Plug in solar and GFIs

[pv_n00b]

UL has published a good white paper on this subject, Safety Considerations for Plug-In Photovoltaic (PIPV) Systems. I recommend reading it to understand some of the issues. It points out the problems with GFCI circuits.

Safety Considerations for Plug-In Photovoltaic (PIPV) Systems

Understand the unique risks of plug-in photovoltaic (PIPV) systems and key safety considerations for residential use in this white paper.

www.ul.com

 

[wwhitney]

It points out the problems with GFCI circuits.

The most interesting point to me was that GFCI receptacles disconnect both circuit conductors when they trip, while GFCI breakers don't disconnect the neutral conductor (although obviously they could have been designed to do so).

So if you have a ground fault with PIPV on the load side of a GFCI receptacle, when the receptacle trips, the neutral current path is cut off and the PIPV can no longer supply power to the ground fault. While if the branch circuit is protected by a GFCI breaker, the PIPV can continue to provide current to the ground fault until its anti-islanding feature detects the loss of the grid. The UL standard for that allows up to 2 seconds to disconnect.

Cheers, Wayne

 

[jim dungar]

The most interesting point to me was that GFCI receptacles disconnect both circuit conductors when they trip, while GFCI breakers don't disconnect the neutral conductor (although obviously they could have been designed to do so).

Probably because you cannot misfire a GFCI breaker by swapping Line and Load connection as you can with a feed thru receptacle.

Opening the receptacle neutral is a relatively recent requirement, considering GFCIs were introduced more then 50 years ago.