able to touch two different earthing systems simultaneously, this can itself be a shock hazard due to the differences between true earth (TT) and the PME earth.

I don't know the reg number off the top of my head, and it may be a DNO rule, I would have to look it up to back this statement up.

This was my other part of the jigsaw, its too close, and I know its bonded as have seen it all inside against the back of the skins.

Hmm its not very straight forward is it.

I say just connect to the PME system, its too close.

 

[driverman]

Not read all the threads, but SWA going though 2" wall shouldn't be a mess. Drill though wall at a steep angel ie 60 degrees.

 

[Guest125]

I have no means to scan the ground unfortunately, can you rent them?

Yes mate. Please do.

 

[uksparks]

Yes mate. Please do.

What is it I'm looking for? A cable scanner? Utility avoidance scanner?

 

[Guest125]

Just a thought if he does TT it, it is close to a metal clad building which is itself TNCS/PME and also likely to be bonded via the structural steelwork , your are not supposed to be able to touch two different earthing systems simultaneously, this can itself be a shock hazard due to the differences between true earth (TT) and the PME earth.

I don't know the reg number off the top of my head, and it may be a DNO rule, I would have to look it up to back this statement up.

it is a minefield eh?

It it is unusual for DNOs to provide earths to metal framed building is it not?

This is job may need a step back and reasses. Many heads are better than one.

 

[Guest125]

I really cannot spell on this forum.