Grid tie PV with Generator back up/

Deltaforce said:
Need of nterlock for genny in situations of

IF you have a backfed breaker and want to make it idiot proof, you either have to change it to a supply side connection or put some sort contactor on the inverter output circuit.

702.6 mandate transfer equipment, interlock included
Click to expand...
FWIW, I am pretty sure that electrofelon knows all that.
 
Deltaforce said:
Need of nterlock for genny in situations of

IF you have a backfed breaker and want to make it idiot proof, you either have to change it to a supply side connection or put some sort contactor on the inverter output circuit.

702.6 mandate transfer equipment, interlock included
Click to expand...
I am having a hard time understanding what you are saying. I do not believe there is a code requirement to mechanically interlock out the inverter. Whether it is a good idea is another story.

Personally I would be fine with a contactor to drop out the inverter, and not have a mechanical interlock.
 
electrofelon said:
I am having a hard time understanding what you are saying. I do not believe there is a code requirement to mechanically interlock out the inverter. Whether it is a good idea is another story.

Personally I would be fine with a contactor to drop out the inverter, and not have a mechanical interlock.
Click to expand...
Thanks your forbearance
No interlocking of inverter
Interlocking of standby generator with utility
702.6 talks about that
For your 'Personally I would be fine with a contactor to drop out the inverter, and not have a mechanical interlock', it prevent parallel of standby generator and pv.
But it does not prevent parallel of standby generator and utility
For that interlocking of main breaker and standby generator required as per 702.6
 
Deltaforce said:
Thanks your forbearance
No interlocking of inverter
Interlocking of standby generator with utility
702.6 talks about that
For your 'Personally I would be fine with a contactor to drop out the inverter, and not have a mechanical interlock', it prevent parallel of standby generator and pv.
But it does not prevent parallel of standby generator and utility
For that interlocking of main breaker and standby generator required as per 702.6
Click to expand...
He isn't talking about not having an interlock separating the generator from the utility, just a means to prevent the PV system from connecting to the generator. Move the PV point of interconnection to the supply side, install an interlock on the main panel, and be done with it. Supply side PV interconnections are not difficult.
 
I was thinking of using a normally closed relay that opens if the generator has energized the back-feed breaker.
 
Deltaforce said:
But complex, approval utility side need etc
Click to expand...
Are you new to solar? Those of us who aren't do them all the time. They are not at all complex, and as for utility approval, you don't need special approval to do a 705.11 interconnection unless the POCO expressly denies them. Do your homework; look at their interconnection guidelines or make a phone call or two.

I have had very few encounters with POCOs for whom supply side PV interconnections are a concern. You have to do something to keep the generator separated from the PV, and every alternative we have discussed, not that there are many of them, are more complex than a supply side PV interconnection.
 
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ggunn said:
Are you new to solar? Those of us who aren't do them all the time. They are not at all complex, and as for utility approval, you don't need special approval to do a 705.11 interconnection unless the POCO expressly denies them. Do your homework; look at their interconnection guidelines or make a phone call or two.

I have had very few encounters with POCOs for whom supply side PV interconnections are a concern. You have to do something to keep the generator separated from the PV, and every alternative we have discussed, not that there are many of them, are more complex than a supply side PV interconnection.
Click to expand...
ggunn said:
Are you new to solar? Those of us who aren't do them all the time. They are not at all complex, and as for utility approval, you don't need special approval to do a 705.11 interconnection unless the POCO expressly denies them. Do your homework; look at their interconnection guidelines or make a phone call or two.

I have had very few encounters with POCOs for whom supply side PV interconnections are a concern. You have to do something to keep the generator separated from the PV, and every alternative we have discussed, not that there are many of them, are more complex than a supply side PV interconnection.
Click to expand...
Hard to believe it default way of doing
As more complex, more expensive
Make it last option when service panel too small to add pv breaker nec 120% rule
 
Deltaforce said:
Hard to believe it default way of doing
As more complex, more expensive
Make it last option when service panel too small to add pv breaker nec 120% rule
Click to expand...
You can believe it or not, but moving the PV to a supply side connection is a very common way to protect a generator when it comes in as a retrofit after PV is already installed on the load side. It's as simple as adding a fused disconnect and a tap to the service conductors; any experienced electrician can do it very easily. It's a little more expensive than just landing a PV breaker but not compared to the cost of a generator, and your customer should have had this explained to him before he bought the generator because he cannot leave the PV connected the way it is.

As we have told you repeatedly, you have to do something to protect the generator from backfeed from the PV system. You can move the PV to the supply side or you can add series contactors to the PV conductors. Either way there will be associated costs and complexity, and either way you will have to get access to the service conductors.

Your last assertion is a whole 'nother can of worms, but when the PV system cannot connect in the main panel because of 705.12 concerns you have just three options: move the PV connection to the supply side, downgrade the main breaker to make electrical room for the PV, or reduce the size of the PV system to fit. The third option is the most unlikely to appeal to a customer, but in my experience the other two are about equally used in residential settings.
 
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ggunn said:
You can believe it or not, but moving the PV to a supply side connection is a very common way to protect a generator when it comes in as a retrofit after PV is already installed on the load side. It's as simple as adding a fused disconnect and a tap to the service conductors; any experienced electrician can do it very easily. It's a little more expensive than just landing a PV breaker but not compared to the cost of a generator, and your customer should have had this explained to him before he bought the generator because he cannot leave the PV connected the way it is.

As we have told you repeatedly, you have to do something to protect the generator from backfeed from the PV system. You can move the PV to the supply side or you can add series contactors to the PV conductors. Either way there will be associated costs and complexity, and either way you will have to get access to the service conductors.

Your last assertion is a whole 'nother can of worms, but when the PV system cannot connect in the main panel because of 705.12 concerns you have just three options: move the PV connection to the supply side, downgrade the main breaker to make electrical room for the PV, or reduce the size of the PV system to fit. The third option is the most unlikely to appeal to a customer, but in my experience the other two are about equally used in residential settings.
Click to expand...
I just noticed that you are in India; the rules may very well be different there. Does India enforce the US NEC? Protecting the generator from backfeed from a PV system is physics rather than code, though.
 
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