Testing question

[m top]

hi all I am currently working as a mate the contractor I'm working for which I shall not name does the following test.
he only measures zs doesn't do continuity r1 r2 he says that there is a good earth return if these results are within those permitted, he takes his ze from his zs to obtain his r1 r2 value,,now I am not saying I am right but shouldn't you prove a earth path exist before you power up to comply with ados ? The only reason I can see he does this is to save time but I'm guessing he is cutting corners views please or is this permitted.

 

[Regs]

The initial verification would be to the equipment you have installed.....ie the CU and associated gear,such as the RCD's......not the existing outgoing circuits.
IMO essential tests on existing unaltered final circuits would not include R1+R2. IR tests and Zs would be essential because of the changed characteristics of the new protective devices.
R1+R2 tests would be advised but not essential and could be noted as a limitation on the EIC if not carried out.

Thank you, perfect answer.
I was not asking to get out of doing an R1+R2 as i was previously accused, anyway:

You say changed characteristics i get the Zs part as you could be going from bs3036 rewireable to 60898's so different Zs's. Where does the IR come in please?

If you don't do R1+R2 then how would you confirm polarity? When polarity is mentioned is it just reverse Neutral and live being referd to or any cables incorrectly wired?

 

[telectrix]

polarity faults can be a L-N reversal or a N-E reversal. if the latter, everything works fine till you fit a RCD.

 

[Regs]

polarity faults can be a L-N reversal or a N-E reversal. if the latter, everything works fine till you fit a RCD.

You have not mentioned L-E also, but then reading above i assume you mean everything.

 

[jeffelectric]

i have been working for a firm a month now , they haven't tested any circuits before commissioning , didn't even test an earth rod, i guess 20 years of experience lets them know testing is a waste of time.

 

[Regs]

hi all I am currently working as a mate the contractor I'm working for which I shall not name does the following test.
he only measures zs doesn't do continuity r1 r2 he says that there is a good earth return if these results are within those permitted, he takes his ze from his zs to obtain his r1 r2 value,,now I am not saying I am right but shouldn't you prove a earth path exist before you power up to comply with ados ? The only reason I can see he does this is to save time but I'm guessing he is cutting corners views please or is this permitted.

Look at it this way, when you pass your driving test you get taught to drive at 30 MPH on back streets, in reality how often does this happen? testing is the same. Thats not to say i'm encouraging cutting corners!

 

[Regs]

The initial verification would be to the equipment you have installed.....ie the CU and associated gear,such as the RCD's......not the existing outgoing circuits.
IMO essential tests on existing unaltered final circuits would not include R1+R2. IR tests and Zs would be essential because of the changed characteristics of the new protective devices.
R1+R2 tests would be advised but not essential and could be noted as a limitation on the EIC if not carried out.

Can anyone please tell me:

You say changed characteristics i get the Zs part as you could be going from bs3036 rewireable to 60898's so different Zs's. Where does the IR come in please?

If you don't do R1+R2 then how would you confirm polarity?