Fitting a 100ma RCD on Solar PV to solve nuisance tripping.

[South Spark]

A solar PV system keeps tripping the 30ma B curve RCD (at dawn).

The system is a TNC-S and the cabling to the inverter is surface mounted SWA.

Is there any reason to not swap the 30ma main switch out for a 100ma ?

 

[Wilko]

Sorry to ask a dumb question - B curve RCD ?

 

[Dillb]

Does the cable require RCD protection?

 

[davesparks]

If the circuit requires 30mA RCD protection then no you cannot remove it.

 

[GeorgeCooke]

Find the fault, don't mask it.

If the oil pressure light comes on in your car would you remove the bulb?

 

[marconi]

Do you mean:
a. RCD/RCCB
b. MCB
or
c. RCBO

is tripping?

 

[Octopus]

I think he means the upfront RCD for all the circuits.

In this case no

 

[netblindpaul]

He probably means a B type RCD.
So it’s only tripping when the DC cables polarise at the start of generation?

 

[JD6400]

Hi South spark , what size system is it , make of inverters and is it domestic or commercial ?

 

[South Spark]

.

 

[South Spark]

Sorry to ask a dumb question - B curve RCD ?

B type sorry.

 

[South Spark]

Hi South spark , what size system is it , make of inverters and is it domestic or commercial ?

3.6 kw- domestic. Sunny Boy I think. Solar installation isn't mine. Isolated farm so a bit of a faff to be going to and fro.

 

[South Spark]

He probably means a B type RCD.
So it’s only tripping when the DC cables polarise at the start of generation?

Seems so from customer reports. He's been resetting the RCD and the system is working fine after that. Of course dawn is around 5.15 at the moment so he's missing out on a lot of FIT.

 

[Wilko]

Ha ha - he should get a cat, or an infant .

 

[marconi]

Would you know if the Sunny Boy is:

a. transformerless?
b. is disconnected from the SWA cable until PV generation starts?

One thing to look at (from netblindpaul#8) is how tightly have the dc cables been clamped around their insulation to any metalwork.

If there is more than one Sunny Boy (I expect so) can you disconnect one in turn and leave the others on-line to see if the problems goes away?