NEMA 14-50 plug is dangerously hot!!

[mod72346]

I have a standard Porsche charger (w/o LED display) and I've been using it a few times to charge at at home. I have two questions:

- The circuit is 50A, but the maximum charging power I've seen is only 8.67 kW, or ~36A - why is it not at least 40A?

- The NEMA 14-50 plug gets extremely hot - can't hold touching it, it's burning. There are similar threads about this (e.g. https://www.taycanforum.com/forum/threads/nema-14-50-supply-cable-heat-data.1940/) that seem to blame the short NEMA 14-50 cable, which does get quite hot too. So, I bought a thermal camera and took a look today. To my surprise, the problem is not with the outlet - the hot spots are clearly on both sides of the plug INSIDE THE PLASTIC where the two phases are. This is really concerning. After ~20 min of charging, the plug temperature reached 80C or 176F -- which I think is dangerous, and it's not even at full amperage. What's going on? Is the cable defective? Should I take it to Porsche? What do I tell them?

Please help.

See two photos attached with the plug, which I took out of the electrical box to troubleshoot the heating issue, and the thermal image, which indicates that the hottest spot is on the side of the plug.

BTW, it's Hubbell.

UPDATE: After running for 45 min, the plug hotspot reached 88.2 C (or 190 F):

 

[Windpower]

It’s good that you have a thermal camera so you know where the hot spot is. From the thermal picture, the hot spot is inside the PMC+ 14-50 connector which most likely is defective.

The heat comes from a higher than normal resistance inside the plug, most likely caused by a defective connection between the cable wire and one of the cable connector pins. Higher resistance creates heat and will drop the voltage going into your car, lowering the charge rate. A properly manufactured connector will have very little resistance between the wire and the pin and will not generate any excess heat.

I would immediately do two things:
- call your dealer, report the problem and have them send you a new 14-50 PMC+ cable
- dial down the PMC+ charge rate to 50% until you get the new cable. This will lower the current going through the defective connector and will lower the temperature. Check the temperature again with the 1/2 current and see how it looks.

As it is, the extreme temperature is not good. You should be able to touch the connector while charging. When it gets too hot, it indicates a problem which is a safety issue.

 

[RAHRCR]

I have a standard Porsche charger (w/o LED display) and I've been using it a few times to charge at at home. I have two questions:

- The circuit is 50A, but the maximum charging power I've seen is only 8.67 kW, or ~36A - why is it not at least 40A?

- The NEMA 14-50 plug gets extremely hot - can't hold touching it, it's burning. There are similar threads about this (e.g. https://www.taycanforum.com/forum/threads/nema-14-50-supply-cable-heat-data.1940/) that seem to blame the short NEMA 14-50 cable, which does get quite hot too. So, I bought a thermal camera and took a look today. To my surprise, the problem is not with the outlet - the hot spots are clearly on both sides of the plug INSIDE THE PLASTIC where the two phases are. This is really concerning. After ~20 min of charging, the plug temperature reached 80C or 176F -- which I think is dangerous, and it's not even at full amperage. What's going on? Is the cable defective? Should I take it to Porsche? What do I tell them?

Please help.

See two photos attached with the plug, which I took out of the electrical box to troubleshoot the heating issue, and the thermal image, which indicates that the hottest spot is on the side of the plug.

What brand of outlet do you have and was it professionally installed?

 

[daveo4EV]

this is a known issue

https://www.taycanforum.com/forum/threads/nema-14-50-supply-cable-heat-data.1940/

the PMCC/PMC+ is a terrible EVSE - VW/Audi/Porsche cheaped out on the wire gauge inside the NEMA 14-50/6-50 supply cable - they use 10 gauge wire vs. 8 or 6 gauge wire which would've been a better choice.

if you escalate this to Porsche you'll eventually get a response to dial down the AMPs to lower than 40 amps to "resolve" the issue.

this has been extensively discussed in other threads.

the only solution to date is purchase a better and most cost effective EVSE - VW/Audi/Porsche's charger for North America is substandard in my opinion - there are way way way better choices.

 

[daveo4EV]

I have a standard Porsche charger (w/o LED display) and I've been using it a few times to charge at at home. I have two questions:

- The circuit is 50A, but the maximum charging power I've seen is only 8.67 kW, or ~36A - why is it not at least 40A?

- The NEMA 14-50 plug gets extremely hot - can't hold touching it, it's burning. There are similar threads about this (e.g. https://www.taycanforum.com/forum/threads/nema-14-50-supply-cable-heat-data.1940/) that seem to blame the short NEMA 14-50 cable, which does get quite hot too. So, I bought a thermal camera and took a look today. To my surprise, the problem is not with the outlet - the hot spots are clearly on both sides of the plug INSIDE THE PLASTIC where the two phases are. This is really concerning. After ~20 min of charging, the plug temperature reached 80C or 176F -- which I think is dangerous, and it's not even at full amperage. What's going on? Is the cable defective? Should I take it to Porsche? What do I tell them?

