result of surveilance visit

[moggy1968]

Had my surveilance visit today. was actually my part P but on one of my solar installs so took the opportunity to ask about some of the issues that have been raised on here. Happy to post the ones I was wrong about!!
This was an ELECSA assessment.

DC isolators - it is acceptable to use the cut out on the inverter (a la SMA pull out) in lieu of a proper isolator. I will continue to use isolators though as it provides a visible means of isolation recognisable to all, PV trained or not.

Array earthing - he maintained earthing array is only required in areas of increased risk of lightening strike, even on transformerless inverters, and that the DTi flow chart was widely miss-interpreted. This suprised me a bit as the flow chart seems pretty conclusive to me!

AC Isolation - Using the double pole isolator on the fuse board as means of isolation is not acceptable as it must be securable by a generally available locking device (i.e. padlock) although this is likely to change in the future we must install to the current regs. 2 isolators must be used where the inverter is in a different room to the DB.

RCDs - providing you can get a statement from your inverter manufacturer that there is no leakage of DC onto the AC side you do not need a type B RCD, a type A is acceptable (apparently quite a few manufacturers do supply this).
Although it is unlikely the inverter will back feed onto the bussbar there is no conclusive engineering evidence as yet so the PV array should not be sharing RCDs with other circuits if a disconnection time of less than 5 seconds is required.

Your schematic should go in the meter cupboard, not by the inverter or DB, unless the mains comes in there of course.

Roof Surveys - He would not require copies of roof surveys but your expected to show that you have considered structural and wind loadings.

SMA inverters - The SMA inverter onsite (3000HF) was reconnecting too quickly, even though the country dials are set to G83 UK, has anyone else had this? It should take 3 minutes but actually takes less than a minute.

hope that helps, but possibly not because the different assessors can't seem to agree what they want!!

 

[Noshocks]

You shouldent set the dial switches to G83 as it overides the firmware settings, giving you G83 but omitting extra protectioin settings, its written in the handbook somewhere. I always set the switch to english, A i think, switch on and check it says G83, firmware would have been set to UK settings at SMA. Having said that if its set for another country and then imported into UK then you havent got much choice!

 

[moggy1968]

I suggested that to the assessor and he wouldn't have it!
He says G83 applies elsewhere, not just the uk so just because it says G83 and is in English doesn't mean it's UK G83 spec.

 

[edexlab]

Sounds to me as though he thinks earthing the array is for Lightning protection

I think he might be misinterpreting the DTI guide a bit, the trouble is a lot of installers like myself rely on these guys for a bit of guidance here and there , and they're not always right.
I had a discussion with my area engineer about Pv related issues I wanted to try and clarify and he was under the same impression about the earthing of arrays
So I showed him excerpts from the Planning and installing pv book, the DTI guide and some manufacturers info etc and to be fair he admitted he was wrong with some of his advice and said he'd been on the NICEIC pv course (no surprise there then)
and was a bit annoyed about some of the inaccurate info he'd been given and was going to do his own research and speak to the powers that be, hope he gets somewhere with that.
This bloke is always spot on with the advice he gives about electrical issues and is obviously a very experienced /qualified engineer
it just goes to show you just can't blindly trust others to get things right and anything you are told you should check for yourself.

Ps He said the same re the ESS switch but having never actually seen one until the assessment
he said he would still recommend fitting Isolators simply because they were more visible.

 

[Gavin A]

that NIC PV course is a joke... well, I guess it depends who's doing it, but I sent my 2 electricians on it a couple of days after the release of the consultation doc for version 3 of the DTI guide and he was teaching from that as if vs 2 never existed, and badly misinterpreting it anyway.

He had them convinced that they actually had to earth every single array we ever did from now on because he'd obviously entirely misread it. Fair few other things he got wrong, as well as basic stuff like not teaching them that they needed to have the DC isolator installed before starting on the panels.

Glad I spent that money getting them properly trained up. Quite worrying really tbh.


eta - then again, I had a gas engineer doing my PV reassessment.