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?

 

[davesparks]

It does feel like I'm doing more than I should if you know what I mean, think about it, why am I bothered about the installation and esrthing that when that's already got a perfectly good earth.

I I feel if I put a charger in, with an additional rod, I've done my bit, then in the event of a fault where you loose the neutral, it's there as a fail safe / backup.

You are bothered about the installation because you are trying to comply with that (ii) option for connecting to the PME earth.

If you don't want to do that then obviously you can just not connect it to the PME earth and set up you own earth system just for the charging point, but you will then have to make sure that all metalwork connected to it is suitably far away from any bonded to the PME earth and also that the electrode's zones of influence don't overlap with those created by any buried steelwork bonded to the PME earth.

 

[uksparks]

Yes so the plan is to bang a stake in, get a Good reading and connect it to the end of the circuit.

 

[spark 68]

I can see your point with this, but what are the chances that the building is going to be so far out of balance that the neutral current is going to be that great?

Maybe not at the moment it isn't, but I seem recall Tony of this parish had overheating Bonding conductors, and I don't fully trust BS951 clamps, or plumbers replacing them either properly or at all ;-) plus if you are going to all this bother in the first place why not ? it would not cost that much more in the scheme of things now that we are trying to achieve sub ohm TT rod nests, just my opinion of course

 

[Guest125]

I like the way this thread has conducted itself.

 

[uksparks]

It's actually been quite constructive with no abuse!

 

[Guest125]

Agreed.

 

[TJ Anderson]

I seem recall Tony of this parish had overheating Bonding conductors

Turned out he had clipped them outside on a south facing wall in mid July.

 

[Guest125]

School boy!

 

[uksparks]

I could take a 10mm back to the met, it's about 16 meters so not going to cost the earth, just strap it to the side of the swa.

I suppose when it gets outside, I'll just tie it to the tray, but it's not exactly uv resistant is it not should be outside unprotected like that, so that then creates yet mother sodding problem.

 

[spark 68]

Yeah I looked at that in Amd 2 Archy,
My only niggle with that is if it can be guaranteed , plus I as trying to be constructive with all of the methods available

To throw another grenade a 1:1 isolation transformer is yet another available method

Good discussion a lot better than " my RCD is tripping help!" threads

 

[Leesparkykent]

I could take a 10mm back to the met, it's about 16 meters so not going to cost the earth, just strap it to the side of the swa.

I suppose when it gets outside, I'll just tie it to the tray, but it's not exactly uv resistant is it not should be outside unprotected like that, so that then creates yet mother sodding problem.

stick it in copex

 

[spark 68]

I could take a 10mm back to the met, it's about 16 meters so not going to cost the earth, just strap it to the side of the swa.

I suppose when it gets outside, I'll just tie it to the tray, but it's not exactly uv resistant is it not should be outside unprotected like that, so that then creates yet mother sodding problem.

16mm can be buried direct

 

[Guest125]

Yeah I looked at that in Amd 2 Archy,
My only niggle with that is if it can be guaranteed , plus I as trying to be constructive with all of the methods available

To throw another grenade a 1:1 isolation transformer is yet another available method

Good discussion a lot better than " my RCD is tripping help!" threads

i think because it is not in everyone's everyday workload list everyone is listening to everyone else. Very good thread.

 

[uksparks]

Yeah I looked at that in Amd 2 Archy,
My only niggle with that is if it can be guaranteed , plus I as trying to be constructive with all of the methods available

To throw another grenade a 1:1 isolation transformer is yet another available method

Good discussion a lot better than " my RCD is tripping help!" threads

The transformer idea could be an idea, but I think I'll stay away from that one as I've already agreed a price and don't want to go too far astray, I'm still well in acceptable.

Yeah it's a good thread, it's nice that it's not been ripped apart, I thnk we have all have valid points and probably all had differing views.

 

[uksparks]

16mm can be buried direct

Hmm, I'll weigh up the costs.