PFC Test Industrial RCD

[Pmarsh]

Hi all, most of my work is industrial, I'm required to test a consumer unit in a hydro generation unit.
This is not an issue I'm just struggling with the PSCC Live test as there is an industrial RCD directly after the incoming supply from Scottish power due to us having to supply our own earth TT. I've managed a PEFC test on the board on the no trip setting of my megger MFT1552 and have Very low reading understandably due to the TT earthing arrangement.

Every time I try a PSCC test it trips the industrial RCD. Is there a way around this using my tester or will bypassing the RCD be the only option. I would like to do the test at the board as there's a 40meter 50mm supply cable running back to the supply metering room that I would like to take into account.

As I say most of my work is industrial, so not overly familiar with the tester.

Any help would be appreciated

Thanks

 

[Bobster]

Will your tester measure phase to phase? This shouldn't bother the RCD unit.

Rule of thumb would be to just double the PEFC but as it's TT and you're measuring low current it will likely be lower than it potentially could be.

 

[Ian1981]

Measure phase to phase as rob said.
I've got a megger mft 1552 and it's good for 500v so no bother there.
You could measure phase to neutral and double your reading as a rule of thumb but your pfc will always be the measured value between phases and if single phase on a TT phase to neutral.

 

[Pete999]

Hi all, most of my work is industrial, I'm required to test a consumer unit in a hydro generation unit.
This is not an issue I'm just struggling with the PSCC Live test as there is an industrial RCD directly after the incoming supply from Scottish power due to us having to supply our own earth TT. I've managed a PEFC test on the board on the no trip setting of my megger MFT1552 and have Very low reading understandably due to the TT earthing arrangement.

Every time I try a PSCC test it trips the industrial RCD. Is there a way around this using my tester or will bypassing the RCD be the only option. I would like to do the test at the board as there's a 40meter 50mm supply cable running back to the supply metering room that I would like to take into account.

As I say most of my work is industrial, so not overly familiar with the tester.

Any help would be appreciated

Thanks

What is an industrial RCD??

 

[Bobster]

What is an industrial RCD??

I'm presuming some form of earth leakage detection connected or built into an MCCB. You're right though, no such thing as an industrial RCD.

 

[Pmarsh]

Yeah I've self named it as it's large takes 50mm cables and is used for the industrial work I'm doing.. imaginative I know , basically it's just a large 3 phase Schneider earth leakage MCCB as you stated rob. Ok will give phase to phase a go, thanks all.

 

[westward10]

Make sure your tester won't implode across lines first!!

 

[Leesparkykent]

The PSCC will diminish with impedance so if the value is within limits at the origin then no need to carry the test out at the board is there?

 

[davesparks]

How are you carrying out the PSCC test at the moment? It seems very odd that it should trip an earth leakage relay, have you tried adjusting the settings of the relay temporarily to allow the test to be carried out?

 

[Pmarsh]

Line and neutral supply side of RCD at board pfc setting on tester