Mar 30, 2013
joepruitt I plugged in the ModelS today and the power ring turned red. Looked at the Universal wall connector and it was red. I tried unplugging it and replugging it in and no better. I then took the NEMA 14-50 adapter off from the cable and this is what I found.
I've got a 50-amp dedicated line from a single breaker into my garage so I'm only wondering if this could have been some sort of power surge. I called service today and was able to talk to a tech after hours (more awesome Tesla service) and he said he hadn't heard of this happening before.
Meanwhile, I'm stuck in Sammamish without charging for the weekend. Luckily I have a 85kw battery so I should be good until I take it into the service center on Monday. They said they have extra cables I can swap this one out for. My main concern is a fire hazard if this happens again. Anyone have any ideas on how to troubleshoot on my end?�
Mar 30, 2013
mitch672 I know this not the first time this has happened to a UMC, "Cinergi" (Ben) had a similar problem with his, and it needed to be replaced. By any chance have you been using 208V, more than 240V? I think some of these UMCs might have manufacturing defects where the wire connecting to the UMC socket possibly has a high resistance connection, causing the pin to heat up more, leading to an early failure of the socket...�
Mar 30, 2013
joepruitt Not sure what it was using volt-wise and I can't check it now. Service did say they would replace the cable so they are covering it with the warranty. I'm more concerned with it happening again. I was an early owner so hopefully service can tell me more about the problem when I take it in on Monday.
-Joe�
Mar 30, 2013
Discoducky So, we are traveling from Issaquah (right next door to Sammamish and if we were home you could use our 14-50) and are currently in Palm Springs when our UMC failed. I also saw the red ring, but my cable looks other fine than the metal locking tab at the top was pushed down and was touching the closest pin. I called 877-79-TESLA and talked to TJ who will try to get us in touch with the LA service center to get a new cable sent out Monday. Clearly they are having issues with the UMC's.
Here's what mine currently looks like. I've bent the tab and it engages properly, but the cable still doesn't work.
Thank goodness we have had a J1772 charger within our remaining range!�
Mar 30, 2013
mitch672 Cinergi also had a very early Model S, so perhaps they've improved the UMC manufacturing already.�
Mar 30, 2013
FlasherZ Looks like a bit of arc'ing took place there, I hope it's a one-off. I was a bit concerned with the size of the pins on the adapter, they seem a bit small for 50A rating.
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Red ring, red light on UMC, or both?
Could be a bad receptacle / ground / etc. supplying power. I assume you've tried it at different places on different receptacles?�
Mar 30, 2013
cinergi Joe -- did you swap the adapter on the end of the MC recently (e.g. to the NEMA5-15 for a 120 connection and back to the NEMA15-50)?
Mine failed in a similar way; the material it's made out of can withstand (melt, but not start on fire) some ridiculous temperatures (I measured it -- forget the numbers I saw). It's still obviously concerning and a safety hazard (at the very least, you'll get burned touching that plug while it's charging). I'm sure they'll send yours in to the engineers like they did mine and study it.�
Mar 30, 2013
Discoducky Red light on UMC, 4 flashes (https://www.teslamotors.com/sites/default/files/blog_attachments/ms_mobile_connector_guide.pdf) and manual says it's lack of ground. It's also a red ring on the charge port on the car. Another outlet shows green on the UMC, but doesn't work on the car. I'm thinking about rebooting the car (center and 17" display) to see if I can get it to work.
Another question I'd like to know if the adapter locking tab on the cable (wall outlet side) has an electrical connection? I'm assuming that it does since the UMC manual says that 5 flashes is "Sense fault circuit" which is "Make sure the Mobile Connector's adaptor is properly attached". SO if I don't get 5 flashes I'm assuming that the tab is locking properly.�
Mar 30, 2013
FlasherZ The sense fault circuit has to do with the UMC's detection of which adapter is there. The locking tab is not part of that, from what I have seen.
