I agree with the importance of good training however I am not sure I see the level of danger that you are suggesting.

Most countries other than the UK allow power sockets in bathrooms. There doesn't appear to be a higher accident level in these lands.

Many countries have far lower electrical installation standards. On one Chinese building site I complained about a twisted and taped joint in a 400V 3phase cable being out in the rain. They considered this to be resolved by putting an upturned plastic bucket over it.

Solar panels on roofs have two intrinsic risks, working at height, and they can't be switched off, you just have to wait for it to get dark. I would suggest that injurys due to falls from height are much more common than electrical accidents.

What are you considering to be dangerous and are there any accident statistics?

I'm still confused as to why you think this is any different to any other electrical installation work.  For any genuine component, there is likely to be a cheap Chinese copy available from the more dubious outlets.

You describe yourself as a certified and authentic EE (not Power btw). What do you mean by certified?

a) What are the special conditions for DC ELV systems? Current ratings are the same as AC and only as you get above 24V you need to think about arcing when switching. When you get above ELV arcing is more of a problem. The largest DC power supply I work with is 15kV 15A which does require thought and care when testing as well as in design.

b) What is the relevance to Solar PV?

c) Yes, my employer manufactures Crosslinked Solar cable to meet the various national specifications so I am quite aware of the requirements and I am quite conversant with electrical design and current ratings. I have been previously involved in various aspects of cable testing, short circuit performance where the conductor can reach 250°C is quite spectacular, not something I would do in my shed.

It feels like there's at least two different subjects being discussed here.

First one: is there a danger with DIY solar installations? Yes, quite possibly - just as there is with any DIY electrical installation (or indeed any DIY building work).  Is this managed in theory (in the UK)? As I understand it, yes it is, as DIY solar installations should be managed by Part P (note: see my second point before hurrumphing at whether the local authority is competent to asses these). Is it managed in practice (in the UK)? Probably not, there probably are a number of DIY installations which have not been notified under Part P, which will only come to light when the owner tries to sell the house or when they try to make an insurance claim. Again just as with other electricity, and indeed all building, work. Is it putting people at an unacceptable level of risk? I suspect the people to ask about that are the UK fire service and insurance companies, these are the bodies that would see the impact. But remember we are talking about installations which are already (as I understand it) illegal, there would need to be evidence of a very considerable level of risk to justify any higher level of enforcement. 

Second one: do professional installers and assessors, including local authority building controllers, have sufficient and up-to-date information and training to design, install and assess installations? So I think this comes down to: Do we have evidence that the BPEC 0018 Level 3 Award and the underpinning IEC 60364-6, IEC 60364 and IEC 62548 are inadequate to manage the risks? (Noting that BPEC 0018 teaches that the design and equipment must meet those standards). I'm not arguing that they are or aren't, I don't know. But given they are in place, I think we'd need evidence of failures in the UK to argue that they are not working. In "inadequate" I'm including the thought as to whether this or comparable courses are / should be mandated for installers and assessors - mandatory training is always a hot topic on these forums for for and against arguments!

And yes, I do agree there's a challenge that travel may be required to attend an appropriate course. It does seem that at lot of FE training has been rolled back from local delivery. But that feels like a separate topic again.

Roger B said:

You describe yourself as a certified and authentic EE (not Power btw). What do you mean by certified?

a) What are the special conditions for DC ELV systems? Current ratings are the same as AC and only as you get above 24V you need to think about arcing when switching. When you get above ELV arcing is more of a problem. The largest DC power supply I work with is 15kV 15A which does require thought and care when testing as well as in design.

b) What is the relevance to Solar PV?

Apologies about the language in the commentary of this short video but it does illustrate some of the points that have been discussed here: www.facebook.com/.../3507234699527923

I think the fact this kind of thing goes on is an issue.

And if you have a fault L+-L- before a combiner box or inverter, say because of vandalism or (possibly unforeseen) mechanical damage, it's the only way of stopping current flow with the way PV is designed ... and yes, there's perhaps a discussion on whether that is in line with "general parts" Part 4 and 5 of BS 7671 ...

Hello Graham,

I think that the replies have got a little confused. I was referring to Rob Tes’s post where he was talking about the quality of Lucar connectors. Thank you for the video, it would be useful to know what voltage and current they were interrupting. I have previously wondered that as we are dealing with an almost constant current supply whether shorting switches would be a better option that isolators as  the first action on small systems.

Roger B said:

a) What are the special conditions for DC ELV systems? Current ratings are the same as AC and only as you get above 24V you need to think about arcing when switching.

www.youtube.com/watch

gkenyon said:

short video but it does illustrate some of the points that have been discussed here: www.facebook.com/.../3507234699527923

Yes seen that one, notice the crappy electrical pliers, barely capable of cutting 6mm solar cable.  A proper pair of cable cutters should be essential safety kit, long handle snip thru in a heatbeat.  Its the method of last resort and amateurs dont learn these things (plus PPE of course), gloves, goggles and makes sure your overalls arent flammable with spilt liquids)

Roger B said:

shorting switches would be a better option that isolators a

good way to start a roof fire?

Andy Millar said:

So I think this comes down to: Do we have evidence that the BPEC 0018 Level 3 Award and the underpinning IEC 60364-6, IEC 60364 and IEC 62548 are inadequate to manage the risks? (Noting that BPEC 0018 teaches that the design and equipment must meet those standards). I'm not arguing that they are or aren't

Hi Andy Im not familiar with BPEC (plumbers and gas fitters?).  Cant find much about them or independent credentials. They seem very coy about what their courses offer and no indication of costs?  Looks like the kind of outfit which a large Corp would use for special training for specific site needs?  Not for the Sole trader leccie? Doesnt seem like too much would be devoted to the tangled web of Regs IEC etc.?  Anyone any experience using BPEC .  The CEO is a tradesman plumber.  It has a very professionally convoluted website making a lot of claims which I cant verify as yet.

But I found this

BPEC Award Solar PV Installer & BPEC Electricity Energy Storage Systems Course

£895.00 + VAT

Rob Tes said:

good way to start a roof fire?

Not really.  Solar panels are inherently current limited by the way they work.  In normal operation, they will be run at a current close to their short-circuit current.  So in the case of a short, nothing much happens to the panel, and the wiring needs to be able to handle that current anyway.

Rob Tes said:

good way to start a roof fire?

Not really.  Solar panels are inherently current limited by the way they work.  In normal operation, they will be run at a current close to their short-circuit current.  So in the case of a short, nothing much happens to the panel, and the wiring needs to be able to handle that current anyway.

Simon Barker said:

So in the case of a short, nothing much happens to the panel, and the wiring needs to be able to handle that current anyway.

Agreed, but it's not just about protection against overcurrent. Arc can still form, or the DC cabling must be made safe to work on.. Detecting it at the inverter end will alert someone to the fault, but if all they can do is cut cables, that's no good !

We must do better and provide a means of disconnecting the source, in line with the requirements of the General Rules of BS 7671, so it's safe to work on cables and connectors which can't be disconnected on-load either .