Something like this is needed:
https://cpc.farnell.com/multicomp-pro/mp780050/mini-leakage-current-tester/dp/IN08364
Also you need to get the L and matching N in to the clamp to see the residual. I would strongly advise against moving cables in an energised DB! Try and get anything to measure in-place and accessible with all power off.
Ah nice find. The one I was looking at was ÂŁ5 more and not as accurate.
I am doing the L + N matching pair for the sockets and the DB. Both are accessible without moving the cables.
If it is type AC and tested on a type A waveform with DC component then it can be desensitised.
If 100mA rating it ought to trip between 50-100mA. You need to have all loads off so you are just testing it alone, and not having system currents also present.
I will test again on Wednesday when I am back at the unit. Or tomorrow night.
I am clamping the Live and Nutrual 4mm singles coming out of the RCBO. It ranged from 0.2A to 0.7A but it really came down to how I was holding the clamp meter on the cables and at what angle. That is why I don't believe my 20A clamp meter. Will wait for the one from CPC to arrive.Those are massive currents! Is that measured with L&N in the clamp, or are you (incorrectly) clamping the CPC? If so then any metalwork anything is in contact with could be causing odd currents to circulate.
Have you IR tested the power supply? I.e. the sort of basic PAT testing part (along with CPC bond resistance, etc)
Are you sure the power supply is going in to the RCBO's supply? There is something inconsistent with being able to trip the 100mA incomer and not trip the 30mA socket feed, unless the installation happens to be sitting only a few mA leackage below the trip point normally.
I tested N+E and L+E on that power supply up to 500v. No issues. Will look into the PAT procedure and get back to you on that.
There are only 3 circuits on the DB. Sockets, Door and Lights. I can follow the 4mm singles from the sockets up into the RCBO.
This is the reason why I am struggling to get my head around it all.