I helped troubleshoot an issue a week ago where a NEMA 14-50 receptacle had a bad ground clasp; when you held the plug a certain way it would work but then it would stop after detecting a ground fault. I had to "adjust" the ground pin so that it would hold the ground pin effectively.
It *could* be that there is a broken connection to the ground pin, but I'd start looking at the circuit(s) first.
I have found that if the UMC detects a ground fault, the car will display a red ring. Fix the power problem and you'll likely get it to work.�
Mar 31, 2013
Daniel Scherer What is the yellow stuff? Was any kind of lubricant used inside the connector? I thought about putting Dielectric grease inside mine to help keep out moisture.�
Mar 31, 2013
Discoducky Using known good receptacles and both adaptors fit/lock properly now, the light turns green on the UMC and when connected to car does NOT lock into the car and does NOT charge. I'm currently charging from J1772 and it's nearly fully charged. I'm bummed that the UMC does NOT indicate their is an issue. I'd rather get a known good UMC to test before doing any further troubleshooting.�
Mar 31, 2013
FlasherZ Does the ring stay white, or turn blue, or some other color? Does the car show any indication that you've connected a charge connector?�
Mar 31, 2013
qwk I had the exact same problem. Bad UMC.�
Mar 31, 2013
Discoducky White, no indication the UMC has been inserted. But I nearly fully charged from J1772 today.
How long did it take to get a new one from TM? I've been told that the LA store will be calling tomorrow morning and after triage *could* overnight one from their or another close store.�
Mar 31, 2013
qwk They overnighted a UMC from the service center( used), because they are on back order.�
Mar 31, 2013
FlasherZ Yup, failed pilot signal. Bad UMC. Good luck.�
Apr 1, 2013
joepruitt Just got back from service where they replace my UMC. They looked at it right away and said it had to be replaced anyway because it was an early model and I heard something about a tech note on the 14-50 adapter. For those early sig owners out there, it might not be a bad thing to call your local service and ask them if you need to get yours replaced.
Bottom line is that Tesla service rocks. They had me in and out in 15 minutes with a brand new UMC and adapter, tested the connection, and installed my under-display cubby that I never got on the initial delivery.
-Joe�
Apr 1, 2013
Elshout I purposely charge at either 30 or 40 amps, never at 50 amps that that my line is capable of.�
Apr 1, 2013
FlasherZ This is probably the most misunderstood portion of EV charging loads and circuit capacity.
Your branch circuit and receptacle is rated for 50 amps intermittent load. The NEC distinguishes intermittent load from continuous load, which is defined as load applied constantly for 3 hours or more. Furthermore, NEC dictates that all EV charging loads, regardless of expected charge time, are to be treated as continuous load.
Compare an EV load, which draws a constant amount of current, to that of an electric oven or range, where the elements cycle on and off to maintain particular heat settings, or to an air conditioner unit, where the compressor cycles on and off. Because the EV charging load never cycles off until the charge is complete, there is a much greater chance for a significant heat build-up, and in some cases, a 30 amp continuous load on a 30 amp rated receptacle has resulted in complete destruction of plugs and/or receptacles.
This is why the NEC requires the rating of branch circuit wiring, devices, and overcurrent protection to be at least 125% of the continuous load; hence the 40A charging limitation on a 50A circuit, and the 80A charging limitation on a 100A HPWC circuit.�
Apr 1, 2013
mknox What FlasherZ says, plus you shouldn't even be able to turn it up beyond 40 amps from the touchscreen anyway.�
Apr 1, 2013
FlasherZ I dropped a note to my service center about this as well. I noted that my plug was getting very hot to the touch this weekend. I suspect I might be one of those "earlier" UMC holders.�
Apr 1, 2013
NigelM I was at Tesla today (getting tires for the Roadster) and they did confirm that certain early UMC's are having the connector plug exchanged. Also asked me to drop by with the UMC at some point so they could inspect the cable.
