Could someone explain?

[longdogs]

I went to fit an immersion heater timer for a customer the other day. Affter removing the fused spur, I checked the live wire with a tester screwdriver (I normally do this to check that the bulb is working before switching the supply off). There was no power at all. I then tested a couple of sockets which were fine (screwdriver lit up) and then I tried testing the circuits at the consumer unit and found that no matter what the tester touched it did not light up, not even the main live cable into the house. Is it normal for a tester screwdriver not to light up when touching the supply cable? or is there a hidden problem somewhere?

Jobs finished now but just wanted to know for future reference. Thanks

 

[oharaf]

throw it in the bin!!!!!

 

[rebuke]

As has been said - those tester screwdrivers are crap, they give false positives due to static, and false negatives due to a bad ground / the shoes you're wearing etc...

Also, the only thing between you and the voltage is a small resistor, if for some reason that breaks in such a way that it short circuits, you'll get a nasty shock.

Slightly better than a tester screwdriver is what's known as a volt stick, these light up (and normally beep) if a voltage is present, and use a battery so aren't relying on you for a ground, but the ideal thing to use is a GS38 approved voltage tester such as http://www.tlc-direct.co.uk/Products/TMDL6780.html (other suppliers etc are available)...

 

[ban-all-sheds]

Plus there's the minor matter of GS38 and EAWR #10, 14 & 16...

 

[rebuke]

Ah, I hadn't noticed the "for a customer" bit in the OP - as BAS says, if you're doing it professionally and not following an approved isolation process then you're in breach of various regulations...

 

[oharaf]

you clealry don't know what you're doing and do not have the appropriate equipment, I some how doubt you have the neccessary qualifications.

Stop what you are doing and advise the customer to find an electrician

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