Please help.

See two photos attached with the plug, which I took out of the electrical box to troubleshoot the heating issue, and the thermal image, which indicates that the hottest spot is on the side of the plug.

your heat data shows the hotest temps inside the supply cable - this heat is transfering back to the NEMA 14-50 plug/socket - this is expected given how hot the cable is getting.

the problem is the 10-gauge wire inside the supply cable.

you can upgrade to a better 14-50 plug - Hubble Comercial/industry sockets are higherly quality and may do better - but as long the the PMC+/PMCC get hot you can expect the socket they are plugged into to get hot.

the temperatures while hot at not "un-safe" - just uncomfortable for a mobile charger which is meant to be handled by humans.

I recommend moving on and giving up on the PMC+/PMCC if this concerns you - there are many many many many alternatives that are higherly quality and lower cost than the VW/Audi/Porsche PMC+/PMCC…

you can solve this problem for way less than $500 by simply purchasing an alternative EVSE…

VW/Audi/Porsche screwed this one up in their design of the supple cable - and they have yet to improve the situation and seem unconcerned.

upgrade the NEMA socket to a Hubble model
purchase an alterantive EVSE (either mobile) or wall mounted.

 

[daveo4EV]

I have a standard Porsche charger (w/o LED display) and I've been using it a few times to charge at at home. I have two questions:

- The circuit is 50A, but the maximum charging power I've seen is only 8.67 kW, or ~36A - why is it not at least 40A?

- The NEMA 14-50 plug gets extremely hot - can't hold touching it, it's burning. There are similar threads about this (e.g. https://www.taycanforum.com/forum/threads/nema-14-50-supply-cable-heat-data.1940/) that seem to blame the short NEMA 14-50 cable, which does get quite hot too. So, I bought a thermal camera and took a look today. To my surprise, the problem is not with the outlet - the hot spots are clearly on both sides of the plug INSIDE THE PLASTIC where the two phases are. This is really concerning. After ~20 min of charging, the plug temperature reached 80C or 176F -- which I think is dangerous, and it's not even at full amperage. What's going on? Is the cable defective? Should I take it to Porsche? What do I tell them?

Please help.

See two photos attached with the plug, which I took out of the electrical box to troubleshoot the heating issue, and the thermal image, which indicates that the hottest spot is on the side of the plug.

most electrical gear is rated for 90C/100C temps as "max" - your data shows 80.9C (81C) max inside the supply cable and far lower temps inside the NEMA 14-50 socket - there is nothing "unsafe" here other than handling the equippment shortly after charging…

again - get another charger and be happy.

all porsche is going to tell you to do is lower the AMPs - either via the 50% button on the PMC+ or via the LCD screen on the PMCC - they have _NO FIX_ - this is what happens when you use 240V/40 amps with 10-gauge wire - it in fact 100% matches the predicted temperature tables for 10 gauge wire @ 240V/40 amps…it is behaving as designed - and is not unsafe - just uncomfortable.

the only solution so far is:

• dial down the amps - this is the official Porsche response to date…
• purchase an alternative EVSE from an alternate vendor.

yeah it sucks - but that's where we are at.

 

[daveo4EV]

https://www.taycanforum.com/forum/t...e-charger-plus-for-wallbox-pulsar-plus.11822/
https://www.taycanforum.com/forum/threads/any-reason-to-get-an-aftermarket-charger.11755/
https://www.taycanforum.com/forum/t...-charging-my-tesla-model-y-long-range….10941/
https://www.taycanforum.com/forum/threads/ditch-the-pmcc-for-now.1996/
https://www.taycanforum.com/forum/threads/porsche-wall-charger-connect-error.8205/

a lot of customers are disappointed with the PMC+/PMCC

 

[daveo4EV]

which I think is dangerous, and it's not even at full amperage. What's going on? Is the cable defective? Should I take it to Porsche? What do I tell them?

not defective - behaving as fore-seeable from nearly a century of electrical engineering given the decision to use 10-gauge wire inside the 14-50 supply cable - an electrically safe, but awkward choice for "mobile" EVSE meant to be handled by humans - a new cable with 10-gauge wire will behave exactly in the same manner - so unless the design gives you a new design with new part number (which to date does not exist) I would expect the exact same behavior across all possible NEMA 14-50 supply cables from VW/Audi/Porsche

it's not unsafe electrically unless it would get hot enough to "melt" the insulation and potentially cause a short - and while it's clearly too hot to comfortably handle with bare hands it's not hot enough to "fail" the insulation or jacket of the supply cable…

this will remain this way until VW/Audi/Porsche decided to change the internal wire gauge to the supply cable to 8 or 6 gauge wire…