You can check if there are any issues simply by pulling off the plug adapter and checking the inside for any signs of overheating or melting. Mine looked OK but was on the list to be changed in any case.�
Apr 1, 2013
FlasherZ Thanks Nigel. Service manager and I were swapping e-mails earlier today and he mentioned he would order one for me.�
Apr 1, 2013
Discoducky Vince at the LA service center is going to overnight a replacement UMC to arrive tomorrow to us in Palm Springs. Since we are leaving Wednesday morning back to Seattle it is a very necessary item and very much appreciated!
And thanks very much to FlasherZ and everyone else for all the great advice!�
Apr 1, 2013
cinergi It should be cool, maybe luke-warm to the touch. Never anywhere near hot. I think mine was going well over 200F and now it runs at like 80F.�
Apr 1, 2013
Puyallup Bill Sorry to go off topic, but that comment raises a question. My car has dual chargers, and I have only used the charge cable with the 14-50 adapter. The charge screen shows 40 Amps available - if I use a Roadster adapter (70 Amps) or a high power wall changer, does the 40 Amp figure change?�
Apr 1, 2013
dsm363 You may have to dial it up on the screen but it changes. When I've plugged into a HPWC it went up to the max that was being offered (80A when I used one).�
Apr 1, 2013
mknox Mine is the same, and I believe it's because it senses the NEMA 14-50 adapter and "knows" 40 amps is the max it can draw from that. If I pull in to a public station, my screen shows 80 Amps until I plug in using the adapter, then it seems to adjust down to the capacity of the charger.�
Apr 1, 2013
hcsharp The EVSE or "charger" as they're commonly called lets the car know how many amps are available on the pilot signal. Examples of EVSE are the HPWC and the UMC. In the case of the latter, it senses which adapter you have plugged in and lets the car know the amps available from that type of receptacle. It's up to the car when it starts drawing current to make sure it doesn't draw more than the amount of amps that the EVSE said were available as communicated over the pilot signal.
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As FlasherZ and others have pointed out, it's critical that you install any charging system, receptacle, home-made adapter, extension cord, etc using the right size of cable and breaker according to the NEC. One reason is that the UMC will auto-sense the adapter and signal the current accordingly. But if you have a weak link that can't handle the amps, you have a recipe for disaster. Please don't use a sub-standard cable or cord thinking that you will just limit the amps from the screen.�
Apr 2, 2013
ElSupreme I just looked at my adapter and UMC socket. I have a small amount of melting, and some heat build up when plugged in. I also found out that my adapter doesn't actually latch to the UMC outlet and wasn't 100% seated.
I'll give Atlanata service a call today and see what they want to do.�
Apr 12, 2013
pete8314 Mine has melted. It was always very hot to touch up to the adaptor (not skin sizzling, but not particularly comfortable to hold onto for very long). Charging was always at 40A (via the 6-50 adaptor). Adaptor was still providing a charge to the car, and showing a single green light when not charging. Sent an email to Ownership, so waiting on reply. I'm overseas at the moment, but my wife noticed a burning smell the day I left, so she unplugged it from the car, but didn't notice the outlet had melted, until today when I asked for it to be plugged back in. I assume stuff melting inside the outlet which caused it to pull away from the wall, she's not had a chance to check. Not good.
�
Apr 12, 2013
markb1 That's crazy. Don't use a damaged outlet. Shut down the circuit breaker until all the damaged parts are replaced. This is the sort of thing that can burn down your house. And I would imagine, if your house burns down now, your insurance company will deny your claim as the outlet was used after the damage was noticed. (Not that this is the worst thing than happen when a house burns down.)
