DC Disconnect Location.

verdigo

Doing a bit of wiring and was wondering what the NEC's reg was for locating a DC disconnect inside or outside. I would be using a PV combiner box as the disconnect.

Thanks

Dennis

Vic

Re: DC Disconnect Location.

Hi Dennis,

Just speaking about convenience, and NOT NEC;

The MidNite Classic will want a DC breaker on its output lead to the batteries. It is always best to remove the PV input to the Classic before removing the Output connection, and to apply the output first and the PV in last. It is convenient to have those two breakers close to the Classic, for possible immediate intervention if needed, and switching the output breaker on the Classic is needed for every Firmware Update.

Depending on the NEC version in use there (if inspection is needed) the answers vary, and so on.

Have fun with the system, Vic

verdigo

Re: DC Disconnect Location.

Thanks for the reply Vic. I have a couple of new Midnite E-Panels that I bought off E bay. I believe they have the two breakers your speaking of pre-installed. I haven't opened them up yet because they are built for Outback inverters, and they have the doors hinged on the wrong side for use with a single Outback inverter and Classic CC. I still haven't settled on a particular inverter yet. Anyway they were dirt cheap and I felt I could use one even if I had to modify its intended use, but haven't opened them as I might re-sell them. My concern is whether or not the NEC requires an outside central DC disconnect for emergency personnel ect.

Dennis

inetdog

Re: DC Disconnect Location.

verdigo wrote: »

My concern is whether or not the NEC requires an outside central DC disconnect for emergency personnel ect.

Dennis

It requires a disconnect in sight of the panels for maintenance purposes, and it requires a disconnect before the DC wiring enters the building UNLESS it is run in conduit directly to a disconnect at the inverter.
Local regulations may require an accessible disconnect at the service entrance or before the wiring enters the house, but if so that is beyond what the NEC requires.

Caution: When you say "the NEC" you really need to specify the year (code cycle) since different jurisdictions are faster or slower in adopting NEC changes.
For example, the allowance for putting the main DC disconnect at the inverter was not in the NEC before the provisions for PV were updated. Not sure of which year it was changed.
2014 NEC will be more strict about emergency disconnects though.

verdigo

Re: DC Disconnect Location.

Probably better safe than sorry.

westbranch

Re: DC Disconnect Location.

AS you will see when you open the E-panels up, they are mirrored on each side, ie you can 'flip' the layout to the other side as described in the manual, with a bit of do-it-yourself effort. note: the factory installed screws are in very 'tight'...