PV - AC Disconnect at Utility Point of Connection

[BearState]

A couple of question as follows with regards to the PV System AC disconnect:

1. Is it required to have an AC diconnect switch after the Inverter Unit?

2. Is the AC disconnect connected to the Utility Main Swbd allowed to be located outside in a different room? Is it allowed to be located in a different floor? What are the requirements that will allow us to install in a remote location?

Thanks in advance.

 

[jaggedben]

A couple of question as follows with regards to the PV System AC disconnect:

1. Is it required to have an AC diconnect switch after the Inverter Unit?

The NEC requires overcurrent protection and a disconnecting means, but this can be a circuit breaker in a panelboard.

Local jurisdictions or the utility may require an AC disconnect accessible from outside the building or property. Sometimes a circuit breaker in an outside load center will suffice, sometimes not. You'll have to ask them what they require.

2. Is the AC disconnect connected to the Utility Main Swbd allowed to be located outside in a different room? Is it allowed to be located in a different floor?

Distance or separation from the inverter are not mentioned in the NEC (at least not in 2011, and I don't recall anything from previous codes). The only clear cut requirements in the 2011 NEC that concern your questions are that the disconnect be readily accessible (705.22), and that inverters mounted in locations that are not readily accessible have an additional AC disconnect within sight of the inverter (690.14(D)). But again, local requirements may be more involved.

 

[BearState]

Thanks JaggedBen...if there's no distance requirement for the AC disconnect, can we then install one AC Disconnect between the Inverter and the AC Main Service Swbd? What if they are in two separate room/floor within the same building?

 

[jaggedben]

I'm assuming you are connecting to a breaker in the main switchboard. If so, check with your local agencies to see if an additional disconnect is even required. If it is, it can be in another room/floor. In fact, that may even be required for it to be readily accessible.

If you are not connecting to a breaker in the main switchboard then other considerations may come into play. Such as the tap rules, for example.

 

[wyrepullr]

Example of local requirement

Example of local requirement

In New Jersey, most POCO's require AC disconnect within sight of the meter. Although not NEC this is an example of a local requirement

 

[iwire]

Local jurisdictions or the utility may require an AC disconnect accessible from outside the building or property. Sometimes a circuit breaker in an outside load center will suffice, sometimes not. You'll have to ask them what they require.

Absolutely, check into this with the local utility.

Where I am the local utility requires a means of disconnect near the point of entrance that has a 'visible break' which rules out circuit breakers.

 

[BearState]

Thanks for your reply guys, anyway we are actually tapping directly into the bus of the Main Service the only disconnect switch is 60'-0" away next to the Inverter. This is not a done deal yet, I am still debating with the electricians that although NEC does not specify the location. I still prefer to have an additional Disconnect Switch at least as close as possible to the Main Switchboard. But somehow have to prove my case with the client. Thanks again.