Edit: I hope I misread that. I occurred to me that my interpretation is off, and you didn't ask her to plug it back in after the problem was noticed.�
Apr 12, 2013
mknox Those photos look like a loose socket connection and not a UMC connector fault. If the plug blades are loose in the socket, especially with high currents, overheating and results like this are common.�
Apr 12, 2013
jerry33 Perhaps Tesla should supply a heavy duty receptacle. Overheating seems far more common than I would have expected. I keep mine at 32 amps as that charges fast enough for me.�
Apr 13, 2013
FlasherZ I've seen a number of receptacles lately with loose connections, either on the ground pins or some of the hot pins. This has been especially the case on some Hubbell 14-50's that I've seen installed.�
Apr 13, 2013
pete8314 CorrectI try not to deliberately injure my wife, or burn the house down when I'm not there
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I don't think so. It was a very tight fit, it wasn't moving anywhere. The weight of the cable was supported by a cable hanger on the wall, so there was very little downward pull.
If you mean the actual socket/outlet fixed to the wall, then it's possible I guess. It was obviously installed after the house was built, so it's secured to the wall with the little tabs, but still, there wasn't a lot of pull on it, and I think I would have noticed the weakness when unplugging it.
My local Service Manager will be swinging by in the morning to delivery a replacement UMC (go Tesla!), obviously for use with a lowly 110v until I get the 6-50 fixed. He said over the phone (to my wife, so facts might be getting distorted) that it looked like the 'springs' in the outlet had opened up as a result of excessive heat. I've no idea what that means without seeing it myself. I'm sure he'll take a look when he's there.�
Apr 13, 2013
Bearman Somebody should take a deeper look on these issues, one burned down house later is too late.�
Apr 13, 2013
mknox It sure looks like the heat was coming from the socket side and not the UMC. There could have been a loose connection of the house wiring to the receptacle itself which would also generate heat. This heat then caused the nearest melt-able substance (the UMC plug) to melt. You or your electrician should check the wires behind the receptacle also.�
Apr 15, 2013
pete8314 Here's some more photos, I agree, it appears the heat was coming from inside the socket. Jack (Dallas SC Manager) did a great job of dropping by a replacement (with the shiny faceplate!) within a day, he'll be taking the melted unit to the factory today for further analysis to determine whether it's a warranty claim or if I need to pay (and go after the electrician).
�
Apr 15, 2013
FlasherZ From the pics, this *looks* like there was a loose connection from wire-to-receptacle, as if the wire wasn't fully in when tightened, or the connection weren't torqued tight enough (or at all). That said, looks can be deceiving. Good luck.�
Apr 18, 2013
orlando My UMC is SUPER hot from the plug that goes into the wall (14-50) to the Tesla box... Just called - will report back on cure.�
Apr 18, 2013
mknox I would suggest turning the amperage down on the touchscreen to the lowest you can get by with until this is resolved. I drive about 100 miles a day and can get by at 16 amps overnight. If I start charging at 7:00 PM, it's done sometime around 5:00 or 6:00 am.�
Apr 18, 2013
FlasherZ A new 14-50 adapter will likely solve your problem. Call service and they'll ship you one.
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Today I could smell melting plastic as well... my UMC plug is beginning to melt at the 14-50 adapter. On my infrared thermometer it is recording 227 degrees F.�
Apr 18, 2013
DocDog Is this still the original UMC with your sig, or is this a replacement?�
Apr 18, 2013
FlasherZ It's a replacement, but a very early replacement (the one with my car wouldn't open the charge port unless you touched it to the rear glass). So it's a part of the "known problem" children that just hasn't deteriorated to the point of melting until recently. Service center is sending one my way tonight.�
Apr 18, 2013
DocDog Good ol' Leo.�
Apr 18, 2013
FlasherZ Matt's doing the legwork. Leo just handled the call.�
Apr 18, 2013
ElSupreme I was having this problem also. I am swapping out my charger tomorrow or Saturday at the Marietta (Atlanta) service center.
Here are some pictures:
There is some very noticeable melting on the right pin in this picture. There is some barely noticeable discoloration on the left pin.
