Solar system tripping out mains.

[lennyg]

I cannot see your inverter (5500) on the mastervolt site:
Solar Inverters 1-10 kWp | Mastervolt Solar energy solutions
Which one is it?

Yes, that was a strange one, I was never able to find it on their site, however, when I plug in masterlog software, it reports it as XS6500 Though all the paperwork refers to 5500

 

[Earthstore]

Just a thought on the cable that was used, it is possible that it will have a high voltage drop, which is making your system go overvoltage, and tripping the RCD which sounds like it is wired up wrong anyway.

 

[lennyg]

Does your current comsumer unit have two RCD units? Or just the one?

If it is just the one, and the method of installation allows it, the installer could simply move the circuit to the other side of the board - looking at your picture, there appears to be a spare way.

The unit has 1 RCD..

 

[lennyg]

Just a thought on the cable that was used, it is possible that it will have a high voltage drop, which is making your system go overvoltage, and tripping the RCD which sounds like it is wired up wrong anyway.

The cable from the inverter (in the loft) down to the export meter in the photo, or the cable from the meter into the consumer unit?

 

[SolarCity]

The unit has 1 RCD.. View attachment 11415

Ask your installer if it is possible to move the circuit to the non-RCD protected side of the board. It may be the case that the way he has wired the installation means that it requires RCD protection - if not, then this is a very simple solution.

 

[BruceB]

6500 it is then.
As others have said, the problem is that it is sharing the rcd.
I could not see anything specific in terms of recommendations for rcds in the instructions, but it is galvanically isolated and should be able to take being on a standard 30mA rcd.
Opinions differ a bit, but normally I would not use an rcd for an inverter unless there was a specific reason to do so. Some installers are in the rcd everything brigade.
You probably have small leakage currents in your existing circuits on the rcd, either from the cables or from an appliance. That by itself is not enough to trip the rcd. Nor is the solar pv on its own enough to trip the rcd. However when the leakages are combined they do trip. A 30mA rcd is within spec provided it trips above 15mA and by 30mA (in simple terms).

The answer as others have indicated will be to separate the circuits so the solar pv is not sharing an rcd with others.

Regards
Bruce

Edit:
just seen some other comments and your photos.
The simple way is just to move the solar pv breaker to the non-rcd side of the board (assuming cable is not buried <50mm in a wall)

 

[lennyg]

Ask your installer if it is possible to move the circuit to the non-RCD protected side of the board. It may be the case that the way he has wired the installation means that it requires RCD protection - if not, then this is a very simple solution.

In what situation would it require RCD protection? This is where my knowledge becomes a little vague. My problem with asking the installer at the moment is that I want to understand what I am talking about because I think there is an element of bluff in some of the things I'm being told. If they have wired incorrectly I want to be fully aware of what it should be.

I thank you all for the swift responses already.

 

[BruceB]

In what situation would it require RCD protection?

That can be a complex answer, but looking at the photos you have provided so far then in your case I suggest only if the cable from the inverter to the consumer unit is buried less than 50mm deep in a wall rather than being surface run or in trunking.

 

[SolarCity]

In what situation would it require RCD protection? This is where my knowledge becomes a little vague. My problem with asking the installer at the moment is that I want to understand what I am talking about because I think there is an element of bluff in some of the things I'm being told. If they have wired incorrectly I want to be fully aware of what it should be.

What your installer has done, while not ideal, is actually a common problem. They may not be aware that installing on a shared RCD is a problem and as I said before, I have made the same mistake previously. It doesn't necessarily mean they have done a bad job so just keep that in mind when you speak to them.

 

[lennyg]

What your installer has done, while not ideal, is actually a common problem. They may not be aware that installing on a shared RCD is a problem and as I said before, I have made the same mistake previously. It doesn't necessarily mean they have done a bad job so just keep that in mind when you speak to them.

Thanks....