1000 Volt DC disconnects Solar Edge inverters

[harborrick]

We have some 33kw inverters 480v. Ac and 1000v DC
Utility wants DC disconnects on the line side of inverter. Even tho inverters have DC disconnects.
So we usually just disconnect the positive side and negative straight to inverter.
Since positive I believe is 450 volts to ground we could get away with 600v disconnects.

If we need 1000v disconnects open blade what will you all use? And where to buy?
Thanks in advance

 

[jaggedben]

Square D HU361RB should be widely available. Or look up Industrial Controls Direct for European style plastic enclosure discos, if you don't actually need open blade.

Your utility seems kinda behind the times.

 

[pv_n00b]

I've not heard of any utility directing the design of a PV system outside of the main AC disconnect and the interconnection. If a utility started to tell me how to do PV design I would politely remind them to stay on their side of the service point.

 

[ggunn]

I've not heard of any utility directing the design of a PV system outside of the main AC disconnect and the interconnection. If a utility started to tell me how to do PV design I would politely remind them to stay on their side of the service point.

If the utility is also the AHJ doing your inspections (like they are in two of the biggest PV markets in Texas), you won't get far with that approach.

 

[electrofelon]

If the utility is also the AHJ doing your inspections (like they are in two of the biggest PV markets in Texas), you won't get far with that approach.

The dreaded combo utility/AHJ! I dealt with one once: Tacoma WA.

 

[ggunn]

The dreaded combo utility/AHJ! I dealt with one once: Tacoma WA.

Precisely. Fortunately, we have a pretty good relationship with both of them. They both, however, have their ways of doing things and they are not the same. When in Rome...

 

[Carultch]

Square D HU361RB should be widely available. Or look up Industrial Controls Direct for European style plastic enclosure discos, if you don't actually need open blade.

Your utility seems kinda behind the times.

That Square D disconnect is only 600V rated. And you need to wire two poles in series to get the full 600V rating in DC.

 

[jaggedben]

That Square D disconnect is only 600V rated. And you need to wire two poles in series to get the full 600V rating in DC.

Yes, you're correct. I was going off the OP saying he thought he could get away with 600V. I didn't try to verify if that's correct.

Positive on one pole and negative on the other is two poles wired in series, btw.

 

[pv_n00b]

We have some 33kw inverters 480v. Ac and 1000v DC
Utility wants DC disconnects on the line side of inverter. Even tho inverters have DC disconnects.
So we usually just disconnect the positive side and negative straight to inverter.
Since positive I believe is 450 volts to ground we could get away with 600v disconnects.

If we need 1000v disconnects open blade what will you all use? And where to buy?
Thanks in advance

The voltage across the disconnect is up to 1,000V in that system so you need 1,000V rated equipment.

Eaton has 1,000V DC disconnects with visible blades. Order the box with the window option, opening a 1,000V disconnect to verify the blade position is not a safe option. The disconnect has to open all ungrounded conductors.

 

[pv_n00b]

If the utility is also the AHJ doing your inspections (like they are in two of the biggest PV markets in Texas), you won't get far with that approach.

Never run across that myself, but I do occasionally see utilities who are not the local building inspector try to slip in requirements on the customer's side. I guess as long as they are trained on the NEC who cares, but it sounds like these folks are going outside the NEC requirements. I always push back when this happens and usually win if I am polite but insistent about being show what in the NEC they are basing their requirement on.

 

[ggunn]

Never run across that myself, but I do occasionally see utilities who are not the local building inspector try to slip in requirements on the customer's side. I guess as long as they are trained on the NEC who cares, but it sounds like these folks are going outside the NEC requirements. I always push back when this happens and usually win if I am polite but insistent about being show what in the NEC they are basing their requirement on.

The AHJ not following code is a different issue, but interpretations of code sometimes differ, as the San Antonio and Austin POCOs do on some significant points, both of which are municipally owned utilities. From building PV systems to their specs to "you touch it, you fix it", in the main we do things as they direct or we fail inspection. I have challenged them on some points, and I have even prevailed a few times, but I choose my battles.