all you need to know is actually stamped/stenciled on the supple cable coating…

post #3 - see photo - https://www.taycanforum.com/forum/threads/nema-14-50-supply-cable-heat-data.1940/#post-25636
post #25 - see data at different amps - https://www.taycanforum.com/forum/threads/nema-14-50-supply-cable-heat-data.1940/page-2#post-25707
post #37 - see text & photo - https://www.taycanforum.com/forum/threads/nema-14-50-supply-cable-heat-data.1940/page-3#post-26318

also the cable would not be considered "unsafe electrically" unless the temps achieved would cause the surrounding jacket/insulation to fail - and there are a variety of materials one could choose with various melt-ing points - hypothetically you could allow wires to get to 130-150C internal temps _IF_ one were to choose an appropriate coating/insulation/jacket enclosing the wiring - again this is a hypothetical example…it is clear porsche chose 10-gauge wire - what is less clear is the quality of the jacket/insulation/coating and the particulars of the materials they have used to safely enclose the wires - and I know next to nothing about materials design so I can not even remotely speculate. But I'm going to spot VW/Audi/Porsche know what they're doing here and make good/excellent choices on the supply cable coating/jacket/insulation - so while the cable gets hot by human standards - I highly doubt it's even close to causing a problem for the cable's materials - it's probably way over designed from a close-failure point of view…

just because it's too hot to handle doesn't mean it's unsafe or close to failure…and this is the grey area in which Porsche is currently living - they have a safe cable, but it's uncomfortable to use.

the cable is behaving with in expectations given the design choices…but is with in specification for being electrically "safe" - but it _IS_ uncomfortable for human handling during charging given the observed/expected heat rise due to the use of 10-gauge wire…

it is a fact that the current NEMA 6-50/14-50 supply cable gets very very warm to human touch - it is also a fact that it may be too hot to handle with bare hands - but it can be BOTH of those things and more - and still be electrically "safe" in that the cable will not fail/melt/short given the design of the materials - and in particular the choice of insulating materials VW/Audi/Porsche have chosen…

it's a bad design for a mobile charger, but to date Porsche has not felt the need to recall it/re-design it - and it does skate by as electrically "safe" in that it probably won't fail due to the thermals because it's a total package designed for the load/wire-gauge/insulation/temperature-extremes - it's a terrible design choice to choose 10-gauge wire for something that will be handled by bare hands since it's a mobile device meant to be handled, moved, packed…

 

[mod72346]

What brand of outlet do you have and was it professionally installed?

It's Hubbell, self install.

 

[mod72346]

your heat data shows the hotest temps inside the supply cable - this heat is transfering back to the NEMA 14-50 plug/socket - this is expected given how hot the cable is getting.

Dude, it's like you haven't read or seen anything from the original post.

 

[daveo4EV]

It's Hubbell

from the thermal image the 14-50 socket/receptical isn't actually that warm and is inline with expectations given the supply cable temp - the only problem I see on the thermal image is the crappy VW/Audi/Porsche supply cable NEMA 14-50P connector.

 

[mod72346]

this is a known issue

https://www.taycanforum.com/forum/threads/nema-14-50-supply-cable-heat-data.1940/

the PMCC/PMC+ is a terrible EVSE - VW/Audi/Porsche cheaped out on the wire gauge inside the NEMA 14-50/6-50 supply cable - they use 10 gauge wire vs. 8 or 6 gauge wire which would've been a better choice.

I've seen that thread.

It shows the high temp at the 14-50 plug and short cable, and it puts blame at the inadequate cable gauge. According to my thermal image, the hot spots are INSIDE THE PLUG - meaning, where the cable wires are attached to the blades - that's where the largest amount of heat is generated, and where the highest temperature is reached (exactly where you would grab the plug by hand - in the side grooves)

 

[RAHRCR]

It's Hubbell, self install.

The Hubbell is a pretty stout unit. We’re all the terminals torqued to spec?

 

[mod72346]

from the thermal image the 14-50 socket/receptical isn't actually that warm and is inline with expectations given the supply cable temp - the only problem I see on the thermal image is the crappy VW/Audi/Porsche supply cable NEMA 14-50P connector.

I think so. I wonder if the plug/connector can be cut and replaced... I can do a better job at that than Porsche.

Maybe something like this -- https://www.amazon.com/Camco-PowerGrip-Replacement-Transform-55255/dp/B000PGVZ30/ref=sr_1_6?crid=2W9NBBAFB12ML&keywords=NEMA+14-50+connector&qid=1658161715&sprefix=nema+14-50+connector,aps,123&sr=8-6

Or this -- https://www.amazon.com/dp/B086W8JHH...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

 

[mod72346]

The Hubbell is a pretty stout unit. We’re all the terminals torqued to spec?

Yes, I also checked with the thermal camera -- all parts of the receptacle are barely warm. The main source of heat is the plug assembly, and of course, the heat dissipates via blades into the receptacle, and the other direction toward the charger.

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