label citations.

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
I think you've complied with the letter of 705.10 but most jurisdictions I've seen enforcing this expect a map. Arguably a map better draws attention to the need to go looking elsewhere for power sources. That said, it's pretty unclear what the specific gripe is, I'd probably ask. (Also the requirement for both dc and ac discos to be labeled is over-interpretation in my opinion.)

As far as the terminals on both sides label, try to explain that they are just wrong? Use manufacturing documentation? I can't tell you how many times I've applied that particular label to just avoid continuing an argument with an inspector who refused to get it. I managed to successfully educate maybe 10% of the inspectors I discussed it with. (And now that I'm installing more energy storage systems where that label's wording is actually true, I'm even more resentful of the stubborn bastards who forced me to apply all those aforementioned labels that are still out there crying wolf.)
 
I think you've complied with the letter of 705.10 but most jurisdictions I've seen enforcing this expect a map. Arguably a map better draws attention to the need to go looking elsewhere for power sources. That said, it's pretty unclear what the specific gripe is, I'd probably ask. (Also the requirement for both dc and ac discos to be labeled is over-interpretation in my opinion.)

As far as the terminals on both sides label, try to explain that they are just wrong? Use manufacturing documentation? I can't tell you how many times I've applied that particular label to just avoid continuing an argument with an inspector who refused to get it. I managed to successfully educate maybe 10% of the inspectors I discussed it with. (And now that I'm installing more energy storage systems where that label's wording is actually true, I'm even more resentful of the stubborn bastards who forced me to apply all those aforementioned labels that are still out there crying wolf.)
So what is a valid place/situation for the "both sides may be energized" label?
 

JoeNorm

Senior Member
Location
WA
So what is a valid place/situation for the "both sides may be energized" label?
I think it's outdated for the most part. Used to be true before module level controls were in place and straight DC came off the roof to the disconnect. That's not really how residential PV systems work anymore.
 
I think it's outdated for the most part. Used to be true before module level controls were in place and straight DC came off the roof to the disconnect. That's not really how residential PV systems work anymore.
Well we do lots of ground mounts with no module level. So of course the module side of the DC disco is hot, but why would the inverter side be?
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
So what is a valid place/situation for the "both sides may be energized" label?
I see these labels on a lot of disconnects just after the meter when I go out to test them (anti-islanding).
I don’t understand why it’s there. Looks like to me the invertor is where the “both sides may be hot” sticker should be.
my understanding is until the invertor phase locks and times out 300 seconds there is nothing sent to the disconnect at the meterbase (or panel)

I’m certainly not an expert by no means in the PV installs, but some of the labeling I see seem to create more confusion.

Am I missing something here I should know regarding the testing?
 
I see these labels on a lot of disconnects just after the meter when I go out to test them (anti-islanding).
I don’t understand why it’s there. Looks like to me the invertor is where the “both sides may be hot” sticker should be.
my understanding is until the invertor phase locks and times out 300 seconds there is nothing sent to the disconnect at the meterbase (or panel)

I’m certainly not an expert by no means in the PV installs, but some of the labeling I see seem to create more confusion.

Am I missing something here I should know regarding the testing?
I am with you that much of the PV labeling is overboard and just causes more confusion. Like JB said, I think seem most don't fully understand or misapply these and they just end up getting slapped all over the place "just in case".
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
So what is a valid place/situation for the "both sides may be energized" label?
I can think of several examples where the label would or could be appropriate...

Definitely appropriate:

1) In an older-school off-grid system where PV panels are directly paralleled with a battery (and PV charge controller passes voltage through when energized, then an open disconnect for either PV or battery is energized on both sides when only one source is disconnected.

2) In a utility scale PV system where, say, you had multiple DC combiner boxes connected in parallel to, say, a common bus on a central inverter, then a disconnect at one combiner box will be energized on both sides unless all the combiners are disconnected from the common bus.

3) Where an AC output energy storage system with backup capability is connected to the grid but still outputs voltage when disconnected, the AC disconnect should have this label. e.g. Powerwall or Enphase Encharge.

Borderline appropriate:

4) There might be some inverters where capacitor discharge takes a while, meaning that a DC disconnect might still have some live voltage on the inverter side for some seconds after the DC disco is opened. Maybe this applies to your case here? But seems very, very persnickety if it's not longer than it takes to pick up a screwdriver.

5) Where you have AC and DC coming into an inverter enclosure, as in your case, I have found it somewhat appropriate to apply the label as a kind of 'don't touch this if you don't know what you're doing' warning. The idea being that someone unqualified may think that turning off the switch de-energizes one of the sets of conductors entering the enclosure, as would be true for many enclosures, but not in this case. But this is more of an extra-diligence idea than something that is code required. And another label such as 'dual power sources' could serve the same purpose.

As far as the 'crying wolf' applications I mentioned earlier, I mostly was referring to AC disconnects or panelboards where interactive inverters were connected. So many inspectors just don't have a clue about UL 1741 and normal inverter anti-islanding.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
I see these labels on a lot of disconnects just after the meter when I go out to test them (anti-islanding).
I don’t understand why it’s there. Looks like to me the invertor is where the “both sides may be hot” sticker should be.
my understanding is until the invertor phase locks and times out 300 seconds there is nothing sent to the disconnect at the meterbase (or panel)

I’m certainly not an expert by no means in the PV installs, but some of the labeling I see seem to create more confusion.

Am I missing something here I should know regarding the testing?
If you are testing at a disconnect for anti-islanding function, then almost by definition that disconnect is not an appropriate place for the 'energized on both sides' label we are discussing. So your understanding is correct, and I don't think you're missing anything. If the disconnect passes your test, then the label is not true. If it fails your test, then either the system was installed incorrectly or you are testing the wrong disconnect (e.g. in systems where there maybe be an energy storage disconnect somewhere on the other side of a micro-grid interconnect device.)

In other words, what you're seeing is exactly what I meant above about stickers that 'cry wolf' when there's no wolf about. And I completely agree about them creating more confusion.
 
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