new to this so I need some advice please

oldtimer · Mar 5, 2012

Guys as the title says I am new to this I recently stripped out a 10 way 3036 wylex DB and changed it for a 15 way unit because the customer was going to get a PV system installed at a later date so I was asked to supply a 16 amp type B breaker for them to use at a later date. Now I set the DB up with 2 outputs after the main switch and then 2 RCDs with 6 ways on one and 7 on the other as for the 2 ways after the main switch I fitted a 20A RCBO (for the garage supply) and the 16A type B for the PV I also said to the customer are you sure they asked for a 16A type B breaker and not a 16A type B RCBO and the reply was no its a 16A type B breaker.

Ok I said so I have the house split accross 2 RCDs and the garage supply on its own independant RCBO then the customer phones to say they have moved the 16A breaker to one of the RCD sections of the DB ??? so my question is why did they not specify a 16A RCBO so that it would be seperate from the rest of the house or in other words if it developed a fault then all it would do is trip its own RCBO yes

SolarCity · Mar 5, 2012

The big issue here is that the inverter will affect disconnection times on your RCD - the RCD will trip yet the inverter may be supplying voltage for another 5 seconds.

It would make more sense to have the 16A as you originally had it - non-RCD protected. And then make sure that your cable run means that you don't need it.

Noshocks · Mar 5, 2012

I agree, you set the board up exactly how I would have expected to see it if PV was to be fitted later by another electrician, they have the option of fitting an RCCB inline from this spare way or just using an MCB, it should not be operating from the RCD supplying other circuits, i would tell them that, then leave it up to them.