jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
So it was recently brought to my attention that this type of disconnect is insanely cheap compared to what we've been using to comply with the grouped disconnect requirement when an inverter is not near the point of interconnection. 690.15 in the 2014 NEC. The safety switch has always been what I've seen in the solar industry, and I've always just done what was done before. But there's a lot of money to be saved here, so I'm asking myself, if it's good enough for the air conditioning guys, why not good enough for solar inverters?
(Before anything else: this thread does not pertain to disconnects required by utilities. Just NEC requirements.)
Anybody using these? (for small inverters, up to 48A output)
Anyone aware of a good reason not to use them?
Thoughts:
First, 705.22 includes:
It seems like perhaps this rules out a pull-out type disconnect, but we'll always have another disconnect that can comply with 705.12. This is just to comply with 690.15. (Also, is there a good reason that 705 should rule out pull out disconnects?)
Second, the 2017 NEC changes things up quite a bit in 690. We now have similar language as above in 690.15(D), except it says "externally operable without exposing the operator to contact with energized parts..." (emphasis added). It also includes "A load break fused pull out switch" among the list of options for an 'equipment disconnecting means'. I find this, er, interesting. First, why must the pull out switch be fused? Second, if a type of pull out switch is allowed, then do pull out switches not expose the operator to live parts? Or does a pull out switch "expose the operator to live parts" but not expose them "to contact with energized parts"?
Does this language about exposure to live parts appear in any non-solar related requirements for disconnects elsewhere in the code?
Opinions and thoughts appreciated.
(Before anything else: this thread does not pertain to disconnects required by utilities. Just NEC requirements.)
Anybody using these? (for small inverters, up to 48A output)
Anyone aware of a good reason not to use them?
Thoughts:
First, 705.22 includes:
" the disconnecting means shall consist of ... switch(es) or circuit breaker(s) with the following [feature]:
...
(2) Externally operable without exposing the operator to live parts...
It seems like perhaps this rules out a pull-out type disconnect, but we'll always have another disconnect that can comply with 705.12. This is just to comply with 690.15. (Also, is there a good reason that 705 should rule out pull out disconnects?)
Second, the 2017 NEC changes things up quite a bit in 690. We now have similar language as above in 690.15(D), except it says "externally operable without exposing the operator to contact with energized parts..." (emphasis added). It also includes "A load break fused pull out switch" among the list of options for an 'equipment disconnecting means'. I find this, er, interesting. First, why must the pull out switch be fused? Second, if a type of pull out switch is allowed, then do pull out switches not expose the operator to live parts? Or does a pull out switch "expose the operator to live parts" but not expose them "to contact with energized parts"?
Does this language about exposure to live parts appear in any non-solar related requirements for disconnects elsewhere in the code?
Opinions and thoughts appreciated.