PV disconnect labeling

Superhawk

New User
Location
NJ
Occupation
Engineer
We have an inspector having an issue with a load side AC disconnect. He is suggesting the disconnect is not suitable for backfeeding because the disconnect has internal etchings for load/line. I know the requirement applies to CBs but I never seen it applied to disconnect switches. Actually i havent seen a disco without such markings from the manufacturer. Also I couldnt find anything in the code that would suggest a label could supersede factory etchings.

1. Are disconnects available without those markings?
2. is there any issue with a disconnect potentially loaded from both ends? if not, is there a code reference that would allow a label to supersede factory etchings?

thanks for any feedback!
 

Carultch

Senior Member
Location
Massachusetts
There is no issue with feeding power the opposite direction through a disconnect, fused or unfused. It is just a blade and (if fused) a meltable element that can carry a mix of current and voltage either direction. Disconnects are intrinsically bi-directional, in terms of which way power can flow.

The reason for the line/load markings, which are important, is to identify the wiring orientation for the terminals that remain energized after the unit is shut off. The disconnect is built so it can de-energize as much of the unit as possible. The fuses, the load terminals, the open blades, are all de-energized. Some disconnects even have a plastic shield over the line-side terminals, to improve the safety for people servicing the disconnect. Some also have a small hole in this shield on each phase to fit volt meter probes to the line side terminals.

The load side terminals should always point toward the inverter, whether on the AC or DC side.
 

jaggedben

Senior Member
You are using the disconnect according to its listing, as Carultch explains. And there is no requirement in the code or anywhere else that requires switches to be suitable for backfeeding. They are inherently so.
 
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