RCD's and large capacitive loads

[Graham Atkinson]

Hi all, just registered today and sorry to come straight in with a request for help.

I wasn't sure if this would be best in the commercial forum or the domestic one as really it is using comercial type equipment on a domestic ring main.

I have 2 large battery charger/inverters in use at my house which I can individually use with no issues but if i power both up together then at some point over the next 24 hours my RCD will trip. The chargers are a Victron Multiplus 12/2000/80 and a Mastervolt Mass Combi 12/4000/200. The inverters are not feeding in to the domestic supply so it is only the chargers that are effecting the RCD. I believe the problem will be due to the large capacitors built into these chargers causeing earth leakage which is beyond the normal level for a domestic (wylex type AC) RCD. I am just wondering if anyone has come up against a similar issue? Would the solution be to supply these inverters from a RCBO to remove the influence of all other electronics in the house or maybe run each charger from its own RCBO?

 

[LeeH]

It's a common problem, but not normally a domestic one.

Sharing the leakage between the 2 RCBOs is most probably the way to go without seeing the installation.

You could design a circuit to omit the RCD but probably pointless in your case.

One of the domestic chaps may offer a better solution.


EDIT: Also check its dropping out on earth leakage not overload. I haven't googled the charger specs.

 

[Graham Atkinson]

It definitely not overlaod. Max draw for both cargers together on full load is just over 20amps. They tend to trip the RCD after a few hours once the batteries are charge though so current draw will be minimal by that point. Its an 80a RCD and 32a MCB

 

[LeeH]

Measuring the leakage would be the best place to start, then a test on the RCD itself.

It may be letting go before its threshold.

Split the chargers across 2 circuits if you have a 2 way split RCD board.

RCD will be 30mA.