GFCI nuisance tripping from lights

[AlanM]

I have two d120s over the child care center tank I maintain that are now tripping the GFCI outlet.  It has happened twice to me, and since I'm not always there it could possibly leave the tank without power over a weekend, which worries me.  

 

The d120s are very simple inside, so I can open them up (and have) to try to make sure nothing is grounded oddly, but does anyone have any suggestions for where to check with a meter to make sure there are no extra paths to ground or what to look out for?  

 

The same GFCI used to trip when I had some T5 fluorescents on it.  At the time I attributed it to the current needed to fire the T5 bulbs on the Deep Blue fixture I had which might do things the GFCI didn't like.  Maybe just getting the plant guys to replace the outlet would get me one that wasn't as sensitive?

[Origami]

Alan, are the lights plugged directly into the outlet or do they go through some kind of a surge protector? If the latter, can you bypass the surge protector? Did you check for any corrosion or salt tracks on the boards, wiring, plugs, etc.?

[AlanM]

yes, they are on a power strip which then goes to a weather-resistant timer, then to an 8-port DJ strip, then to the GFCI outlet.

 

I can plug the timer box directly in to the GFCI and can replace the power strip.

 

I don't see any corrosion or salt tracks when I installed them a few months ago, but I can check again.

[Origami]

In years past, I had a similar situation but it involved my T5 lamps and a power strip with a built in surge protector. The startup current apparently caused some kind of backlash that triggered momentary current flow across the MOV's (metal oxide varistors) that went from hot to ground. That was enough to trigger the GFCI. I don't know if you've got anything similar going on, but a test that bypassed the strips and perhaps the DJ strip would be easy enough to do.

[AlanM]

Nice.  I'll definitely give that a try.  Thanks for the suggestion.

[Origami]

There's a substantial difference between the power supply in an LED fixture, and fluorescent or plasma lamps which require a surge to strike an arc, but it's worth a try. There's probably a switching power supply in the Evergrow unit and it may be surging at startup. Good luck.

[AlanM]

Hmm, could it have anything to do with the tingle of voltage I feel when I put my salty wet knuckle on the case of the fixture? 8)

[WilRams]

I have had a similar issue before with a Radion and then with an ATI fixture. Both times getting a higher quality (I went with LeGrand) outlet fixed the issue. I suspect just getting a new outlet would have fixed the issue as well as I read somewhere that they do recommend changing them out after sometime. 

[Origami]

Hmm, could it have anything to do with the tingle of voltage I feel when I put my salty wet knuckle on the case of the fixture? 8)

Possible, but that may be EMI coupling to the case. Is the case tied to ground inside?

 

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