- Jan 20, 2012
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- If you're a qualified, trainee, or retired electrician - Which country is it that your work will be / is / was aimed at?
- United Kingdom
- What type of forum member are you?
- Other
- If other, please explain
- Solar installer for 15 years
- Business Name
- Leeds Solar
evening all, I wondered if anyone could assist me and my spark to come to a conclusive answer on something that we're not 100% sure about.
Essentially when doing our solar installations we usually split the incoming tails using a henley block, then run a 2nd set of tails to a garage unit, usually with a 30mA dual pole RCD and 16amp single pole MCB, though sometimes we use just a dual pole 16amp MCB.
The question is around the size of tails we should be using for the solar side. A while ago our main electrician was running 25mm tails as new in all installations, but I couldn't see why this was needed and after some discussion and checking of regs etc we switched to 16mm2 tales - mostly because the 25mm2 tales were proving so awkward to fit in some of the tight spaces involved that it was taking him 3 times as long so we'd end up not finishing til after dusk, which isn't much use for testing solar panels.
We've since been using 16mm2 tales on everything for the solar side, even if it's a 100A suppliers fuse, on the basis that the circuit is protected from overload via a 16A mcb beyond the tails anyway, and this is a dedicated circuit for solar only with no load connected to it anyway, and if it was a dead short on the tales then the 100A incomer ought to blow for a dead short regardless of the size of the tails.
Apparently my spark ran this by his Elecsa assessor and he couldn't see a problem with it, but for some reason it's still bugging me a little bit - probably because we changed to using this method on my say so when my spark thought he ought to have been using 25mm2, and in theory he ought to know this stuff better than me.
Can anyone see a problem with this / spot any regs we're contravening / flaws in my logic around the use of the 16mm2 tails on a 100A suppliers fuse just for the solar circuit alone? (usually the tails are only around 500mm from the henley block)
Thanks for any sanity checking assistance on this.
ps fwiw, I'm technically part p approved for electrical work, have done 17th edition etc. but don't really class myself as a proper spark as such (though more so now after 3 years working alongside proper sparks than straight after my short sharp shock courses), and have pretty much always employed time served sparks for the bulk of the electrical work and testing, though I will do a few simple installs a year myself. I more get involved in determining the design side of the electrical work in conjunction with the sparks, and mostly manage the panel installation aspects of it, and assist with bits of the electrics if needed.
Essentially when doing our solar installations we usually split the incoming tails using a henley block, then run a 2nd set of tails to a garage unit, usually with a 30mA dual pole RCD and 16amp single pole MCB, though sometimes we use just a dual pole 16amp MCB.
The question is around the size of tails we should be using for the solar side. A while ago our main electrician was running 25mm tails as new in all installations, but I couldn't see why this was needed and after some discussion and checking of regs etc we switched to 16mm2 tales - mostly because the 25mm2 tales were proving so awkward to fit in some of the tight spaces involved that it was taking him 3 times as long so we'd end up not finishing til after dusk, which isn't much use for testing solar panels.
We've since been using 16mm2 tales on everything for the solar side, even if it's a 100A suppliers fuse, on the basis that the circuit is protected from overload via a 16A mcb beyond the tails anyway, and this is a dedicated circuit for solar only with no load connected to it anyway, and if it was a dead short on the tales then the 100A incomer ought to blow for a dead short regardless of the size of the tails.
Apparently my spark ran this by his Elecsa assessor and he couldn't see a problem with it, but for some reason it's still bugging me a little bit - probably because we changed to using this method on my say so when my spark thought he ought to have been using 25mm2, and in theory he ought to know this stuff better than me.
Can anyone see a problem with this / spot any regs we're contravening / flaws in my logic around the use of the 16mm2 tails on a 100A suppliers fuse just for the solar circuit alone? (usually the tails are only around 500mm from the henley block)
Thanks for any sanity checking assistance on this.
ps fwiw, I'm technically part p approved for electrical work, have done 17th edition etc. but don't really class myself as a proper spark as such (though more so now after 3 years working alongside proper sparks than straight after my short sharp shock courses), and have pretty much always employed time served sparks for the bulk of the electrical work and testing, though I will do a few simple installs a year myself. I more get involved in determining the design side of the electrical work in conjunction with the sparks, and mostly manage the panel installation aspects of it, and assist with bits of the electrics if needed.
