SSR Leaking Current to Ground?

[dcarter]

I have the JLD612, and originally used it with the internal relay switching my heaters. All was fine, but I was limited in the wattage I could use. So this week I ordered & received one of your SSRs (by the way, kudos on the extremely quick shipping!). The only thing changed was to insert the SSR into the circuit (disconnected the internal relay contacts & connected the same wires to the output side of the SSR, connected SSR outputs of JLD612 to the DC inputs on the SSR). I haven't increased the wattage of the heaters yet, just wanted to make sure the basic SSR setup functioned correctly.

All is well until the "out" light on the JLD612 goes on & the SSR is activated. Not always, but sometimes, the GFCI protecting the outlet I have this plugged into will trip. I have observed it, and note that it always trips just as the "out" light comes on & the SSR's activity light goes on. The project is in an aluminum chassis box, with the baseplate of the SSR grounded to the chassis. Weird thing is, it doesn't always do this. It just ran for close to 21 hours with no issues, and then suddenly started tripping, and now trips repeatedly as soon as the SSR output goes on.

I have checked & double-checked the wiring to ensure that there are no shorts. Is it possible that the SSR is leaking current to ground via it's baseplate? I know all SSRs leak some current through the AC output, but that's not what I think is causing this problem. GFCIs trip when current is leaking to ground (more precisely, when there is an imbalance between current on the hot & neutral legs, caused by a short to ground).

Thanks,
David

[Tech_Marco]

David:

That sounds very odd and it's the first time I heard about it. Well, anything could happen. Let's do this: take out the SSR and isolated it from the enclosure (no direct contact). Also, get yourself a voltmeter to measure if any leak between the back plate of the SSR and the enclosure. Of course, the SSR must be energized during the test.

Let me know how things work out

[dcarter]

Thanks for the quick response. Very impressive. I will pull out my multimeter & see if I can determine exactly what's going on. I just wanted to first see if this was a problem that had happened before. Sounds like the answer is no, so it's time to do some testing.

I forgot to mention that I did feel some slight tingling from touching the case or the PT100 probe when this started happening, and that's part of what led me to believe it may be current leakage via the SSR's baseplate. Of course, my first reaction was to double-check all the wiring & make sure nothing else was shorting to the case.

I will report back with whatever I find out.

Thanks,
David