This mirrors the above picture, melting noticeable, and discoloration.
The serial number of my UMC. I didn't get a UMC with my car, the Atlanta service center gave me one of theirs which was circa early Signature cars.�
Apr 18, 2013
yobigd20 Is that a 6/3 cable or 8/3 cable? 8/3 might be too small and might not be safe...
personally, I put an exterior RV NEMA 14-50 outlet inside my garage. ran 6/3 cable in conduit to the outlet box. the metal box seems safer than having a hot receptacle embedded in the drywall. very sturdy too. could probably even give it a good whack with a baseball bat without damaging it.
�
Apr 18, 2013
FlasherZ The HPWC uses #6 type EV cable to the car for delivering 80A, as well as internally in the HPWC. The wire used is rated at 105 degC, good to 84A.
The UMC appears to use #10, which is good for 42A at 105 degC insulation rating. It may be #8, but I don't think so.
(Note that UL listing doesn't require the 125% sizing figure for devices that have been listed and tested, so the HPWC & UMC internal wiring doesn't have to be bigger. Also note that #8 can be used for wiring a 14-50 when it's in conduit, but cannot be used if Romex is used - because Romex must be derated to the 60 deg C value regardless of internal insulation rating.)�
Apr 18, 2013
yobigd20
That's what I'm asking about - the wiring of the 14-50, not the charging cable wire. I'm wondering if 8/3 was used here to wire up that 14-50 instead of 6/3.�
Apr 18, 2013
jomo25 As a point of information, the UMC is not UL Listed.�
Apr 18, 2013
Duckjybe Same here. I just went out to the garage to check mine and sure enough it was almost too hot to touch! I am getting this discoloration around the right hand pin (as seen in the picture below) as well. I dialled down my current to 28A until this gets resolved.
�
Apr 18, 2013
jerry33 I run mine at 33 amps. It's warm but not hot. The cable is warm as well.�
Apr 18, 2013
FlasherZ For what it's worth, #8 wire will carry 40 amps without an issue, even if Romex. NEC just requires you derate it, meaning 8/3 Romex can't legally be installed. That said, the wiring wouldn't be a problem and #8 in conduit won't be an issue.�
Apr 18, 2013
efxjim You have to tighten the screws quite tight onto the wire. I find people do not apply enough torque to make a proper connection. There are inch or ft\lb specifications for the connections listed for the recepticals. If one current carrying wire is getting hotter than the other one then a connection is usually loose. We used to have to tighten our 30A twist lock plugs every 6 months or so or they would start heating up due to lack of tightness. I think they worked loose from all the handling.�
Apr 20, 2013
Duckjybe I took my UMC back to the Tesla Service centre in Toronto and they gave me a new one with a new 14-50 adapter. Unlike my old one, this one has the chrome cover over the button. Plugged in for 1/2 hour at 40A and it is still cool to the touch at the elbow (before it was almost too hot to touch). All is great. The cable gets a little warmer as you run your hand down to the rectangular box, but I would think the electronics in it would heat up a little so this is normal. I would recommend owners check their 14-50 connection for excessive heat.�
May 4, 2013
jdb Good information here. My 14-50 has been getting more difficult to work, have sig vehicle, finally stopped working yesterday, getting only red light. So switched to the 110v outlet to charge car overnight (that works fine) and called electrician to check garage 240v outlet next week, thinkng it was the wall socket. After reading this thread checked 14-50 and sure enough, light corrosion inside on pins. Used pen knife to scrape off, now working OK again. Like minor battery corrosion on ICE battery connections. I had noticed it was somewhat hot to touch when charging past few months. Plan to take car to Tesla service center for 6K tire rotation in next few weeks so will ask for replacement 14-50 when take to service. This is good forum, thanks.�
May 4, 2013
Doug_G My 14-50 adapter gets a little warm while charging. Maybe I should have a closer look at it...�
May 4, 2013
FlasherZ Yup - watch it carefully. Mine seemed to be fine, but then one weekend I noticed a "warm smell" and it got worse quickly.�
May 11, 2013
Lyon Mine got melts tonight, too. My day's did about a week ago. His UMC actually stopped charging and showed a red light, fortunately I just happened to touch mine tonigh and found it to be too warm to touch for more than a moment.
