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NEMA 14-50 Supply cable heat data

daveo4EV

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Hello,

my Taycan has been charging at 40 amps for over 2 hours this morning at roughly 64 degrees ambient temperature. I gathered the following data from various points in the charging circuit:

all measurements are on Fahrenheit:

I think the NEMA 14-50 cable is getting too hot - probably due to inappropriate wire gauge - the label says rated for 16 amps - and thickness is appropriate for 16 amps - I'm betting they didn't do the proper gauge for North America, and instead are working European standards - 3 phase 16 amp rated wire - but what do I know.

the supply Cable from the sub-panel is less than 90F - and the breaker itself is less than 90F - but the Porsche provided supply cable is running 2x temp vs. the rest of the system - something seems wrong.

the temperature of the J-1772 cable and the J-1772 Plug are below 90F - so no issues there.

Temp Measurements Porsche Charger.jpg
 
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I've sent an eMail to my Sale Manager asking for Porsche's opinion on my data. Given the potential implications of such a letter - I do not expect a rapid response - but will share what ever they share with me.
 
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here is the label from the Supply Cable…

Porsche NEMA 14-50 Supply Cable Label.jpg
 

wmras

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Hello,

my Taycan has been charging at 40 amps for over 2 hours this morning at roughly 64 degrees ambient temperature. I gathered the following data from various points in the charging circuit:

all measurements are on Fahrenheit:

I think the NEMA 14-50 cable is getting too hot - probably due to inappropriate wire gauge - the label says rated for 16 amps - and thickness is appropriate for 16 amps - I'm betting they didn't do the proper gauge for North America, and instead are working European standards - 3 phase 16 amp rated wire - but what do I know.

the supply Cable from the sub-panel is less than 90F - and the breaker itself is less than 90F - but the Porsche provided supply cable is running 2x temp vs. the rest of the system - something seems wrong.

the temperature of the J-1772 cable and the J-1772 Plug are below 90F - so no issues there.
Purchased a 6-30 supply cable from Porsche parts. It may have the same supply cable as your 14-50 unit. The 6-30 input cable is embossed #10AWG (appropriate for a 30 amp circuit), but the tag is labeled 16A maximum. However, the cable assembly is labeled 24A (appropriate for a 30A circuit). Left hand not in sync with right hand, but this 30A supply cable is probably fine and safe.

If your 50A 14-50 is the same wire size (#10AWG), it is not properly rated unless they are depending on the high-temperature rating of the short 12" wire.

In general, European standards for wire size are larger than US sizes for the same current rating. My data point is old, but the US has a higher electrical fire accident rate than Europe because of wire size, and Europe has a higher accident rate by electrocution because of 240V. Choose your poison.
 
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does anyone have an opinions as to the surface temperatures I measured? Ambient air temp was less than 68F - so imagine what these surface temps would be at say 95F on a hot summer day…

is 144F acceptable as a surface temperature for a NEMA 14-50 plug?

is this nothing to worry about?
 
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does anyone have an opinions as to the surface temperatures I measured? Ambient air temp was less than 68F - so imagine what these surface temps would be at say 95F on a hot summer day…

is 144F acceptable as a surface temperature for a NEMA 14-50 plug?

is this nothing to worry about?
I will soon. My car and charger have been at Porsche since last Thursday for this specific issue (the temperatures, not the labeling). I have asked them to give me a copy of their temperature tests so that I can compare them to what I get at home. I'm not home so I can't give my home readings but will update later.

According to Porsche in consultation with the dealer, the temp readings they were getting at the service dept are within expected limits but to me they seem high. They said they also took another Taycan they had and did the same with that one and they said the 2 cars were getting very similar temperature readings. So Porsche is basically putting it back to me to deal with my electrical setup.

I had my dealership's electrician come to my house to check my installer's wiring and the only thing he would like to see redone is the wiring in the receptacle box. The wires were pushed in tight and bent causing resistance. He suggests installing an extension on the box to bring the receptacle and wiring out more from the wall. This is so that only 90 degree bends in the wire in the receptacle are achieved rather than multiple bends in a tight space causing resistance and overheating.

To be continued . . .
 
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wmras

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does anyone have an opinions as to the surface temperatures I measured? Ambient air temp was less than 68F - so imagine what these surface temps would be at say 95F on a hot summer day…

is 144F acceptable as a surface temperature for a NEMA 14-50 plug?

is this nothing to worry about?
What was the current draw when you made the temperature measurements?

