Gettings sparks when doing Ze, of Pfc

[Jel]

Hi,

Recently i tested to places, and when i carried out the above tests at one property i was getting a spark where the earth clamp joined the sheath off the main supply.
I also got it on a TNC-S system where it was sparking half way down the main SWA supply, and smoke was coming out of it each time?
What does this mean as i am very concerned?

 

[Spazz]

When was your meter last calibrated?

give the manufacture a call and ask them - they are the only ones who can give advice on this!

What make is it so others can be aware?

 

[Strima]

Poor connection on the sheath and damaged SWA at a guess. Did you isolate and check for damage, loose connections etc?

 

[Jel]

I could not Isolate, it was the supply from the Street coming into basement.
The first one did have very high Ze and i redid the clamp and got the reading down to a satisfactory level, however it did not eliminate the spark.
The metre is a megger mft1553, and it calibrated.

 

[Spazz]

have you had sparks on any other property? when doing a Ze test?

is your clamp clean?
is the cable clean? - not corroded

 

[Jel]

No has not sparked anywhere else.

The basement did smell damp, it was in a cafe, bags of rubbish and rat droppings, you can imagine the smell.

The other place was in a cupboard and the clamp did have a lot of grease around it?

 

[joe j]

Earth clamp?? That doesn't sound right to me