Plug melt down

I can't speak for Hymotion, but my experience with other similar charger loads is that there is a pop every time the cord is connected, when there is arcing between the elements of the male and female connectors. Such arcing creates oxidation, which creates resistance. Such a situation is exacerbated by using a lighter gauge extension cord as well, something that the prior owner may have done.

The added resistance makes the charger see lower potential, and ask for more current. Suppose that the resistance at the plug is 1 Ohm, and due to the higher resistance, the charger is pulling 14A. That generates 200W of heat in a very confined space, and the copper has nowhere to conduct it other than the wires and the surrounding plastic plug. It is probably a safety feature that the plastic plug melts before the wire insulation catches fire.

 

Most likely cause is that the receptacle wore out and the plug no longer made good contact.

This leads to arcing under load in the connector which generates a lot of heat in a localized area.

An arc-fault circuit breaker would have likely picked up the fault and tripped.

Arcing is the most common cause of electrical fires - make sure your plugs fit securely and replace sockets as necessary at first sign of wear!

 

Yes, You were right the first time. The problem is generally in the extention cord. In fact the cord you show in the picture is a poorly designed plug for high currents.

Cut the female end off of that cord and put on a replacement that is rated for 20a.

Thanks,
Dan

 

That is not a good sign at all.
Replace the in car receptacle for higher current and a "dust cap".
After replacing, make sure the electrical contacts are sound and well made; replace that cheap extension cord for a heavy duty 20Amps one.

 

In addition to using a heavy duty extension cord, I was wondering if there is some kind of jell available that could be used to coat the AC plug contacts to insure the best contact between the cord, and plug built-in to the bumper connector. I saw such a jell used years ago on a battery operated RainMatic Water Timer. Each contact came from the factory with a dab of jell on it, which was suppose to insure better contact.

 

This is likely why the EVSEs (charging cord w/power brick for EVs and PHEVs, example of Nissan's L1 EVSE at My Nissan Leaf Forum • View topic - Inside the NA spec L1 EVSE) have warnings telling people to not use extension cords.

It's also likely the reason for the what part of what J1772 enables and NEMA codes (?) allow. From My Nissan Leaf Forum • View topic - Why the EVSE at all?

 

Aftermarket plugin kits don't have J1772 plug for changing. They all use extension cord as charge cable because it's universally available.
What you're talking about is wall socket to extension cord to EVSE/J1772 to car plug. We already know that is a no no. PHEV kits go from wall socket to extension cord to car plug. The part that burnt in OP is the part that plugs into wall socket. I would advice the OP to replace the charge cord and the wall socket too.

 

Well, if they did use J1772 natively, then part of the problem would be mitigated. When you unplug the J1772 plug from the car end, the high current draw would stop. Then, you'd unplug the regular plug (whatever the name for it is) on the other end, and presumably, you'd have much less degradation.

 

I've only had my PHEV kit installed for ~2 months, but I already noticed degradation of the NEMA contacts due to the arcing that occurs at every plugging/unplugging cycle. I was surprised at how bad it was already! My fix was to simply run a new outlet in my garage with a nice-quality 20A wall switch that I use to turn the outlet power off/on before/after I plug in the charger. I figured if I was going to destroy some contacts, I might as well destroy a $3 switch that is easy to replace. To my surprise, I don't get any arcing/sparking in the switch. It makes a much cleaner connect/disconnect, I guess. Or maybe it is having the neutral already connected when you cut in the hot? I'm not enough of an expert to know....

Incidentally, it also provides a handy way to reset the Kill-a-Watt without unplugging it. And the charger has it's own dedicated circuit now, too, which is nice in case I want to plug in something else in the garage (when are they going to make a hybrid minivan??)....

W.r.t. extension cords -- one of the first things I did after my conversion was go get a 10 gauge weather-proof cable and attach a couple high-quality plugs on the ends -- well worth it, although it was tough swallowing the $35 for all the copper (+ $$ for plugs). I also saw my power draw drop significantly (~100W) from the original extension cord I was using (which was a wimpy 16 gauge that I had lying around). After that experience I ran my new outlet with 10 gauge wire instead of the standard 12 (still used a 20A breaker, though). I figured it couldn't hurt, and that line will be spending a lot of time carrying ~10A in it, so shaving any wattage from my power consumption is the direction of goodness....

 

It might be Silicon Dielectric Compound. I've been putting a thin coating of that periodically on our block heater 3 prong 110 volt plug. At least no ill effects so far.

Maybe someone who knows will weigh in.

 

Mendel,

Silicon Dielectric Compound is likely it. From what I have read, it can protect electrical connections from moisture, and possibly high voltage arcing. That in turn should result in protection against corrosion. I could see using it periodically. It could be especially beneficial to cars that are kept and / or charged outside.