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Discuss Fitting a 100ma RCD on Solar PV to solve nuisance tripping. in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net

South Spark

Regular EF Member
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 ?
 

davesparks

Forum Mentor
Electrician's Arms
Trainee Access
If the circuit requires 30mA RCD protection then no you cannot remove it.
 

marconi

Respected Member
Forum Mentor
Electrician's Arms
Trainee Access
DIY
Do you mean:
a. RCD/RCCB
b. MCB
or
c. RCBO

is tripping?
 

Murdoch

Electrician's Arms
I think he means the upfront RCD for all the circuits.

In this case no✋
 

netblindpaul

Forum Mentor
Electrician's Arms
CCTV / Alarms
Trainee Access
He probably means a B type RCD.
So it’s only tripping when the DC cables polarise at the start of generation?
 

JD6400

Forum Mentor
Electrician's Arms
CCTV / Alarms
Solar Guru
Trainee Access
Hi South spark , what size system is it , make of inverters and is it domestic or commercial ?
 

South Spark

Regular EF Member
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.
 

marconi

Respected Member
Forum Mentor
Electrician's Arms
Trainee Access
DIY
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?
 

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