Unplugging DC connectors under load from micro-inverter

[Zee]

What would happen if you unplugged a 60 cell panel (~40V Voc) in sunshine and under load from a micro-inverter?
Also, if you unplugged the micro from the AC trunk cable?

 

[GoldDigger]

What would happen if you unplugged a 60 cell panel (~40V Voc) in sunshine and under load from a micro-inverter?
Also, if you unplugged the micro from the AC trunk cable?

If you unplugged a DC connector, which is not designed to be load breaking, there would be an arc as the connector separated which could startle you and potentially damage the connector so that it no longer operated correctly when reconnected.
This is more of a problem with the higher DC voltages found with a string inverter, but it is still possible even with 40V DC.

The AC connector, OTOH, will be protected because the current naturally goes through zero, putting much less stress on the connector as it is separating. I do not know whether it is officially rated for load breaking though.
Once you have unplugged the AC connector, the DC draw will be stopped and you can then safely disconnect the DC. The terminals on the panel side will still have 40V across them, so do not be casual with them.

 

[jaggedben]

I'd be surprised if the AC connector isn't load break rated (per 690.33). Ask the manufacturer if you want to be sure. But you probably unplug things from wall outlets all the time which have much more load connected.

 

[Zee]

you probably unplug things from wall outlets all the time which have much more load connected.

good point

 

[Zee]

Right. On higher V DC systems, I would never willingly unplug an MC connector.

I was just wondering what arc forms at 40 VDC.

I like your point on unplugging AC...then DC flow stops. Excellent idea.... or at least preferable to DC unplugging!
Thing is to have that funky orange plastic tool handy!:dunce:

 

[ggunn]

I'd be surprised if the AC connector isn't load break rated (per 690.33). Ask the manufacturer if you want to be sure. But you probably unplug things from wall outlets all the time which have much more load connected.

The AC output connectors from microinverters are usually (always?) load break rated; that way they qualify as an inverter disconnecting means per 690.15(A)(2).