Modern wiring help rcd trip

[RutlandFox]

Hi all. Newbie please be gentle...

My daughter in law moved into a new [2007] build. All socket circuits 20A radial MCB. One socket circuit trips rcd intermittently when the Wi-Fi router psu plugged in. Psu is double insulated and pat tests ok. Radial tests out ok with 50M ohm at 500v. Nothing obvious in the socket backs. Any ideas what to look at next? I'm here for the day visiting. Thanks!

 

[BruvDunk]

Yup, agree with the above.
Prob best not to alter anything if it doesn't look standard.. just have a moan to the landlord and get them to sort it.
Could be a can of worms

 

[davesparks]

That looks like some kind of pre fabricated wiring system, there may well be a central connection point for each circuit.

 

[Lucien Nunes]

Psu is double insulated and pat tests ok.

Did you test it yourself, i.e is the test trustworthy? I mention this because if it was someone else's test, I would double check it. A lot of numpty testers don't seem to connect the earth probe to the DC output connector when they 'test' small power supplies, so in fact they are not testing anything. It could have any amount of leakage or insulation failure from line to output but they wouldn't find it.

Actually, what happens if you power-up the PSU but don't connect the DC output to the actual router? Keep the plug out of contact with anything, so that there cannot be any earth leakage because the only connections are to L & N. If the RCD now doesn't trip, that suggests it is a leakage problem. If it trips, then you have something spooky going on.

 

[DefyG]

Had a similar problem on a job myself recently and it may just be a coincidence that the RCD trips when the router is plugged in as the neutrals are common.
24mA is not too low for a 30mA RCD. You don't mention the 'half times' test, may indicate a faulty RCD.
Also no IR test results - Possible cable fault!
If the circuit tests satisfactorily, its possible the accumulated leakage current from all the RCD protected circuits exceeds 24mA.

 

[Markyd]

So you whacked in a new rcd...which means you are now responsible for that circuit....or all the circuits on the rcd side....hope you have filled out an EIC or if anything goes wrong in that property you will be liable...not the landlord

 

[dmxtothemax]

have you tried a differant PSU on the router ?

 

[Pete999]

In the socket picture, what do you call the connector? I haven't seen that before.

Looks like a DIY extra socket to me