I got made fun of on another thread for buying a second UMC as a back-up. I gotta say, I'm feeling a little smug at the moment. :wink:
�
May 15, 2013
Lightning Jeff Similar, perhaps minor, melting issues on my (faceplate-less) mobile connector:
When I first got it, I was getting temperature readings closer to 100 - which also seemed somewhat high, but it's much hotter now.
I'll be stopping by Seattle SC this afternoon.�
May 15, 2013
SFOTurtle How long were you charging on the 14-50 before it melted?�
May 15, 2013
Lightning Jeff In my case, hard to say. It had been charging for perhaps a couple of hours last night when I thought to check it after seeing this thread. But I haven't had the 14-50 adapter off of the connector since I took delivery back in February. My guess is that the melting has been an ongoing process, rather than an instantaneous event.�
May 15, 2013
drees Looks like there might be some sort of pin alignment issue contributing to the issue?
Too bad the pins on the adapters aren't as tough as the ones on the car.
144F is HOT especially considering that you're measuring the outside of the connector - the pins must be at least 20-30F hotter.
Personally I wouldn't charge at more than 20-30A or so until Tesla figures this one out and periodically check temperatures after 30 minutes of charging.
The real issue is that if you're using a timer, you might never notice the plug overheating until it melts, especially if you leave your UMC plugged in to the wall.
Is everyone who's had an adapter melt letting the "brick" hang from the plug as Lightning Jeff is in his pic? That puts a lot of strain on the connector - you can see that Lightning Jeff's adapter doesn't appear to be fully seated.
In the pics on this thread I also notice that the bottom of the power pins is the primary melt point - this reinforces the above theory that there is too much strain on the adapter.�
May 15, 2013
Lightning Jeff It's actually the connector pins, so if this is a flaw, it may be a more expensive one to fix. And yes, they seem tiny for the amount of current they're moving.
I'll be interested in what others do, as this always seemed a little off to me - to the point that I've thought about mounting a bracket for the "brick" to sit in and relieve that strain. That said, I actually don't think the strain is that great. I'm not sure that gap you see really is one - or that, given how tight the two pieces fit together, it contributes to any actual misalignment of the pins. But, you may be onto something.�
May 15, 2013
Lightning Jeff The Seattle SC very quickly replaced my UMC. Happy to say, I now have a faceplate.
The new one gets warm, but not the 140+ I saw with the old one. This is after about 90 minutes charging at 39 of 40 amps:
I am still worried about the size of those pins, though - they seem awfully small.�
May 16, 2013
Ingineer I recently opened one of the UMC's up, but it's a pretty destructive process due to the housing overmold and it being glued shut. It's a "one-way" trip, so definitely do NOT try this at home!
Tesla is really pushing the limits on the UMC design! When used with a 50A adapter, It's putting out a 66.7% Duty cycle, which equates to 40A. They use paired 2.5mm wires for each side of the line, (Equivalent to ~#13AWG) and inside the box they use the same P&B relay ClipperCreek uses on the LCS-25, a single 30A rated relay. (at 40A!) Now since it's almost never going to be expected to interrupt any sizable current, this is probably fine as long as the contact system in the relay is low enough resistance and there isn't too much heat dissipated. I haven't done any thermography yet.
It's arguable that splitting the high-current between 2 smaller conductors is better for heat-dissipation, but then you sometimes have pesky termination issues. Inside the UMC, Tesla welds the 2 conductors to a little square terminal, then screws this to a PCB terminal. So this is a good termination and it looked well-done by my assessment. Having 4 smaller wires instead of 2 larger ones definitely makes for a smaller, more flexible cable overall, so regardless of any potential current handling gain, it's good ergonomically.
