This post is just a heads up for anyone still using the old Xerox inline GFCI power cords. Mine seems to have developed an internal short after 8 years of service and, despite all the damage in the pictures, everything still worked. Well, except for the GFCI in the cord that should've tripped but didn't. So if you still run on one of these, I suggest trashing it! I only noticed the issue because the heatsink on top of my panel was way too hot, and when I opened up the panel to inspect the inside I could feel a pretty excessive amount of heat from a couple parts. Everything looks good on the inside though, no signs of damage. The cord is another story, as you can see in the pics.
I have a 30A GFCI breaker, 4 wire dryer cord, and new 30A 4-prong male/female twistlocks coming. I'm also moving the brewing operations into the garage once I finish ducting for my new (to me) hood. Previously I was wheeling everything to the driveway and brewing out in the elements. I'll likely mount the panel to the wall instead of it's existing mount on an arm of the brew stand which will also mean the replacement cord will experience less movement/stress
Mine seems to have developed an internal short after 8 years of service and, despite all the damage in the pictures, everything still worked.
The melting you're seeing is not from a short but because of a poor connection between the black wire and the connector you added. It may have originally been done a bit loosely and worked itself looser over time, eventually to the point where it was loose enough such that current was flowing through a smaller area which in turn creates more heat. Extra heat creates more issues and thermal expansion/contraction just making things worse, and eventually you get a runaway condition and it all melts.
In the first pic I also see lots of broken copper strands. It could be that the strain relief was loose and pushing/pulling from movement causes strands to break over time, reducing the area where the current flowed through. Not sure. breaking strands over time would have the same result: Smaller area for current to flow through which creates more heat.
Well, except for the GFCI in the cord that should've tripped but didn't.
No, a GFCI would trip if it senses an imbalance between lines so that wouldn't happen here. If you had an actual short (one of the HOTs to GROUND or NEUTRAL) your 30A breaker in your home's electrical panel would have tripped.
I only noticed the issue because the heatsink on top of my panel was way too hot, and when I opened up the panel to inspect the inside I could feel a pretty excessive amount of heat from a couple parts.
Not sure why your heatsink on top of the panel was too hot. I don't see how that's related. Normal for everything in the panel to be a bit warmer if you had a heat source at the input connector/receptacle that got hot enough to melt wiring however, but it shouldn't be localized to the heatsink any more than any other part.
Either way, best to be safe and use an actual GFCI breaker as you're doing now that meets the 4-6ma NEC trip limit. Good move! Cheers!
Link Posted: Thu Sep 10, 2020 2:28 pm Post subject:
You're right, the connector was added by me and I cannot deny the possibility that I borked something when installing that. All the screws were still tight and the wire connections appeared to be in tact though. Even the damaged black wire was still firmly connected to it's respective screw. The copper strands near the screw were originally covered in melted insulation (picture 3) which fell off when I messed with it and the exposed copper strands are what was underneath (picture 1). I agree the periodic movement of the panel on it's swinging arm (tv mount) likely stressed the connections either somewhere in the wire or possibly in the connector over time until things were rubbed/exposed/shorted.
One test I did before I tossed the whole thing in the trash was I cut all the damaged wiring/insulation off, cut off 6 inches or so of the gray outer insulation, stripped an inch of the inner blue/green/black insulation and did continuity tests between the different wires. There should have been none but I was getting continuity between the two black hot wires and the ground which tells me there may have been something wrong somewhere else in that cord. I decided it wasn't worth investigating further though since I already bought everything to replace it.
For the second picture - my cord had a green, a blue, and two blacks. One of the blacks was fried and the other was fine - the second picture is the view from one side where everything still looks OK.
I don't have any real explanation for why the heatsink was hot either, but I am hoping it will be resolved by addressing the short in the power cord. If I still have issues after the new power setup I'll report back.
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