Rooftop Disconnect Switch for Solar Panels?

[Mark5555]

I have 2 strings containing ten 395 watt panels each. I understand the proper practice is to have a disconnect switch inside of my 2 rooftop EZ Solar JB 1.2 junction boxes. Each array is 366V, 13.8A, and 3,950W. The inverter has a disconnect and there is a DC breaker box with fuses, arresters and breakers all in the garage, but I read somewhere that it's a good idea to have a disconnect switch (not a breaker) up near the panels when doing maintenance. So if I were to put one inside of the JB's, can anyone recommend a reasonably priced one to handle a single string (red/black wires)?

 

[zanydroid]

I don’t have one to recommend, but I would bet most votes will come down against adding disconnect in the roof, since it’s an extra point of failure in hot environment.

Putting disconnect inside an EZ solar would additionally involve removing a dead front , reducing safety, to access a disconnect that ostensibly is there to increase safety.

And did you read quality content from recent sources? Things do change quite a lot in solar.

 

[peakbagger]

Soladecks have a din rail inside and space for fused disconnects.

 

[zanydroid]

Soladecks have a din rail inside and space for fused disconnects.

EZ solar are like smaller plastic soladecks, so they’re isomorphic in that sense.

 

[Gold Country Russ]

The newest version of the NEC and California demand remotely actuated "rapid shutdown" on all new rooftop PV installations. It doesn't apply to ground mounts though. It's a fire/fireman safety issue. Rapid shutdown should not be confused with a PV disconnect switch or circuit breaker and it demands a properly labeled E-stop switch.

 

[Gold Country Russ]

Continued: Some of the newer inverters are equipped with this feature but the external parts are not included. I know the EP Cube I just bought will have a "TIGO Rapid Shutdown" installed it the gateway. My application will not use it though. Not sure how big an issue this will be on micro inverter users though.

 

[DIYrich]

IMO DC Disconnect Rooftop Isolator Switch

IEC 60364-7-712, dc disconnect, imo, ul listed, DC AC, DC DISC

signaturesolar.com

 

[mciholas]

The newest version of the NEC and California demand remotely actuated "rapid shutdown" on all new rooftop PV installations. It doesn't apply to ground mounts though. It's a fire/fireman safety issue.

I don't think it is, actually. It is a manipulation of the code to increase sales of microinverters and MLPE.

Studies showed firefighters are not seriously at risk from a PV array.

This covers the issue reasonably well:

Years ago, no RSD was required. Then it was when pushed by companies like Tigo and Enphase. Studies show this really isn't necessary, so now code allows UL 3741 which allows not using RSD, but the code writers made it cumbersome to get approved and required system level approvals.

Money spent on RSD is wasted, but code requires it in most cases.

Mike C.

 

[Gold Country Russ]

I don't think it is, actually. It is a manipulation of the code to increase sales of microinverters and MLPE.

Studies showed firefighters are not seriously at risk from a PV array.

This covers the issue reasonably well:

Years ago, no RSD was required. Then it was when pushed by companies like Tigo and Enphase. Studies show this really isn't necessary, so now code allows UL 3741 which allows not using RSD, but the code writers made it cumbersome to get approved and required system level approvals.

Money spent on RSD is wasted, but code requires it in most cases.

Mike C.

For those of us in the former Paradise known as California, it is not negotiable for a new rooftop solar PV permit. My fellow citizens haven't been able to get their voting right since Reagan, so there is little common sense in government here. I don't know about other states though. I was doing a big project in Concord, NC and was shocked that they were just as bad or maybe even worse.

 

[Osmethne]

I don't think it is, actually. It is a manipulation of the code to increase sales of microinverters and MLPE.

Studies showed firefighters are not seriously at risk from a PV array.

This covers the issue reasonably well:

Years ago, no RSD was required. Then it was when pushed by companies like Tigo and Enphase. Studies show this really isn't necessary, so now code allows UL 3741 which allows not using RSD, but the code writers made it cumbersome to get approved and required system level approvals.

Money spent on RSD is wasted, but code requires it in most cases.

Mike C.

I knew it! I knew those RSD requirements were completely stupid and ill founded this entire time. I'm glad to see this is finally being acknowledged.