When testing a circuit protected by RCBO, do you test at the DB or furtherst point

[littlespark]

Can I just interject into this discussion.

My rcd tester comes with 2 leads. One with 3 prongs and croc clips, the other with a regular square pin plug(top)

If we were only to test the device, there would be no need to supply the lead with the plug on.


I see it as one of the reasons we have rcd’s is to protect users when you plug in a faulty appliance, so the outlet itself should be tested.

 

[magnoliafan89]

Surely its whichever is more convenient at the time of testing surely?? Why are people so aggressive about this? If you're already in the board just check it at the device...if not just plug it in. Stop being girls about this....

 

[Deleted member 26818]

Surely its whichever is more convenient at the time of testing surely?? Why are people so aggressive about this? If you're already in the board just check it at the device...if not just plug it in. Stop being girls about this....

It’s all about why you are testing the RCD/RCBO.
If you are testing it just to see whether it works, then yes test at the most convenient point.
If you are testing to prove it provides additional protection, then test it at the point where the additional protection is required.

Not aware anyone is getting aggressive about it.

 

[magnoliafan89]

It’s all about why you are testing the RCD/RCBO.
If you are testing it just to see whether it works, then yes test at the most convenient point.
If you are testing to prove it provides additional protection, then test it at the point where the additional protection is required.

Not aware anyone is getting aggressive about it.

I personally dont see any need to test at the point. If it works at the board...its going to work in general.

 

[Deleted member 26818]

I personally dont see any need to test at the point. If it works at the board...its going to work in general.

So, if you were to test at the board and the RCD passed, then test at a socket and the RCD failed, you’d be happy?

 

[Midwest]

That IET article is from 2014.

Nothing’s changed then.

 

[telectrix]

don't blame me. i didn't put them there. and it wasn't my fault the Titanic sank.

but i think Pirate had something to do with it. all that gold jewellery on the women passengers. yo ho ho.

 

[The Ghost]

I think H&S and supporting statutes have something to say on this. Strictly speaking getting up a ladder to test lights is a no no in some commercial places I have been in. And opening a CU is working on something live which we should not be doing if there is a safer way to work i.e. at a socket or light switch. Therefore not at the CU with cover off then?

 

[telectrix]

suppose you test the RCD at CU with circuits dissed. it passes with good readings. installation is then re-energised, cert. supplied, next job. however 1 circuit has a nasty N-E fault which inhibits the RCD from working. customer is electrocuted. if test was carried out at a socket, the problem would have been seen and rectified. so I'm with spin on this issue.

 

[Pete999]

suppose you test the RCD at CU with circuits dissed. it passes with good readings. installation is then re-energised, cert. supplied, next job. however 1 circuit has a nasty N-E fault which inhibits the RCD from working. customer is electrocuted. if test was carried out at a socket, the problem would have been seen and rectified. so I'm with spin on this issue.

I'm with Spin and Tel

 

[Risteard]

It’s all about why you are testing the RCD/RCBO.
If you are testing it just to see whether it works, then yes test at the most convenient point.
If you are testing to prove it provides additional protection, then test it at the point where the additional protection is required.

Not aware anyone is getting aggressive about it.

Incorrect premise.

 

[Midwest]

I’m with Spin, Tel, Pete, and me.

 

[Risteard]

suppose you test the RCD at CU with circuits dissed. it passes with good readings. installation is then re-energised, cert. supplied, next job. however 1 circuit has a nasty N-E fault which inhibits the RCD from working. customer is electrocuted. if test was carried out at a socket, the problem would have been seen and rectified. so I'm with spin on this issue.

Your insulation tests would have discovered this.

 

[telectrix]

Your insulation tests would have discovered this.

you'd think so, but IR testing with modern digital testers can be hit and miss. had several cases of trapped L conductors showing >299Meg. on test but tripping MCB when energised. also had a couple of N-E fault stopping RCDs working . tested fine, >200Meg. .as a last resort on one of the latter, i used old wind up megger. that showed 15K ohms. think it's the fact that the old wind up jobbies can push out higher current. . moral here is don't mock the oldies. (you listening pete? old school beats the new tech.... hands down).

 

[ELECNEWT]

I think H&S and supporting statutes have something to say on this. Strictly speaking getting up a ladder to test lights is a no no in some commercial places I have been in. And opening a CU is working on something live which we should not be doing if there is a safer way to work i.e. at a socket or light switch. Therefore not at the CU with cover off then?

I'm with Vortigern on this.
I think this should be the definitive answer.