Grid tie PV with Generator back up/

[Sierrasparky]

What is the proper way to add a portable generator to a home with PV grid tie Don't want the PV back-feeding the genny. Someone said add a Normally closed relay on the PV tie to the main panel that opens when the Generator is run?

 

[ron]

We put the PV connection on the utility side of the transfer switch, so when the generator is connected, there is no connectivity to the utility or PV.

 

[Sierrasparky]

We put the PV connection on the utility side of the transfer switch, so when the generator is connected, there is no connectivity to the utility or PV.

That works of you are using a transfer switch, if a interlock device is use then ?

 

[Deltaforce]

That works of you are using a transfer switch, if a interlock device is use then ?

Also ok
Very popular
Normally close relay option unsafe not use.

 

[ron]

That works of you are using a transfer switch, if a interlock device is use then ?

Interlock is just a manual transfer switch. Same solution.

 

[Sierrasparky]

Also ok
Very popular

Are you saying ok to use a interlock device? If so how do you prevent a back-feed if the PV is fed through a back-feed breaker. In this instance I am not getting involved in changing how the PV feeds the house panel.

 

[Deltaforce]

Are you saying ok to use a interlock device? If so how do you prevent a back-feed if the PV is fed through a back-feed breaker. In this instance I am not getting involved in changing how the PV feeds the house panel.

Grid down, pv inverter shut down pv, no supply in pv breaker
Home owner switch off main breaker, pv breaker

 

[curt swartz]

If the interlock is in the service panel it will not work. The PV would still be tied to the generator unless it is manually switched off. Definitely don't want to depend on homeowner turning off PV.

 

[electrofelon]

Are you saying ok to use a interlock device? If so how do you prevent a back-feed if the PV is fed through a back-feed breaker. In this instance I am not getting involved in changing how the PV feeds the house panel.

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. If provided, I wonder if you could trigger the rapid shut down function somehow.

 

[ramsy]

That works of you are using a transfer switch, if a interlock device is use then ?

Got two inspected this year, using load-side interlock.

The portable generators void SolarEdge inverter warranty, so solar DC must be opened with main, at same time geny DC is closed.

AHJ's have no clue, not aware of inverter listing violation with generators, and never seen interlock listed for 3 switches.

Interlock OEM had to produce NRTL letter, but recalcitrant AHJ's stand firm, citing NEC 110.3(C) due to NTRL no longer certified.

Passing inspection requires proof that NRTL was certified at time test results were issued to interlock manufacturer (OEM).

Among 141 UL research documents, and correspondence related to certification status of NRTL in question, only 2 sentances provide relavant proof. It was a needle in the haystack, but I got the proof.

Orange County Public Works AHJ remained none responsive, until legal proof settled NRTL certification at specific dates indicated, and was provided to the Building Official at the State capital in Sacramento.

 

[Deltaforce]

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.

Interlock kit still needed

 

[Sierrasparky]

Got two inspected this year, using load-side interlock.

The portable generators void SolarEdge inverter warranty, so solar DC must be opened with main, at same time geny DC is closed.

AHJ's have no clue, not aware of inverter listing violation with generators, and never seen interlock listed for 3 switches.

Interlock OEM had to produce NRTL letter, but recalcitrant AHJ's stand firm, citing NEC 110.3(C) due to NTRL no longer certified.

Passing inspection requires proof that NRTL was certified at time test results were issued to interlock manufacturer (OEM).

Among 141 UL research documents, and correspondence related to certification status of NRTL in question, only 2 sentances provide relavant proof. It was a needle in the haystack, but I got the proof.

Orange County Public Works AHJ remained none responsive, until legal proof settled NRTL certification at specific dates indicated, and was provided to the Building Official at the State capital in Sacramento.

As others have stated and my concern. Listing or not what do you use to open load side PV back-feed with a portable genny and panel interlock device. Unless you we referring to line side PV tap.

 

[electrofelon]

Interlock kit still needed

I which situation? Also please provide code reference.

 

[Deltaforce]

I which situation? Also please provide code reference.

Nothing prevent accidental parallel of utility and genny in such situations. 702 provide ssfeguard

 

[electrofelon]

Nothing prevent accidental parallel of utility and genny in such situations. 702 provide ssfeguard

Although a good idea, I dont think you will find a code article requiring the PV input be mechanically interlocked. Perhaps one could cite 702.5 and claim the PV is a "normal source", but think about it, some sources could be intended to operate in parallel with a generator so there cant be a blanket prohibition against it.

 

[ggunn]

Are you saying ok to use a interlock device? If so how do you prevent a back-feed if the PV is fed through a back-feed breaker. In this instance I am not getting involved in changing how the PV feeds the house panel.

With "normal" equipment you will have to move the PV connection point out of the panel to the line side or, as some have suggested, install normally open contactors in the PV feed with sensors connected to the line side of the main breaker. The generator must not operate in parallel with either the grid or the PV system. I agree that contactors are a bit risky; if the grid goes down and the contactors fail to disconnect the PV, it could be bad news for the generator.

 

[Deltaforce]

Although a good idea, I dont think you will find a code article requiring the PV input be mechanically interlocked. Perhaps one could cite 702.5 and claim the PV is a "normal source", but think about it, some sources could be intended to operate in parallel with a generator so there cant be a blanket prohibition against it.

You say interlock not required if this complied?:
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.

 

[electrofelon]

You say interlock not required if this complied?:
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.

I am saying i don't see any code requiring a mechanical interlock on a PV system, ever, even if its load side connected.

 

[ggunn]

I am saying i don't see any code requiring a mechanical interlock on a PV system, ever, even if its load side connected.

But of course and as we all know, not everything that is permitted through omission by the NEC is a good idea.

 

[Deltaforce]

I am saying i don't see any code requiring a mechanical interlock on a PV system, ever, even if its load side connected.

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