Positive Isolation

[SimonH2]

I recall being told a similar story where the electrician eventually got the message across with a length of thin wire between live and neutral in the switch box which created a small explosion when the switch was turned back on.

Or perhaps a very large bit of wire, so it takes out the upstream fuses and then the guy really gets it for shutting down part of the factory You could probably ague that if there's no lockoff facility then linking all the output terminals together and to earth would be the only way of ensuring your safety.

Someone else I know told me a story about when he was working on a supply in a tractor factory. They had this UPS which was 4off 1/4MVA units in parallel and the manufacturer claimed they could do pretty much anything to one module and the rest would keep going. While crouching down taking measurements, something went wrong. After picking himself up off the floor, he found what was left of his AVO smouldering away (one lead completely missing) - and everything had gone quiet. Apparently it took four days to get everything back up and running smoothly. I guess the system couldn't cope with whatever he shorted out

But that's getting a little off topic.

 

[onlyfitidealboilers]

hello again,

So am i right in saying the reason i can't use a multi meter for this test is because i may set it to Ω instead?

Incase the boiler case was live i would cause a short by putting my probe to earth?

I need a meter that only has a voltage setting for safety???

Cheers guys

 

[londonboy]

Have a look at the following:


http://www.test-meter.co.uk/product...-voltage-indicator-and-proving-unit-vipd-kit/

 

[holmslaw]

..