Main RCD trips

[BruceB]

hold up, I just realised it was you who was arguing that it was allowed by the regs last time we had this discussion, and me arguing the other way.
FWIW you convinced me it was allowed, though still not something I'd recommend. Did I convince you it wasn't?

Are you sure?  I have been arguing this point for months as far as I recall.
The other point I make regularly is if you can avoid it then do not use an rcd at all.  It is one more point of failure for little extra protection.

The only thing I remember changing your mind on is definition of TIC

[BruceB]

The way I read the extract from Bruce is that the disconnection time would be 0.5 seconds in most cases, .................

You might think so at first reading, but the inverters I use mostly (SMA and Power One) make use of the 5s allowance if you look at their G83/1 test results

[Jeff John]

The property has an earth rod, as far as I remember. I'll need to check if it's a 30mA or 100mA - would the 30mA unit be likely to trip? I've never heard of this problem before. From what the customer has said, it's the RCD that trips - ie the whole house power goes down - NOT just the PV circuit.

If it's a TT system then some circuits should be RCD protected others not, the 4000TL should be protected by a 100ma RCD/RCBO independant to the rest of the supply. although I have never had any problems with a 30ma trip as long as its independent to the main consumer unit. Fit a small garage consumer unit off a Henlly block or put an RCBO in the CU but wire it off the (switched side) off the main switch,(live & neutral).   

[RobertReadman]

The SMA 4000TL should be wired to a 100mA RCD type B! if an RCD is going to be installed.
I have mine to a 30mA RCBO as all UK RCBO's have to be DC sensing (what a type B RCD does).

I don't think many installers know about type B RCD's and just install to a type A, or get confused with type B MCB's.

*sigh* anyway if you google for type A rcd vs type B you will find info...
http://www.doepke.co.uk/rcd/rcdB.html

A split load board, will NOT have type B RCD's.
Last time I checked they were around £300 each. RCBO's are only around £25.

In the thread we havent found out if "It's started tripping the main switch every time it powers up in the morning"
Is actually tripping the main switch, or just one RCD (type A or B?) or tripping the MCB? or if an RCBO with an indicator (like Hager ones have) if it was the MCB part of the RCBO that tripped or the RCD part of the RCBO that tripped. (The indicator window that people thing is red / green for on / off, actually lets you know if it was earth fault or overcurrent).

Sounds to me like the wiring needs looking at, the DTI guide needs looking at, and earthing needs looking at.