- Reaction score
- 3,010
Have been doing some small jobs on a commercial unit converted for storage, changing lights and broken sockets and the like.
Units look to be c.20 years old.
The interesting thing is the unit is Three Phase TT, the rod being directly beneath the DB and incomer all in a small cupboard.
There is a 30mA RCD on the tails to the board, no time delay.
The Zs at DB is 0.52Ohms
There are no apparent parallel paths, no gas on site, water plastic and I couldn't see any steel bonding.
It is a very curious set up that doesn't feel right.
Could the Earth Rod be attached to the steel foundations, hence the very low Zs for TT.
With such a low and consistent Ze is this RCD really necessary?
Anyone seen the likes of this, is it common?
Units look to be c.20 years old.
The interesting thing is the unit is Three Phase TT, the rod being directly beneath the DB and incomer all in a small cupboard.
There is a 30mA RCD on the tails to the board, no time delay.
The Zs at DB is 0.52Ohms
There are no apparent parallel paths, no gas on site, water plastic and I couldn't see any steel bonding.
It is a very curious set up that doesn't feel right.
Could the Earth Rod be attached to the steel foundations, hence the very low Zs for TT.
With such a low and consistent Ze is this RCD really necessary?
Anyone seen the likes of this, is it common?