GFCI and an Open Ground
Given: A 120 VAC GFCI supplying power to a 30 AMP RV. The RV has one problem, the 3rd Prong Ground wire at the 30 AMP plug is not making connection. (The RV chassis is floating because there are no ot...
Forum Discussion
myredracer wrote:It's best for any of these GFCI info sources to not make broad specific statements on how the grounded neutral detection works. Better to present things as an example of how it can be done. As wnjj pointed out after digging into spec sheets, in at least a couple of the implementations the 2nd coil does not do any detecting, and the separate transformer has given way to an added coil on the current detecting transformer. Maybe there are one or more cases where the 2nd coil really does detect, so I'm trying to be cautious. Continuing the trend, I just found a chip that needs only a single coil winding for everything. I didn't see any explanation of how this one works. http://www.icbase.com/File/PDF/ONS/ONS54501409.pdf
Here's a couple of diagrams that show how the 2nd coil detects a grounded neutral current flow.
I think what's behind all the downstream grounded neutral debate is that when somebody diligently goes to the web to see how a GFCI works, they have a 90+% chance of pulling up an explanation that totally omits that grounded neutral detection even exists. And for the <10% that learn that it exists, they'll be led to believe that there's exactly one way that it's done, which is the trap I fell in to.
