Shedding Loads

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BayElectric

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Hello,

Seeking input if anyone familiar with any requirements in the code for backup power such as PV batteries or generator for shedding loads.
The only relating thing I find is 710.15, but this only refers to single load rather than the entire load center being fed by the transfer switch.

Thanks,
 
In my reading the difference between 710 and 702 is that 710 would apply to a PV/battery system that never connects to the grid, whereas 702 would apply to a system that normally is connected to the grid but operates as a standby generator in an outage. That said I've seen a lot of people try to apply only 710.15 to systems that are normally grid-tied.

Perhaps one might argue about which to apply differently for an 'AC coupled' backup system in which the battery inverter is not directly connected to the DC output of solar panels.

It's a little unclear what kind of system you're asking about, although your phrasing seems to refer to a normally grid-connected system.
 
jaggedben said:
In my reading the difference between 710 and 702 is that 710 would apply to a PV/battery system that never connects to the grid, whereas 702 would apply to a system that normally is connected to the grid but operates as a standby generator in an outage. That said I've seen a lot of people try to apply only 710.15 to systems that are normally grid-tied.

Perhaps one might argue about which to apply differently for an 'AC coupled' backup system in which the battery inverter is not directly connected to the DC output of solar panels.

It's a little unclear what kind of system you're asking about, although your phrasing seems to refer to a normally grid-connected system.
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my problem is that 702 is for stand-by systems. Solar systems, by definition, aren't in standby mode at any time. They falls under 705, as parallel power source in standard operation and 710, stand-alone when grid power goes out.
All solar installations that I've seen in the past couple years, are all using batteries with built in inverters. There's hardly any DC in these systems other than the panels themselves. The batteries aren't stand-by either, they are being charged during the day and depleted during night time.

My main concern is that the only requirement for complete solar system (including batteries) is to meet 710.15 for single load, rather than have some type of load management although all solar systems have a built in transfer switch, in their gateway, to disconnect from the grid in case of power outage which is covered in 702 for standby systems.
 
The scope of 710 includes 'power production sources operating in stand-alone mode' so it applies to battery and solar/battery systems capable of operating that way. 705 is not relevant to your question. There is no logic in saying that 710 or 702 don't apply just because 705 also may apply. Solar systems are not by definition 'not standby'. Some are, some aren't.

Battery and solar/battery systems are not excluded from the scope and definitions in 702 as far as I've noticed. If you feel a need to apply 702 to a situation involving those systems, I don't see what's stopping you or what the 'problem' is.
 
jaggedben said:
The scope of 710 includes 'power production sources operating in stand-alone mode' so it applies to battery and solar/battery systems capable of operating that way. 705 is not relevant to your question. There is no logic in saying that 710 or 702 don't apply just because 705 also may apply. Solar systems are not by definition 'not standby'. Some are, some aren't.

Battery and solar/battery systems are not excluded from the scope and definitions in 702 as far as I've noticed. If you feel a need to apply 702 to a situation involving those systems, I don't see what's stopping you or what the 'problem' is.
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My problem is that 690 specifically refers to 710 which does not make much sense in today's systems. It should require load management specifically for A/C systems with cold start that my try to start on batteries without enough power.
 
BayElectric said:
My problem is that 690 specifically refers to 710 which does not make much sense in today's systems. It should require load management specifically for A/C systems with cold start that my try to start on batteries without enough power.
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If the A/C starting current is too large for the battery then I think 710.15 prohibits backing it up. Whether you do that with load management devices or by just not putting it on a backed up panel I think the requirement is met. And again, you can apply 702 if you want.

I can see how the code could be better organized but I'm still not sure what the 'problem' is.
 
jaggedben said:
If the A/C starting current is too large for the battery then I think 710.15 prohibits backing it up. Whether you do that with load management devices or by just not putting it on a backed up panel I think the requirement is met. And again, you can apply 702 if you want.
jaggedben said:
If the A/C starting current is too large for the battery then I think 710.15 prohibits backing it up. Whether you do that with load management devices or by just not putting it on a backed up panel I think the requirement is met. And again, you can apply 702 if you want.

I can see how the code could be better organized but I'm still not sure what the 'problem' is.
Click to expand...

I can see how the code could be better organized but I'm still not sure what the 'problem' is.
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What if the A/C current by itself meets the criteria of 710.15, but with additional loads, batteries will not have enough power for cold start? Article 710 does not take it under consideration.
Using article 702 for solar, is an non ending argument as PV systems don't operate under standby conditions.
 
BayElectric said:
What if the A/C current by itself meets the criteria of 710.15, but with additional loads, batteries will not have enough power for cold start? Article 710 does not take it under consideration.
Using article 702 for solar, is an non ending argument as PV systems don't operate under standby conditions.
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PV and battery systems DO operate under standby conditions in some circumstances. I think there's nothing in 702 that stops you from applying it to PV+Battery systems that meet the scope and definitions of that article.
 
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