PIR query

bangtest · Sep 17, 2011

Hi,
doing a PIR on a property next week. Went yesterday to have a quick look for pricing.

This is the suppliers head. Not seen one like this before. The original TNCS earth is solid connection from the sheath to the side of the box - can be seen in the photo.
Someone has used a cable clamp to connect a more meaty earth.
So my question is - is this ok? Not done any testing as yet, even if Ze is ok, still seems as bit ropey.
Any advice/pointers on what exactly to report on this would be appreciated. Thanks in advance.

telectrix · Sep 17, 2011

it's TN-S, not TNC-S. the solid connection is the original DNO earthing.the problem, if any, with that BS951 clamp is that it could crush the supply cable. i'd make a comment on you PIR, not sure if it warrants a code. if you don't want to open the head, then you may have to enter a "lim" for the supply fuse characteristics. in any case, i would not disturb the earth clamp, subject to the Ze being below 0.8ohms.

bangtest · Sep 17, 2011

Yes, it is TNS. Dopey afternoon. Now thinking suggest to client to contact supplier and get head upgrade.

telectrix · Sep 17, 2011

worth a shot. if they will do it, get them to fit a 2 pole isolator as well.

WDMDL · Sep 25, 2011

Did a job for my old neighbours last year.... their new place had one of these, complete with matching isolator.

The arrangement seemed to have been altered from original, so that the isolator was on the consumer side of the meter.
I didn't open the head to check fuse type either.

Simon.