AC disconnect used as a junction box?

[jayzbond007]

Hi,
I have a solar array on top of a residence. The city requires a roof top ac disconnect. The array usually have a junction box to make all the splice connections then go into a ac disconnect. Is it possible to avoid the junction box and make all the splice connections in the ac disconnect? I have seen installations where they do this, but not sure if this is allowed by code.

The system I am designing on the roof is enphase microinverters.

Any feedback is greatly appreciated.

Thanks,

Jason

 

[ggunn]

Hi,
I have a solar array on top of a residence. The city requires a roof top ac disconnect. The array usually have a junction box to make all the splice connections then go into a ac disconnect. Is it possible to avoid the junction box and make all the splice connections in the ac disconnect? I have seen installations where they do this, but not sure if this is allowed by code.

The system I am designing on the roof is enphase microinverters.

Any feedback is greatly appreciated.

Thanks,

Jason

Why do they want an AC disco on the roof? It's not that "output circuit" misunderstanding again, is it?

I don't believe you can put splices inside a disco and maintain its UL listing.

 

[jaggedben]

What we do is put in a 240V rated 2-pole lightswitch and an outdoor rated cover. Yes, you can actually do this.

Why do they want an AC disco on the roof? It's not that "output circuit" misunderstanding again, is it?

One of the AHJs we work with requires this because the AC plug on the Enphase trunk cable requires a tool. For this reason they won't accept that plug as the disconnect required by 690.14(D)(2).

I don't believe you can put splices inside a disco and maintain its UL listing.

Really? Anyway we use a bell box that is certainly listed for that.

 

[iwire]

I don't believe you can put splices inside a disco and maintain its UL listing.

Sure you can, see 404.3(B) but read the entire section, not just the first sentence.

 

[ggunn]

Sure you can, see 404.3(B) but read the entire section, not just the first sentence.

Cool. I stand corrected and the master electrician who told me that will also stand corrected should I ever see him again.

 

[jayzbond007]

AC disconnect used as a junction box?

The city of San Diego, for example, has a requirement for all homes in their jurisdiction that any solar arrays with microinverters will need a rooftop ac disconnect at each branch circuit. If there was a fire or emergencies, local authorities can shut the power off. I'm sure if they were smart, they will just shut the power off at the main service panel.

 

[ggunn]

The city of San Diego, for example, has a requirement for all homes in their jurisdiction that any solar arrays with microinverters will need a rooftop ac disconnect at each branch circuit. If there was a fire or emergencies, local authorities can shut the power off. I'm sure if they were smart, they will just shut the power off at the main service panel.

This shows a lack of understanding by the city of how solar works. As you say, firefighters can just shut down the MSP (which they do, anyway) and all the microinverters will shut down. This is one of the selling points of microinverters, that when you shut off the interconnection all the conductors except the jumpers between the modules and their respective inverters are de-energized. AC discos on the roof are unnecessary.

 

[jaggedben]

The city of San Diego, for example, has a requirement for all homes in their jurisdiction that any solar arrays with microinverters will need a rooftop ac disconnect at each branch circuit. If there was a fire or emergencies, local authorities can shut the power off. I'm sure if they were smart, they will just shut the power off at the main service panel.

Sad.