2011 NEC 690.35

[ptrombley]

Does 690.35 require that both the + and - DC conductors (in an ungrounded system) are fused and/or disconnected at EACH point where fusing or disconnecting means are provided?
In other words- if I have six strings and coming into a DC combiner on the roof and my inverter (at another location) disconnects both the + and - conductors, do I still need to disconnect both the + and - conductors in my DC combiners on the roof?

 

[shortcircuit2]

My reply would be anywhere fuses or disconnects are REQUIRED...you must fuse or disconnect both ungrounded conductors of the system.

 

[SolarPro]

Yes. That's the down side of ungrounded PV system: twice as many fuses and disconnect poles.

Here's an extended meditation on the subject of Ungrounded PV Power Systems in the NEC.