I definitely don't like their interchangeable right-angle plug connector design. First off, if you are going to do right-angle, why not make it symmetrical? That way you could flip it 180 degrees if your outlet is installed upside-down. (Patent-Pending! =)
Their "dongle" design makes for elegant and simple plug adapters, but it ends up being a really big blob, especially when used on smaller outlets (NEMA 5-15). This will put even more stress on the outlet, with the high bending moment due to hanging the weight of the UMC and cabling off a long adapter conflagration. I think I prefer having a short length of cable for each adapter, as this makes the final plug smaller, more compact, more flexible, and spreads out heat. This is the design choice I made on the EVSE upgrade. I use a NEMA L6-20 (L6-30 on higher-power units) as my intermediary adapter connector, which is a good design, positively locks, and still very compact. Then I use a short cable to connect the adapters to the plug, and all connections are welded and fully overmolded. This maintains flexibility, reduces physical stress on the outlets, and spreads out any heat generated. It also means you don't need an adapter at all to "go native". I decided against right-angle choices on most adapters because there is no standard for outlet installation in the wild, and you could very often end up with a 180 degree wire exit, which is not a good idea.
-Phil�
May 16, 2013
waidy I just use the UMC with the newly improved 14-50 adapter that was freshly evolved by Ingineer. It is now 2 hours into charging at 40Amp 240V, my Cen-Tech Infrared Thermometer gun reads 89.6 degree F at 14-50, and 121.4 degree F on the UMC body.�
May 16, 2013
Doug_G The contacts on the T92S7D12-24 relay has "Rated current" of 30A, but if you look at it in more detail they have a "limiting continuous current" of 40A.
The datasheet specifies how many operation cycles you can do at what current. At 40A/277VAC they are rated for 6000 cycles. Mind you, it is likely that Tesla is only operating the relay with the power off, since the car has much larger contactors. (Except they probably pull power immediately if a ground fault is detected - but you can do that 6000 times.)
So it does look like they are respecting the limits of the part... but yes, this isn't a conservative design!�
May 16, 2013
FlasherZ My pins reached over 200 degrees after the UMC adapter melted. Tesla replaced, it's working cool again.�
May 19, 2013
Neech Did anyone notice if the power cable felt hot before the plugs melted? I noticed yesterday that my cable was very warm. Also, the unit with the green lights that show if it is charging properly is on backwards (it faces the wall when it's hanging). Now I'm a little worried it might not be wired properly. I'm going to get a bracket to put that unit on so it is not just hanging and I can keep an eye on the lights.�
May 19, 2013
FlasherZ Yes, it does, because the heat is carried through the wires, but there will clearly be a hot spot. In my case it was the connection between the UMC adapter head and the adapter itself. In one case on this forum, it's clear that it was a faulty receptacle rather than the adapter because the hot spot was at the 14-50 blades.�
May 19, 2013
PhilBa My new garage is getting wired right now so I am keenly interested in this topic. Several things to consider:
- With that much current, contact area is a key issue. I'm pretty sure the spec assumes full contact along the entire pin/receptical. Any less contact area means higher current per unit of contact area and thus higher heat.
- It looks like all the heat problems occur with the 14-50 connectors and not the screw terminals on the 14-50. Given that the early UMCs are getting replaced by Tesla, that says they are assuming insufficient contact area.
- 14-50s in general weren't designed for a lot of insert/remove cycles. How many times would a dryer be plugged/unplugged? Care in inserting and removing is important. Try to be perfectly straight. It looks like the lower pins are where the problems occur. The right angle plug probably encourages putting upward torque on the plug when removing it, thus causing wear on the lower pins.
- Dialing down the current mitigates the problem because it drops the amount of current flowing through the diminished contact area thus reducing the heat.
