NEMA 14-50 meltdown

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bwilson4web

bwilson4web

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Could not charge at lunch only to find:
upload_2021-8-3_16-5-42.webp

The plug shows melted plastic on one pin. I bought a replacement from Granger. I can clean up the pin with a Dremil tool and sandpaper.

I also left a note that they can decapitate the plug and wire directly. Bolted in eliminates a source of another plug-socket hotspot.

Regardless of which approach, I’ll use an IR thermometer to measure each side after charging. No need to melt it down in another six years.

Suggestions?

Bob Wilson
 
I think the reason is printed right on it. Next time, Leviton or Hubbell, and be liberal with the DeOxit.

_H*
 
Makes me feel better about having to hardwire my home EVSE due to electrical regulations (all 240 V outlets require GFCI in my state).
 
You also might consider replacing it with a industrial version. Commercial receptacles may not handle high current draw for sustained periods of time as well. If you got the receptacle from a local big box hardware store you can probably assume it's commercial not industrial grade. An electrical supply house will have the larger industrial version. They are physically larger in diameter.
upload_2021-8-4_8-19-56.webp


Cooper/Eaton 5745N or Hubbell HBL9450A are examples the industrial receptacles. An Industrial grade outlet will have a larger face which requires a receptacle cover with a 2.48" ID hole. (Mulberry 97223)

They are also considerably more expensive.
 
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Here is the failed plug:
upload_2021-8-4_15-52-14.webp

It looks like the terminal screw may have been the original point of failure and heat generation.

upload_2021-8-4_15-57-33.webp

I’ve brushed and buffed the pin. May revisit with brasso or a lapping compound.

After 5 kWh charging, my fingers found uniform temperature. Once I find my IR thermometer, I’ll retest at night.

The replacement:
upload_2021-8-4_16-4-36.webp

No maker identified.

Bob Wilson
 
bwilson4web said:
Here is the failed plug:
View attachment 13006
It looks like the terminal screw may have been the original point of failure and heat generation.

View attachment 13007
I’ve brushed and buffed the pin. May revisit with brasso or a lapping compound.

After 5 kWh charging, my fingers found uniform temperature. Once I find my IR thermometer, I’ll retest at night.

The replacement:
View attachment 13008
No maker identified.

Bob Wilson
Click to expand...
index.php

The male cord cap should be replaced as the heat has probably melted the insulation around the conductor within the connector body itself. It may operate for some time with cleaned contacts , but the original problem of the termination within the female receptacle loosening transferred that heat to the male cord cap as shown in your picture remains.
The cost is minimum to replace and I would recommend it. I have seen many occurrences of this over the years and always change the male connector as part of the repair process, whatever equipment it may be supplying.;)
 
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After a screw is tightened down on copper, the copper tends to "creep" and make things just
a little looser. When tightening fittings like that I always hold the final torque for a while longer,
and it usually snugs down a little more in the process. Wiggling tne wire if possible and giving
every screw one more little squeeze before buttoning things up is a good idea.

Also note how the female spring contacts in several of these aren't full blade height...

_H*
 
hobbit said:
...
Also note how the female spring contacts in several of these aren't full blade height...
Click to expand...
Yea, I saw that too. Another finger temperature test and after 8 kWh, no discernible temperature problem. Happily, found my IR temperature tool that needs a new battery.

I spoke with 'management' about my testing and suggested their facilities guy needs to re-torque the wire clamps in a month. I suspect that will be enough to last at least six years or longer.

Bob Wilson
 
How frequently does the plug gets in and out the receptacle as they might not be designed for this kind of service use?
Is this installed at your workplace with frequent in-outs?
Do you have to bring your own EVSE and take it out after use?
If so, are the other EVSE plugs corroded?
Compare with the designed maximum number of insertions directly from the supplier or specs sheet. This number of plug-in, plug-outs is much lower than people think and the same problem is frequent with L1 120 V EVSE « emergency unit » that comes with the car.
The one given with Rav4 Prime even has a built-in counter to give a «replace EVSE» alarm to minimize overheating like you got.
That is the main reason to wire permanently in the supply cable and not use a convenience plug-receptacle system.

