How to bypass an RCD and carry out an insulation resistance test on a circuit

TonyTheTiger · Sep 6, 2018

Hi all.

[ElectriciansForums.net] How to bypass an RCD and carry out an insulation resistance test on a circuit

I'm a 4th year electrician currently awaiting to finish my trade test. (FICA in Scotland) the only parts I have to pass is the testing part and fault finding.

I'm currently studying testing as this is something I have done the minimum of onsite.

Could someone tell me how I would bypass the rcd when carrying out an insulation resistance test as I don't want to damage the RCD. I will attach a picture of board I am testing

Thanks in advance

Pete999 · Sep 6, 2018

TonyTheTiger said:
Hi all. View attachment 44150

I'm a 4th year electrician currently awaiting to finish my trade test. (FICA in Scotland) the only parts I have to pass is the testing part and fault finding.

I'm currently studying testing as this is something I have done the minimum of onsite.

Could someone tell me how I would bypass the rcd when carrying out an insulation resistance test as I don't want to damage the RCD. I will attach a picture of board I am testing

Thanks in advance

Safe Isolation, and test from the load side with the cables disconnected. Or can you swap the RCD temporarily with an Isolator to do your testing?

JOURNEYMAN · Sep 6, 2018

As Pete999 said. Isolate and test from load side with cables disconnected.

TonyTheTiger · Sep 6, 2018

Hi Pete. Good to hear from you again aswel sir! You may not remember but you helped me with some feedback a while ago aswel. I really appreciate it mate & also a big thanks to you journeyman for taking the time to help me. Im truly grateful.

I cannot swap the RCD for an isolater unfortunately. I am just having a look at my On site guide right now before I go back to the board. I will keep you both posted.

Thanks once again, sincerely!

Pete999 · Sep 6, 2018

TonyTheTiger said:
Hi Pete. Good to hear from you again aswel sir! You may not remember but you helped me with some feedback a while ago aswel. I really appreciate it mate & also a big thanks to you journeyman for taking the time to help me. Im truly grateful.

I cannot swap the RCD for an isolater unfortunately. I am just having a look at my On site guide right now before I go back to the board. I will keep you both posted.

Thanks once again, sincerely!

No worries mate, glad to help.

telectrix · Sep 6, 2018

if that board is your install, you need a kick up the arse. bare copper exposed on the L incomer to the main switch.

MDJ · Sep 6, 2018

telectrix said:
if that board is your install, you need a kick up the arse. bare copper exposed on the L incomer to the main switch.

Yup, however the board is a bit tatty, he will get there in the end though, still 4 years in, should be better.

Deleted member 26818 · Sep 6, 2018

Would have

telectrix said:
if that board is your install, you need a kick up the arse. bare copper exposed on the L incomer to the main switch.

Look at the second RCD.

TonyTheTiger · Sep 6, 2018

Not my Install lads. It's the consumer unit of my Girlfriend's house. She lives in a council house so it must have been the local council who installed the board. Ive worked predominantly on domestic new builds so fitting out Consumer units is one of my better skills. I agree the copper exposed on the terminations leaves a lot to be desired. I'll fix it as I go along. Thanks again everybody regardless if it's advice or criticism, I appreciate all the feedback .

KEV 1 N · Sep 6, 2018

telectrix said:
if that board is your install, you need a kick up the arse. bare copper exposed on the L incomer to the main switch.

As well the bare copper, the strands appear to have been damaged when stripped.
The cross sectional area is compromised here....

KEV 1 N · Sep 6, 2018

Just noticed this as well....oh dear!

telectrix · Sep 6, 2018

KEV 1 N said:
Just noticed this as well....oh dear!
View attachment 44157

that 25mm looks as if it's been stripped by a beaver. i always cut the outer sheath back 1/4" so you can see the brown/blue ibsulation layer. then you know if you'f put it in the wrong hole.