EICR remedial

yellowvanman · May 6, 2015

Just done an EICR on an outbuilding that is habitable (kitchen/wetroom etc). Supply is taken from henly block in the meter cupboard, via 2 core SWA to building. At building SWA is glanded into a metal box but the box (earth) is not connected to the plastic consumer unit which sits right next to the metal box. Ze for the outbuilding rod is 350ohms.

So I've got 2 problems, 2 earths (house PME) and outbuilding (TT) in close proximity and the TT giving a poor reading.

Water supply to outbuilding is in plastic pipe and in the outbuilding the connected copper pipework is bonded.

Whats stopping me using the SWA to provide the PME earth to the outbuilding, to fix both problems? I know the water pipes are bonded but they are not extraneous, although I haven't done the test to confirm.

telectrix · May 6, 2015

Whats stopping me using the SWA to provide the PME earth to the outbuilding, to fix both problems? I know the water pipes are bonded but they are not extraneous, although I haven't done the test to confirm.

as long as there's no extraneous in the outbuilding. if there is after you've tested (if <22kOhms, then you'd need a 10mm bonding conductor from the house MET. alternative would be to improve the Ra of the TT system and ensure the outbuilding installation is RCD protected.

sinewove · May 6, 2015

Why not either knock more rods in 2 reduce reading to less than 200 ohms,or pme the building if as you say the pipework is not extraneous.
Regards sw

bigspark17 · May 6, 2015

Why didn't you test from MET to pipe work? >22k ohms then not extraneous! But surely would be better to improve Ra , what electrode is in place sounds like a 3/8? Is there an up front RCD,?

yellowvanman · May 6, 2015

bigspark17 said:
Why didn't you test from MET to pipe work? >22k ohms then not extraneous! But surely would be better to improve Ra , what electrode is in place sounds like a 3/8? Is there an up front RCD,?

As in my first post wanted to try and kill 2 birds with one stone, re mixture of earthing in one location. Existing electrode is the thin one that you can't extent. 10 years ago Ze was about 150, also its on a side of a hill and I suspect will need a few rods knocked in to get a decent reading, so looking for an easier solution.

CU has 100mA time delayed RCD up front with 30mA for sockets.