Move Meter From Consumer Unit Because Of Problem Tripping

[thebuckets]

Hi I'm an out of trade but time served Electrician looking for a bit of advice.

I had a solar PV install a few years a go and they placed the meter in my existing  consumer unit through a 16A MCB.

Im getting an intermittant tripping of my RCD and have had all ccts isolated at one time or another and its still happening so suspect it may be my inverter tripping it out.

To avoid changing the whole Consumer unit can I just remove the meter and MCB (isolater first of course) and place them in a garage type 2 way consumer unit (non RCD) and feed it into neutral blocks to connect it to the main CU and meter? or does it need to be through an RCD?

PV install would then run:

array, dc isolator, inverter, AC isolator, (meter, MCB, main switch, in garage style consumer unit) meter tails to neutral blocks to connect it to meter and main CU

Many thanks in advance

 

[ProDave]

You can do that, and arguably it's better.

But the rcd in the garage unit will trip instead as you have not tested for or made any attempt to fix the fault that's causing the rcd to trip.

 

[Andy™]

if the solar is on an RCD that also feeds another circuit, then it is non-compliant and installed by cowboys

 

[steptoe]

^^^^^^

What he said,

Plus,

Not all inverters will work on all RCDs 

Deffo sounds like a cowboy install though 

You can do that, and arguably it's better.

But the rcd in the garage unit will trip instead as you have not tested for or made any attempt to fix the fault that's causing the rcd to trip.

May just be an inverter and RCD combination that are non compatible though Dave 

 

[Lurch]

if the solar is on an RCD that also feeds another circuit, then it is non-compliant and installed by cowboys

Usually yes, but would depend on disconnection times.

 

[thebuckets]

^^^^^^

What he said,

Plus,

Not all inverters will work on all RCDs 

Deffo sounds like a cowboy install though 

May just be an inverter and RCD combination that are non compatible though Dave 

do I need an RCD on the consumer unit that is purely for the Solar PV?

 

[Andy™]

Usually yes, but would depend on disconnection times.

it cannot comply if solar shares an RCD. inverter can take upto 5s to shut down on power failure, so other circuits on same RCD could take 5s longer to disconnect than their max permitted time

 

[Lurch]

do I need an RCD on the consumer unit that is purely for the Solar PV?

Depends on the wiring method.

 

[thebuckets]

if the solar is on an RCD that also feeds another circuit, then it is non-compliant and installed by cowboys

Seen a few differing opinions on that on here.

They were meant to come back and fit a stand alone meter but never did and I let it slip.

It was installed in Dec 2011 just before the price drop on FITs and i was caught between getting this company in or missing the cut off date if I had done my prefered option of doing the install myself

 

[steptoe]

do I need an RCD on the consumer unit that is purely for the Solar PV?

depends on whether or not the PV needs an RCD

 

[thebuckets]

Depends on the wiring method.

care to elaborate?

 

[Andy™]

Seen a few differing opinions on that on here.

They were meant to come back and fit a stand alone meter but never did and I let it slip.

It was installed in Dec 2011 just before the price drop on FITs and i was caught between getting this company in or missing the cut off date if I had done my prefered option of doing the install myself

so youre quite happy to knowingly have a non-complaint and potentially dangerous instal, but at least youre getting paid more for it. how much is a life worth these days?

 

[steptoe]

Seen a few differing opinions on that on here.

They were meant to come back and fit a stand alone meter but never did and I let it slip.

It was installed in Dec 2011 just before the price drop on FITs and i was caught between getting this company in or missing the cut off date if I had done my prefered option of doing the install myself

I doubt very much you would have got any FITs if you had installed it yourself,

the qualifications you need, along with all the paper trails, insurances, and registrations make it horrendously financially unviable for DIY installs that qualify for FITs

 

[thebuckets]

sure I read on here that sharing the RCD was compliant at the date of my install. Got a fronius Inverter (think its transformerless?) no problem fitting an RCD in the new dedicated board, if it trips itll confirm my opinion that it is the PV that is causing the tripping.

it seems to happen several times in a row usually 7.30-8.00 am then nothing for a few days

 

[Andy™]

it has never been compliant

 

[steptoe]

sure I read on here that sharing the RCD was compliant at the date of my install. Got a fronius Inverter (think its transformerless?) no problem fitting an RCD in the new dedicated board, if it trips itll confirm my opinion that it is the PV that is causing the tripping.

it seems to happen several times in a row usually 7.30-8.00 am then nothing for a few days

its never been compliant

sounds like your inverter is tripping the RCD on start up,

what size and type RCD, and what model inverter?

 

[thebuckets]

so youre quite happy to knowingly have a non-complaint and potentially dangerous instal, but at least youre getting paid more for it. how much is a life worth these days?

woah there fella!

I got a registered firm in to do my PV install, got it signed off, tested and FIT sorted. This is in my home so the suggestion that I would bodge a job through for cashg whilst potentially risking my family is offensive.

I|ve asked for advice on my proposed Mods if you can contribute to that great...

its never been compliant

sounds like your inverter is tripping the RCD on start up,

what size and type RCD, and what model inverter?

now this seems to be the help im after. i'll dig the info out and post tomorrow if thats ok? cheers

 

[Andy™]

then get them back to correct their bodge

 

[thebuckets]

then get them back to correct their bodge

I would but as its 4 yrs down the line I think they may have gone to the wall

its never been compliant

sounds like your inverter is tripping the RCD on start up,

what size and type RCD, and what model inverter?

its a Wylex WSES2/100 100A 30mA RCD invertter is a Fronius TL 3.6

 

[binky]

Ok Andy, there's nothing in the standards for fitting solar that says you can't share an RCD with the solar installation, so you can't just start calling them cowboys and bodgers, but as we have discussed here on this forum it isn't a good idea. In the original guidlines from the NICEIC they even suggested tapping into and upstairs ring main - that changed pretty quickly. If they were cowboys they would have fitted ac heapo Chinese inverter.

Trouble with inverters is that on start up and shut down they can 'chatter' the AC connection relay, which RCDs do not lke, especially when shared with other circuits. I prefer to install a solar circuit on a non-RCD protected circuit, but as pointed out, the requirements for an RCD depends on the AC cable run, ie is it buried less than 50mm into a wall etc etc as is compliant with the current edition of BS7671. On TT systems I have fitted an RCD, not shared with any other circuit, and it has been fine. The fact that your system is starting to play up after several years suggests that something else is starting to fail - probably an appliance. Fronius is a top quality inveter, one of my favourites, and not some cheapo Chinese crap. made in Austria to brick outhouse standards!

Your proposal to rearrange the solar onto a garage mini CU is absolutely fine and a cost effective option ( as long as your meter blocks are your side of the normal electric meter). It would be better on a 20A MCB and run in 4mm if possible - reduces cable losses for a few quid of cable. 2.5mm is fine, but I like to max system performance.  The inverter, I am assuming an IG TL 3.6, is designed to be 16A limited, now it will only output max 16A for a few hours, but I've always felt the circuit would be better on a 20A rather than running at the max value of the MCB at 16A