Am I missing something?

[HappyHippyDad]

Just had a phone call from an existing customer.

He has just had solar panels put in, along with a very large battery.

He has a single up front 30mA RCD main switch in the CU protecting all circuits. Earthing is TNCS.

The solar installer has changed the up front 30mA RCD for a 100mA RCD because after he had installed his work the 30mA RCD was tripping.

I cant believe he has done this and have told the customer to get him back to find the fault and reinstate the 30mA.

I'm not missing anything am I? It's so bad, that I am questioning myself.

 

[westward10]

No they have removed the additional protection which a 100ma device does not provide.

 

[Mikegh]

Not familiar with the solar but doesnt sound right

Can't see where u can swop a 30 for a 100 there ?

 

[littlespark]

It was an up front 30mA rcd. That has been removed and swapped for 100mA

They have taken away the 30mA that is required for additional protection on all circuits that require it.

Ideally, there shouldn’t be one rcd for everything. Split board or individual rcbo, but what they have done is leave the installation in a “less safe” condition

 

[SparkySy]

A solar company did similar to one of my customers. Removed completely the 30ma RCD as it kept tripping after they had finished the install and left it with another main switch where the RCD used to be. They did this as it was a dual rcd board so no unprotected ways! I told my customer to get them back to sort it out!
They ended up having to run a sub db with its own protection. I think the original RCD they removed was with other leakage close to its threshold before the solar was added and that was enough to trip it!

 

[Mikegh]

A solar company did similar to one of my customers. Removed completely the 30ma RCD as it kept tripping after they had finished the install and left it with another main switch where the RCD used to be. They did this as it was a dual rcd board so no unprotected ways! I told my customer to get them back to sort it out!
They ended up having to run a sub db with its own protection. I think the original RCD they removed was with other leakage close to its threshold before the solar was added and that was enough to trip it!

So the solar was downstream ? and probably adding to the standing leakage on a main rcd

Is there no standard for separate leakage protection ,or do they need a B type ?

 

[SparkySy]

Yes the solar was downstream from the RCD as there was only 1 space left in the unit. I think that was the case the solar was just enough to push the RCD over its limit!
Some PV units didn't require RCD protection as long as the cable didn't need it due to its route!
I can't say now as I haven't kept up with the PV stuff, I stopped installing it when the FIT rate dropped below about 30p per unit!
sy

 

[plugsandsparks]

No you are not missing anything but the client is...... His entire electrical system is now more dangerous than it was. We all know that the DB should have been upgraded and the PV given its own RCD protection.
Suggest Solar is turned off and 30mA RCD restored until DB is upgraded

 

[snowhead]

I wonder how many other installations this installer has done the same trick to and the customer is unaware or is unaware of the implications.

 

[HRM-ELEC]

Am I right in saying Solar should be on its own RCBO or MCB and definitely not on a shared RCD as this inverter can take up to 5 seconds to disconnect ?

 

[pc1966]

Am I right in saying Solar should be on its own RCBO or MCB and definitely not on a shared RCD as this inverter can take up to 5 seconds to disconnect ?

That is an important but different point. I have seen a PV install on a shared MCB, so the rest circuit of the circuit could get 16A from the MCB and another 16A or so from the PV under full sunlight. I.e. now 32A from an overload point of view.

OK, under fault the inverter shuts down, and this was Scotland so full sunlight is a rare event, but still...

The OP's issue is the whole installation had a 30mA RCD providing the "additional protection" needed for the likes of socket outlets, etc, and by changing that to 100mA it no longer is able to adequately protect against the risk of electric shock as someone could well have grasped something live and been unable to let go, is entering heart fibrillation, and the RCD is still not seeing its trip threshold.

Had it been a 100mA delay RCD up-front like in a TT system along with 30mA RCD or RCBO for sockets, etc, it would be fine, but now it merits C2/C3 on an EICR and basically is a stupid thing to do.

 

[Zlodej]

Am I right in saying Solar should be on its own RCBO or MCB and definitely not on a shared RCD as this inverter can take up to 5 seconds to disconnect ?

You should think of an solar inverter as another source of supply As such You are right. As even if the RCD is left as 30mA it is unable to protect devices sharing its bushbar from issues when inverter is supplying power. You can think of it like a brown wire around the RCD. the lifting the RCD rating is just an extra homeopathic remedy here

 

[GLENNSPARK]

It's a bit like the air con guys that persist in using D curve breakers on their circuits that'll never meet times...

You just know it's never seen a loop test...