Scary issue with Nema 14-50 adapter melting

[fluxemag]

I'm going to move my smoke detector in the garage closer to the outlet...

The UMC has a small pin inside that can bend when swapping adapter heads. Once it's bent you can no longer get it all the way on and have it click secure. I did this to my first UMC. It would have still worked but I didn't like that it wasn't snapped on tight. Not sure if this is a possibility in the OP's case.

 

[NigelM]

Mod Note: some posts went here - snippiness (but kudos to robertmgarrett for acknowledging his own action)

 

[qwk]

I disagree a bit here. Tesla should design the adapter such that it is either properly seated, or won't work. If the locking mechanism needs to be redesigned, then so be it, but while convenience of switching b/w adapters was clearly a priority, so should safety be a high priority, there should be a clear distinction between fully seated and not seated, no gray area.

Tesla has updated the UMC a few times now. The newest ones have smaller serial number lettering, and the tolerances on the adapter side make the adapters go on much more snug.

 

[Only Trons]

Just like @fluxemag noted: the locking pin on my UMC bent within one month of delivery of my Model S. I had changed out the adapter from the 14-50 to the 5-20 as part of testing the newly received 5-20 adapter. When I removed the 5-20 and attempted to put the 14-50 adapter back on, I noted the adapter would not fit up close. Further visual inspection revealed the bent pin. I took the UMC to our local SC and they replaced it. I ended up using the UMC to charge once or twice (with the bent locking pin) before I was able to get to the SC ---- but I was only charging to regain about 40 miles each time and I watched it fairly closely.

I don't have a smoke detector in my garage but given this thread, I will likely install one!!

@robertmgarrett: glad to hear that you caught this in time!!!!!!!!

 

[FlasherZ]

I suspect this is a continuance of the ongoing problem with melting adapters... The pins lose full contact between the adapter and the UMC plug head and it generates tremendous heat. 40A will create quite a heater. Normal circuit breakers will not trip under these circumstances.

This is the first case I've seen of severe melting. Most of the cases have been minor to this point.

When this happened to me, the entire UMC and adapter set were replaced, but I can see how this might continue to happen. I'm concerned with the design they used for those pins, which seem to bend fairly easily.

 

[RainmakerJL]

I disagree a bit here. Tesla should design the adapter such that it is either properly seated, or won't work. If the locking mechanism needs to be redesigned, then so be it, but while convenience of switching b/w adapters was clearly a priority, so should safety be a high priority, there should be a clear distinction between fully seated and not seated, no gray area.

saw that quote earlier as well.. agree with you efusco. Lets not start attacking people with issues. If it happened to me, i'd be more than a little worried too. The adapter should either work or not go live period. Its very likely this is a rare issue that is a result of a defect but given how much power these things are channeling and how expensive these cables are there should be protection from this type of thing built into the cord.

 

[apacheguy]

Tesla has updated the UMC a few times now. The newest ones have smaller serial number lettering, and the tolerances on the adapter side make the adapters go on much more snug.

Hmm. I still have the original, Signature-version UMC and adapter. Haven't had any problems, but maybe I should ask service for a replacement to be on the safe side?

 

[SFOTurtle]

Hmm. I still have the original, Signature-version UMC and adapter. Haven't had any problems, but maybe I should ask service for a replacement to be on the safe side?

I hadn't noticed any issues with my UMC (from February) but Tesla replaced it when I had my car in for servicing a couple weeks ago.

 

[scaesare]

. I'm concerned with the design they used for those pins, which seem to bend fairly easily.

Agreed. The weight of the UMC "electronics head" hanging (in many cases) on an already-lengthy plug/adapter combo doesn't help.

 

[Duckjybe]

I had a hot adapter as well and the whole UMC was replaced. Now every so often for peace of mind, after plugging in for 30 minutes or so, I check the adapter for being hot to the touch.

 

[FlasherZ]

Hmm. I still have the original, Signature-version UMC and adapter. Haven't had any problems, but maybe I should ask service for a replacement to be on the safe side?

A mandatory TSB to be covered during your first year's service appointment included replacement of the adapter if it was one of the older generations.

 

[mknox]

A bit off topic, but I found that the HPWC handle (that goes into the charge port) gets super hot too. Mentioned here.

