DC Disconnect for 4 sub-arrays

[robomartin]

Midget DC fuses come in both 600V and 1000V sizes in a good range of amps. I have used both. I have never blown a DC fuse while disconnecting....of course I have never tried to disconnect under load.

Even the string inverter manufacturers recommend to not operate their built in DC switches under load. But then again what makes sense and common practice among electricians is completely oblivious to the general public. Then again the general public gets to pay the repair bills.

Silly question: What do you do if you need to DC disconnect the array in a non-emergency situation? Wait 'till night time and work on it at night?

[bcroe]

Silly question: What do you do if you need to DC disconnect the array in a non-emergency
situation? Wait 'till night time and work on it at night?

Certainly work at night. I have several outdoor GFI outlets mounted on my ground mounted
panels; just plug in some lights and tools. Protects me and the equipment. Bruce Roe

[DanS26]

Silly question: What do you do if you need to DC disconnect the array in a non-emergency situation? Wait 'till night time and work on it at night?

You open the AC disconnect. That process shuts down your string inverter. Then you open the DC switch on the string inverter. Now the load is removed from your array. Next step is to open your DC fuses in the disconnect at the array. Now disconnect your panels from its string and then they can be removed or repaired.

Reverse the the process to reenergize the system.

[DanS26]

I think this article could help clear up terminology in this thread and many other threads on this forum. It is sometimes difficult when individuals refer to a disconnector, a switch or a circuit breaker.

Hopes this helps:

http://electrical-engineering-portal...connectors-cbs

[robomartin]

I've ended-up going with four individual 3-pole disconnects. Square-D HU361RB all four. I'm running out of time if I am going to pull this off by year end. I know LA County likes these so I'll just throw money at it at this point.

Thanks for all the input.

[DanS26]

Wow! $130 apiece for those switches.....a $520 expenditure. But I understand why you had to do it....time is money. Hope it turned out well.