- Making sure the 14-50 is very securely installed is important. No flex. Metal boxes (no plastic), securely mounted to a stud, everything really tightened down. A good electrician should do this but they sometimes cut corners.
- Make sure that your UMC doesn't place stress on the outlet. Over time, movement could cause wear and reduce the contact area.
- Something I don't know but will ask my electrician (who seems pretty good) - are there different grades of 14-50s? I see ads for industrial grade 14-50s. This is one area I won't skimp on.
�
May 19, 2013
FlasherZ Different manufacturers test for different cycles. There isn't a standard, per se, for industrial vs. recreational grade, etc., but some may be built to be tougher (for example, 14-50's are used for RV's, so RV parks will experience a good number of cycles).
Most of the failures we're seeing are not related to the 14-50 blades, but rather the pin surface area between the adapter and the UMC's plug-head.�
May 27, 2013
jerry33 A 14-50 is an RV plug, not a dryer plug (dryers use 30 amp circuits, not 50 amp). RVs are plugged in frequently. (Not saying that you're incorrect about the 14-50 not being good for that many cycles though--that seems to be normal even though RV plugs tend to be unplugged frequently)�
May 28, 2013
mknox NEMA 14-50 outlets are most commonly used for electric ranges. Most homes in my neck of the woods come with these pre-wired in the kitchen.�
May 28, 2013
dave So I caught my car still charging when I left for work this morning. It had been charging for about 4.5 hours on my 14-50 outlet. The charging cable was quite warm, but the connector going into the outlet was HOT. I really can't guess what the temperature was, but I was only able to touch it for about 3 seconds before having to remove my finger due to the pain from the heat. Yeah, I know, not very scientific. Maybe I have a low pain tolerance!
In any case, is that level of heat normal? Are you all able to to comfortably touch your connector after a few hours of charging? I have to admit it made me quite nervous. I don't know how hot things need to get to catch fire, but I am not used to my electronics getting that hot, and I'm wondering if I'm too sensitive or if I potentially have a bad adapter too.
your thoughts?�
May 28, 2013
jerry33 No.
Yes. I just had my UMC replaced today for being hot (Called service before it actually melted.) What I felt was:
Panel breaker slightly warm (normal)
14-50 receptacle cool (normal)
14-50 adapter warm (normal)
UMC adapter end hot
Cable between UMC adapter end and GFI hot
GFI hot
Cable between GFI and charge port connector cool (normal)
Charge port connector cool (normal)
This was after about thirty minutes charging at 33 amps. I suspect it would have melted had I not stopped charging to let it cool down (there were 31 miles of range left when charging started)�
May 31, 2013
dave Thanks for the advice jerry33. I had service swap out my UMC, and it is now much cooler while charger. I can comfortably hold the adapter while charging, and it is only "warm". There was definitely something wrong before.�
Jun 15, 2013
evmile Phil, Have you determined how the adapter plugs are coded? Have considered offering a TT-30 for instance?�
Jun 25, 2013
Ingineer Yes, they use a simple resistor. I doubt there is much interest in a TT-30 adapter. Even if the Model-S would charge at 24A on 120V, it's still only 2.88kW, which is damn slow. Most all RV parks that have a TT-30 are going to have a 14-50.
-Phil�
Jul 10, 2013
mnx Looks like I'll need to get my UMC replaced as well. I went to unplug it after topping the car up before a trip and I nearly burned my hand. The adapter and the cable between the adapter and electronics box were very hot. I've got some discolouration inside the adapter but it doesn't look like it's started to melt yet.�
Jul 12, 2013
stsanford Glad I found this thread... We've been having trouble with my circuit breaker tripping. Car not charging... My electrician was over 3 times! Everything except the wire was replaced. Now he felt the right-angle connector and it was "burn your hand" hot. Called SC and will have them replace. Will dial back the amperage....�
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