 

[qwk]

I hadn't noticed any issues with my UMC (from February) but Tesla replaced it when I had my car in for servicing a couple weeks ago.

Yeah, service will replace items that have been revised to the latest revision(even if it works fine).

 

[StingerBob]

Slightly Different

I just felt like i should post this to make others aware. Hopefully this was just a case of bad luck in getting a bad adapter
Rob

A bit different in occurrence, but same eventual outcome. After 3 months with no charging problems, I noted a few nights ago on VisableTesla that there was no power from the wall. I checked the various connections, tripped and reset the circuit breaker, reset both screens, but no love. Called Tesla (2330 hours!) and got set up for a Ranger call. Replaced both 14-50 adapter and cable. Ranger showed melting on adapter, and indicated plastic cap was missing from one pin on UMC.

Old and new adapters were same series (-B) as were the UMC's (-D); however the manufacture month clock was 3 months later on the replacement adapter, but the new UMC actually had an earlier serial number ...26335 vs ...27224.

MS85 15827, 30 Jul 13

- - - Updated - - -

I just felt like i should post this to make others aware. Hopefully this was just a case of bad luck in getting a bad adapter
Rob

A bit different in occurrence, but same eventual outcome. After 3 months with no charging problems, I noted a few nights ago on VisableTesla that there was no power from the wall. I checked the various connections, tripped and reset the circuit breaker, reset both screens, but no love. Called Tesla (2330 hours!) and got set up for a Ranger call. Replaced both 14-50 adapter and cable. Ranger showed melting on adapter, and indicated plastic cap was missing from one pin on UMC.

Old and new adapters were same series (-B) as were the UMC's (-D); however the manufacture month clock was 3 months later on the replacement adapter, but the new UMC actually had an earlier serial number ...26335 vs ...27224.

MS85 15827, 30 Jul 13

 

[adelman]

One more thing you might consider - if that adapter got hot enough to melt itself, a good deal of heat was probably conducted into the 14-50 receptacle. You may want to pull the receptacle off the wall (or have your electrician do it) and evaluate it for thermal damage. Damage to the receptacle could cause a poor electrical connection with your new 14-50 adapter and result in a similar problem in the future.

If it were me, I'd just swap the receptacle. They're cheap.

If nothing else, grab a flashlight and try to look into the receptacle at the copper parts. Be sure they still look nice and shiny and not oxidized or discolored.

Ken

 

[robertmgarrett]

UPDATE: Tesla sent out their electrician of choice to inspect the outlet and wiring. They were both given the thumbs up. So all is pointing to the Nema 14-50 adapter at this time.

 

[huntjo]

Thanks for posting about this. I think I will turn down my standard amperage usage for a slower safer charge. No need to push my luck, even if it is a rare occurrence.

 

[loganss]

I charge using the 14-50 adapter daily but have the amperage dialed down to 30A and I'm typicallly charging from ~30-70 rated miles to a standard charge and no problems so far.

Thanks for keeping us updated robertmgarrett

 

[fcharland]

One more thing you might consider - if that adapter got hot enough to melt itself, a good deal of heat was probably conducted into the 14-50 receptacle. You may want to pull the receptacle off the wall (or have your electrician do it) and evaluate it for thermal damage. Damage to the receptacle could cause a poor electrical connection with your new 14-50 adapter and result in a similar problem in the future.

If it were me, I'd just swap the receptacle. They're cheap.

If nothing else, grab a flashlight and try to look into the receptacle at the copper parts. Be sure they still look nice and shiny and not oxidized or discolored.

Ken

If more current than the outlet could support was passing by the outlet, the breaker would have tripped. Which was not the case.

In retrospect, it does not need that much energy to burn some rubber, and all it needs is a few ohm of resistance due to a bad contact.

 

[pilotSteve]

This points out the difficulties of manufacturing "consumer" equipment that handles 10kW of power! The only comparable item around the home might be a generator with cord/plug or a dryer cord. And these kind of items do *not* have snap on/off plug adapters! Tesla is breaking new ground here and I am amazed how well it works. But I always feel the cables and adapters (and HPWC box) depending on what I'm using shortly after charge starts "just to be sure".