The dangers of testing

[La Poste]

Howdy folks.

This one is for the 2391 exam.

I was wondering if you were asked the following question:
"what are the dangers of testing an installation with members of the public being present?"
What would be your answer?

I would say earth fault loop impedance and RCD testing could raise the earth circuit including all exposed conductive parts to line potential in the worse case scenario IE having a high resistance earth fault loop path.
This could result in any exposed metal work connected to earth being raised to 230V including metal light switches, socket faces etc or am I wrong?

Also insulation resistance testing at 500V although I am not sure how dangerous this would be.
I mean does an insulation resistance test between line and earth raise the earthed metal work to 500V?
There is still a lot I am not sure about with testing an installation.

Of course we have safe isolation and all that stuff but if we had carried out safe isolation and placed warning signs etc what would the dangers of testing an installation be?

Any comments welcome.

Thanks.

 

[IQ Electrical]

Howdy folks.

This one is for the 2391 exam.

I was wondering if you were asked the following question:
"what are the dangers of testing an installation with members of the public being present?"
What would be your answer?

I would say earth fault loop impedance and RCD testing could raise the earth circuit including all exposed conductive parts to line potential in the worse case scenario IE having a high resistance earth fault loop path.
This could result in any exposed metal work connected to earth being raised to 230V including metal light switches, socket faces etc or am I wrong?

Also insulation resistance testing at 500V although I am not sure how dangerous this would be.
I mean does an insulation resistance test between line and earth raise the earthed metal work to 500V?
There is still a lot I am not sure about with testing an installation.

Of course we have safe isolation and all that stuff but if we had carried out safe isolation and placed warning signs etc what would the dangers of testing an installation be?

Any comments welcome.

Thanks.

That's why you should NEVER carry out EFLI or RCD tests before verifying continuity of main protective bonding etc.

I wouldn't carry out IR tests in an occupied building, you just never know where that test voltage ends up!