Solar panel circuit MCB size?

[Leesparkykent]

Yes solar PV should be protected by an RCD. Some manufacturers state 30Ma some state 100Ma. The solar array is outside, usually roof mounted so it requires RCD protection. I always install a new 2 way RCD board separate from the domestic CU to avoid nuisance tripping. The PV installation can have quite a lot of earth leakage and if it's connected to the same RCD as the house it can cause problems. Separating the two installations can make life a lot easier with regard to nuisance tripping.

what has the RCD in your 2-way consumer unit got to do with the DC side of things= NOTHING lol

and i can probably rest assure you are not fitting type b RCD's as you dont have to!

 

[infinity]

Rihco what a load of tish! It does not require RCD protection at all, we always design the RCD out so surface mounted or alike then no nuisance tripping can occur. An inverter can cause nuisance tripping on its own RCD as well I've seen it, and changed it. RCDS with solar PV Is usually poor design Tbh

 

[Richo77]

I follow manufacturers instructions. And also the MCS inspectors have instructed us to it this way.

 

[Leesparkykent]

I follow manufacturers instructions. And also the MCS inspectors have instructed us to it this way.

Manufacturers instructions for the inverter or panel/dc cable/dc plugs?

 

[Gavin A]

I follow manufacturers instructions. And also the MCS inspectors have instructed us to it this way.

You've misread the instructions, and the MCS inspector doesn't know what he's talking about - many of them don't.

I had one attempting to insist that I should have earth bonded the array frame on an isolating transformer inverter system under the old rules about bonding the frames for TL inverters only. He was a former gas fitter who'd never installed a solar PV system.

 

[Gavin A]

If regulations in the country of installation stipulate an external residual current device, you must use
a device with a tripping threshold of 100 mA or more.

that's SMA's instructions relating to RCDs.

 

[SibertSolar]

omg....where's that popcorn smiley...

 

[infinity]

My MCS assessor last year was a plumber! No electrical quals or experience what so ever.
But he did know how to navigate a QMS manual

 

[Gavin A]

The head technical person from one of the MCS schemes rang me one time a while back because I'd had a pop at their assessors on here (if I remember right).

They were of the opinion that their assessors really knew what they were doing because they made sure they'd all done a minimum of 5 solar PV installations before they'd give them a job as an assessor.

IIRC I pointed out that our apprentice had done around 100 installs.

Boils my **** that they all consider it acceptable to have folk assessing us who we'd not class as competent to even supervise the most basic of domestic installs*.

Apparently this isn't something that can be discussed at MCS though, 'it's an enforcement issue'.



*not tarnishing all assessors with the same brush, there are some highly competent assessors out there as well, it's just the minimum standards that are set far too low.