PV array for an individual apartment

[Grouch1980]

Hey guys,
We're renovating a penthouse apartment on the 17th floor of a building. The tenant wants to add a solar PV array that will serve their apartment only. The building has maybe 30 or 40 apartments.

We'll connect the inverter to a breaker on the panel inside the apartment. I'm assuming there's no violation with this? The meter for this apartment would have to be a bi-directional meter.

Thanks!

 

[jaggedben]

No violation.

Hopefully the utility doesn't want a disconnect on the ground floor.

 

[pv_n00b]

There's going to be a meter room and each meter will have a circuit breaker. With this many meters, there will be a main service disconnect. So you are doing a load side interconnection and you will need to review all the electrical equipment between the apartment panel and the service disconnect. As Jaggedben brought up, you need to know before you start if the AHJ will require a PV disconnect in the meter room. It might not be possible to install one. Better to know upfront.

 

[ggunn]

Hey guys,
We're renovating a penthouse apartment on the 17th floor of a building. The tenant wants to add a solar PV array that will serve their apartment only. The building has maybe 30 or 40 apartments.

We'll connect the inverter to a breaker on the panel inside the apartment. I'm assuming there's no violation with this? The meter for this apartment would have to be a bi-directional meter.

Thanks!

Do the apartments all have their own services, separately metered with service conductors connected to disconnects and meters at the units, or is there a meter bank at ground level? Is the building owner OK with the penthouse occupant commandeering space on the roof for their exclusive benefit?

Most apartment service panels are pretty small; if you backfeed a breaker you can only connect a PV system with inverter max output of 16% of the panel rating, assuming that the OCPD is the same as the panel rating, and as jaggedben points out, most utilities want to see a readily accessible PV system disconnect at ground level.

I do not see any code violations on the face of what you posted, but there will likely be challenges.

 

[Grouch1980]

Thanks all. There is a meter bank in the cellar. However, the renovation of the apartment will require an upgrade, and so we are considering breaking out the apartment from that meter bank... installing a stand-alone meter and fused switch adjacent to the existing meter bank, and running a new feeder to the apartment.

I'm confused about the potential PV disconnect; where does it have to be located? Am I only disconnecting the new feeder to the apartment?

 

[jaggedben]

The NEC would not require a bladed PV disconnect or any additional disconnect other than a breaker in the unit panel. However some utilities do have such requirements. They would apply to the PV output circuit, not the unit feeder.

You should use an inverter type (e.g. microinverters) where shutting down the AC power initiates rapid shutdown. Since your building is bigger than a two family dwelling, that switch does not need to be outside. So really, it's just as above: Assuming the building department follows the NEC or equivalent, it's the utility requirements you need to inquire about.

 

[Grouch1980]

The NEC would not require a bladed PV disconnect or any additional disconnect other than a breaker in the unit panel. However some utilities do have such requirements. They would apply to the PV output circuit, not the unit feeder.

Understood.

You should use an inverter type (e.g. microinverters) where shutting down the AC power initiates rapid shutdown. Since your building is bigger than a two family dwelling, that switch does not need to be outside. So really, it's just as above: Assuming the building department follows the NEC or equivalent, it's the utility requirements you need to inquire about.

Someone else will be designing the PV system. So this PV disconnect being mentioned above in the meter room is for rapid shutdown? If I remember correctly, NYC doesn't require rapid shutdown since we're still on the 2008 NEC. If that's the case, then we don't need this PV disconnect?

 

[jaggedben]

If loss of AC power initiates rapid shutdown, (as it does on most inverters used for small systems nowadays), then no additonal disconnect is needed per the NEC if it's not in a one or two family dwelling. (On a one or two family dwelling there must be a switch outside the building to initiate rapid shutdown, but it could be the service or feeder or PV breaker. So an additonal disconnect would only be required if all those were inside.) But yes, this all moot if you're on the 2008 code.

I don't know why a building department would require a PV circuit disconnect in the meter room if following any version or cycle of the NEC. But again, the utility might. Some people use 'AHJ' for both those entities.