Regs on a high Zs
- Thread starter Booyaka
- Start date
Sponsored Links
Because you can't export an earth to an outbuilding on a PME supply hence he's converted to a TT earthing system.
The earthed armouring is protection for the cable run only.
That's how I've read it anyway.
So the short amount of cable between the earthing conductor for the TT electrode and the point of utilisation amounts to 3 ohms? Might be me but that seems a bit on the high side.
Why haven't you exported the PME?
Why can't you export a PME earth to an outbuilding? Earth armouring, as long as it complies with the adiabatic equation or 54G (taking into account the material) and if it is to be used as a main equipotential bonding conductor it also complies with 54H and the DNO requirements it is fine.
Sponsored Links
as written in an earlier reply one of you guys gave my a link to a pdf explaining all
yes you can export the PME if there are no extraneous parts in the outbuilding however if there is then thew SWA is earthed from the PME for the cable only then stops at the outbuilding where electrode is installed and equipotential bonding is applied from there which is what ive done
what the queory originally was....
i am lead to believe that on my TT system if the Zs of a circuit does not comply with the regs then protecting it with an RCD will then comply with regs and yes all circuits in outbuilding are RCD anyway
yes you can export the PME if there are no extraneous parts in the outbuilding however if there is then thew SWA is earthed from the PME for the cable only then stops at the outbuilding where electrode is installed and equipotential bonding is applied from there which is what ive done
what the queory originally was....
i am lead to believe that on my TT system if the Zs of a circuit does not comply with the regs then protecting it with an RCD will then comply with regs and yes all circuits in outbuilding are RCD anyway
Which regulation does a TT supply with a Ze of 5 ohms not meet? Are you looking at information for TN systems?
Though as I have said on a few occasions, to gain 3 ohms within a short space would, to me, indicate a problem.
Though as I have said on a few occasions, to gain 3 ohms within a short space would, to me, indicate a problem.
http://www2.theiet.org/Publish/Wire...matters_electrical_installations_outdoors.pdf
Here you go
it was on another i spoke about
Here you go
it was on another i spoke about
no its the high Zs i was worried about,
Ze TT 5ohm, Zs radial socket on 16A 8 ohm, so its RCD'd
I wouldn't normally be worried with a Zs of 8 ohms on a TT as protection against indirect contact is by RCD. However as you have said the Ze is 5 ohms and a not too far away a Zs reading is 8 ohms then it would make me double check nothing is amiss.
This thread seems to go on and on with no definite solution
Booyaka - what is the Ze at supply at house?
Why isn't the outer steel of SWA terminated properly at out building this would reduce the Z value at out building.
You need to investigate why you have 3 ohms on radial cct within outbuilding - this value is far to high.
Have you measured R1+R2 at out building.
Have you read and understood the IEE wiring matters article?
Booyaka - what is the Ze at supply at house?
Why isn't the outer steel of SWA terminated properly at out building this would reduce the Z value at out building.
You need to investigate why you have 3 ohms on radial cct within outbuilding - this value is far to high.
Have you measured R1+R2 at out building.
Have you read and understood the IEE wiring matters article?
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
Sponsored Links
