Insulation test solar array

[PeteC]

Sorry yes 120 should be 250.

BS 62446 is a bit of a bible for PV. I've heard that Liverpool main library have all BS copies on line for free if your a member! (costs to become a member)I think our GB regulators have been spending to long getting on top of this, after all, were importing IEE regs in PV that have been refined over years.

Black arts~ bulls**t. The guys you presume are in the know may not have a clue. I asked a new PV training provider about the testing measures and he stumbled! Bums on seats scenario.

The concerns in testing are short-circuiting the DC and arcing, along with high DC voltages that might go with the system., and then the insulation resistance charge~ hanging off the edge of a roof is not ideal especially at 1000v. Neither is curious clients and their kids. Testing recommends live conductors (combined) to each part of the frame~ ie 2 rows of modules = 4 roof bars = 4 tests.
Individual live conductors to earth is a curious one. If not classII then a potential may be picked up and the meter cut out as it's meant to if over 50v. Spoke to the guys at Megger last year over this, and they couldn't see how it could be achieved. Test with AC voltage? Be interesting to hear from anyone who knows the europeans method of testing.

 

[gr7]

Hampshire library membership also gives full online access to the BS website (not for commercial use, reference only) and is free to join if you are lucky enough to live in Hampshire. I suspect all UK libraries have a similar arrangement.

 

[edexlab]

"Individual live conductors to earth is a curious one. If not classII then a potential may be picked up and the meter cut out as it's meant to if over 50v."

I'm not sure what you mean ?

if your doing insulation resistance test between + or - (the same conductor) then you would have the two ends of the string disconnected
so that no circuit is there ,no circuit no voltage , test between + to earth and - to earth .

 

[PeteC]

Thats how the IEE regs state it as a second test method (with open circuit the GS38 meter detects the Voc and cuts out). Maybe it applies to main DC cable runs only ie with strings isolated as in our standard insulation tests. Or test applies for middle grounded systems (3wire systems). Theory may be that test current can't flow through modules and their cells anyway as not part of semi-conductor flow. I haven't been able to get any info. on this testing method, does anyone know what it applies to?

 

[SRE]

Sorry yes 120 should be 250.

BS 62446 is a bit of a bible for PV. I've heard that Liverpool main library have all BS copies on line for free if your a member! (costs to become a member)I think our GB regulators have been spending to long getting on top of this, after all, were importing IEE regs in PV that have been refined over years.

This sounds like something we could do with - has anyone actually got a copy - is it worth it?