My highest ever Ze

[RF Lighting]

Went to put in a new cooker supply for a customer yesterday. Just doing a couple of quick checks before I got started and found the incomming supply to have a Ze of 11.40Ω on a TN-S

Good old cast iron cut outs

Anyway the nice chaps from northern powergrid came out and got the reading down to 0.31Ω

Aparrently the supply was looped off next door and both cables in their house and the cable in the one I was working in all had the earth clamps onto the cable armouring rather than the lead sheath.

I guess I'm the first person who's ever actually used a test kit in either of these houses then

 

[mfarrow]

What about the rest of the street?

 

[westie101]

Pah!
On our fault logs at the moment

AS PER ELEC CONS ON SITE. READINGS OF 99OHMS AT CONSUMER UNIT AND 0.14 AT I/C CABLE. STATES NOTHING TO CONNECT EARTH TO..

Our guy fitted a temp clamp and reduced it to 0.21. Cut-out change and permanant job being done later.

 

[securespark]

Double Pah!!

I've had 1936 Ohms on a TT supply, 1100-odd on a PME supply and 900-odd on TN-S.

See here:

//www.diynot.com/forums/viewtopic.php?p=608106#608106

The PME was in Staffs, can't remember exactly where but somewhere near the Brit, the TT was in Doveholes and TN-S escapes me but may have been Henbury.

The Doveholes was a Wylex board no RCD or VOELCB. THe old lady was told by her dearly departed to water the lawn but not why. When I traced the conductor, it was just stuck into the soil....

The Staffs job as the thread explains was just a loose link. The TN-S job was just like RF's but a more severe case of corrosion, both ferrous and cupric.

 

[sparkybird]

just yesterday went to look at a job had 46Ohms on TNS - shared supply (2 flats). Earth clamp' on supply waving around like a dogs leg and someone had disconnected the bonds off the water pipe as it had got in the way of the decoration....

 

[securespark]

Yeah, makes me smile when people do that.

Not...idiots.

 

[ebee]

One of my customers decided to saw the incoming PILC cable at floor level in her pantry because it looked untidy.
Seeing I was on site to fix one of her lights she decided to mention it to me first.
Phew!

 

[RF Lighting]

What must be going through peoples heads when they think that it would be a good idea to do stuff like that

 

[westie101]

I got called to assist the Fire Service at 07:00 this morning. Got there and found it had been a cut-out arching, sparking with a smell of burning. A fairly modern 100A unit that (from the thermal camera image) probably had weak contact springs.
The house has off-peak heating so it could have been a case of annealing from the constant higher loads.

Both CU's had been switched off so the removal of any load had stopped the problem. I had a discussion with the fire fighter about whether removing the main fuse would have been of benefit. After describing the risks and the PPE required we agreed that it would be an action of last resort.

By 10:30 the cut-out had been changed!

As for PPE, I was applying an LV backfeed to a substation last night (probably 150A per phase) so 1000V insulated gloves with leather protectors, full face protection, Nomex overalls and insulated tools.

 

[EFLImpudence]

What must be going through peoples heads when they think that it would be a good idea to do stuff like that

Not a lot.

What do people who can't think do when they're doing nothing?

 

[ban-all-sheds]

They post questions here with stories about their electrician being uncontactable because they are inside a Slaver stasis field.

 

[studentspark]

Impressed with the speed that the cutout was changed.

Was there a fused neutral, looks like work had been done there recently

Would be interested in some info on this Green and yellow "Tape" I have seen used recently. What CSA is it, how was it attached to the incoming cable

 

[westie101]

Would be interested in some info on this Green and yellow "Tape" I have seen used recently. What CSA is it, how was it attached to the incoming cable

I'll have a look on Monday, it's attached using a "Roll spring" or Constant Force Spring

http://www.etscc.co.uk/catalog/medi...nation-installation-accessories/raychem-mec-0

 

[RF Lighting]

It looked to me to be about 16mm². It was certainly bigger than 10mm²

 

[securespark]

It is meaty stuff. I can't remember how big (I have a sieve like a brain) but the ENWL guy I talked to about it recently said it is plenty big enough.

And the roll springs are great once installed correctly. Excellent continuity.

Had a dodgy clamp on a TN-S sheath once - ENWL came to it, tightened it up, got it down to 0.8 but was not happy with it so put a spring on it. Got the Ze down to 0.08....