Sent from my iPhone using Inside EVs
 
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The NEMA 14-50 is in a locked, external box and plugged into the same Juicebox 40 Pro for 6 years. Once we check for ‘infantile’ problems, it will remain locked up.

The Juicebox handles:
  • 7 AM to 11 PM service
  • 8 kWh charge limit, $.88
  • Recording usage
I’m the admin who donated, operates the EVSE, and coordination.

Bob Wilson
 
Fastnf said:
You also might consider replacing it with a industrial version. Commercial receptacles may not handle high current draw for sustained periods of time as well. If you got the receptacle from a local big box hardware store you can probably assume it's commercial not industrial grade. An electrical supply house will have the larger industrial version. They are physically larger in diameter. View attachment 13000

Cooper/Eaton 5745N or Hubbell HBL9450A are examples the industrial receptacles. An Industrial grade outlet will have a larger face which requires a receptacle cover with a 2.48" ID hole. (Mulberry 97223)

They are also considerably more expensive.
Click to expand...

Leviton finally gets on board with a new heavy duty 14-50 receptacle industrial grade and specifically designed for electric vehicle charging. It has a picture of an EV on it so not hard to mistake, also available in weather resistant version.
Pressure wire terminal connections rated 75 inch/lbs up to #4 AWG, c/w heavy gauge high performance copper contacts.
I would have no issues installing one of these if required.
1450R-and-1450W_2_large.jpg

50 Amp EV Charging Receptacle/Outlet, Heavy Duty, 1450R – Leviton
 
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I've asked for their technical specs and dimensions. It looks like I would have to trim some of the mounting plate and drill two holes fit in the same, outdoor housing I'm using today.

Bob Wilson
 
Having acquired a second phev, I'm finally looking to install L2 and came across the Leviton offering. They state that GFCI is required for the WR version, so I'm staying away from that one based on user reports of nuisance trips from independent GFCI (and other user reports that 2023 NEC allows the GFCI functionality to be provided by the EVSE). Here's the info page with links to pdfs:
https://www.leviton.com/en/products/1450r
 
Steven B said:
Having acquired a second phev, I'm finally looking to install L2 and came across the Leviton offering. They state that GFCI is required for the WR version, so I'm staying away from that one based on user reports of nuisance trips from independent GFCI (and other user reports that 2023 NEC allows the GFCI functionality to be provided by the EVSE). Here's the info page with links to pdfs:
https://www.leviton.com/en/products/1450r
Click to expand...
The latest National Electrical Code requires a GFI breaker if you use a plug/receptacle. Not every jurisdiction follows the latest National Electric Code, so whether a GFI breaker is required depends on where you live. You can always hardwire your EVSE, and that doesn't require a GFI breaker to meet the National Electrical Code.

I suspect the GFI requirement has less to due with just an EVSE, and more likely due to the receptacle being available to any other device to could get plugged into the receptacle, hence an EVSE doesn't need a GIF breaker for a hardwired EVSE.

You can read the National Electrical Code for free if you sign up for a free account.

https://www.nfpa.org/codes-and-standards/7/0/70?l=109
 
This is not the first report of this I have seen online. I believe the issues is in fact residential quality parts used continuously at the full load. NEMA 14-50 may be rated for 50 amps FLA, but the service is only 40 amps. The chargers know this of course.

I use a 14-30 (dryer) plug which is rated for 24 amps of service. However I dial down the charger to 20 amps for additional safety as I charge overnight. For what it is worth, I would say if you don't need the speed of 40 amps (I don't), I would lower the draw. You can always amp it up if your in a hurry.
25 amps is about 22 miles of charge per hour - plenty for an overnight charge.
 
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