The Porsche supply cable at 162F (72C) is the hottest measurement shown. The cable is rated for 105C (221F) so you are 33C (91F) away from the cable rating. 68F + 91F (159F) is a very hot day, so technically safe. However, if the Porsche Supply cable is #10AWG like the 6-30 cable, US code would limit the continuous draw to 24A (80% of 30A). If the Porsche Supply Cable is #10AWG, consider using it up to 30A because it is a system component and rated for 105C (my choice).
 

wmras

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I had my dealership's electrician come to my house to check my installer's wiring and the only thing he would like to see redone is the wiring in the receptacle box. The wires were pushed in tight and bent causing resistance. He suggests installing an extension on the box to bring the receptacle and wiring out more from the wall. This is so that only 90 degree bends in the wire in the receptacle are achieved rather than multiple bends in a tight space causing resistance and overheating.

To be continued . . .
+1 Also consider using an industrial grade receptacle like a Hubbell HBL9450A, which will need the faceplate extension.
 
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current draw reported by the PMCC was 39.4 AMPs…
 

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does anyone have an opinions as to the surface temperatures I measured? Ambient air temp was less than 68F - so imagine what these surface temps would be at say 95F on a hot summer day…

is 144F acceptable as a surface temperature for a NEMA 14-50 plug?

is this nothing to worry about?
Not apples to apple just as a form on information I just went into my garage to take a heat reading of my Charge Point its been plugged in 1.5 hours charging my Kona. The readings I got 83.4 at the wall plug and 81.1 on the cable with a reading of 83 on the charge cable to the car
 

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current draw reported by the PMCC was 39.4 AMPs…
Im not an electrician and I might be wrong but I thought when using a plug in rather than a hard wired connection from breaker to a wall charger the AMPs need to be set to 32AMPS for the plug version it can go to 40AMP when hard wired
 
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NEMA 14-50 plugs are a 50 amp circuit (50 amp breaker) but need to be discounted 20% for "continuous" use devices like an EVSE…

NEMA 14-50 plugs are also allowed to be used with a 40 amp breaker which would require 32 amp max continuous Current draw.

40 amps is the correct current draw for a NEMA 14-50 circuit and exactly matches Porsche's charging specifications for the Taycan and their charger at 9,600 watts.

240 volts * 40 amps = 9,600 watts (240*40)
 
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numbers are no higher at th 5 hour mark - so while they are high - things are stable - numbers are also no lower - I've measured the surface temperature of each "segment" of the system - and the only segment that is abnormally warm is the NEMA 14-50 supply cable - all other elements are 90F or less.
 

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Hello,

my Taycan has been charging at 40 amps for over 2 hours this morning at roughly 64 degrees ambient temperature. I gathered the following data from various points in the charging circuit:

all measurements are on Fahrenheit:

I think the NEMA 14-50 cable is getting too hot - probably due to inappropriate wire gauge - the label says rated for 16 amps - and thickness is appropriate for 16 amps - I'm betting they didn't do the proper gauge for North America, and instead are working European standards - 3 phase 16 amp rated wire - but what do I know.

the supply Cable from the sub-panel is less than 90F - and the breaker itself is less than 90F - but the Porsche provided supply cable is running 2x temp vs. the rest of the system - something seems wrong.

the temperature of the J-1772 cable and the J-1772 Plug are below 90F - so no issues there.

Temp Measurements Porsche Charger.jpg
Many of us are having the same issues. As wmras has accurately pointed out in other posts regarding this issue there are a few factors that contribute to the unusually high temps on the receptacle and 14-50plug and cable. Mine, I believe, has to do with having the wrong gauge wire (6 gauge) from the breaker 70 feet away. Bill is extremely knowledgeable all-things electrical and recommended using a 4 gauge wire for anything longer than 50 feet. My electrician ordered it today and will install next week. Why I think this may be the answer was by process of elimination: changed receptacle (not a Hubell), and exchanged the charger with another one from an unsold Taycan from dealer. Even had heat issues after dialing down from 40A to 32A and still felt 90% of the heat compared to the 40A. Today I went down to 24A for sh*ts and giggles and everything seemed normal and much cooler ie; receptacle, plug and cable. Even the the car’s cable was hardly warm. So, I think there are other individual factors, such as yours, influencing this heat issue and unfortunately Porsche, unlike Bill, still does not have a full handle on how and what to check for RE home charging. After all I went through Porsche said “there’s something wrong with the wiring in your house”. They are correct, I believe, but it would’ve been nice to recommend certain protocols PRIOR to engaging my electrician and saving me an additional $600 out of pocket now. My electrician spoke to Porsche early on about this issue and he was told to use a 6 gauge wire after being told the wire would be 70 feet. Originally had an 8 gauge wire along with a 14-30 plug (exchanged for 14-50) that the dealer was erroneously told last year to order for all their Taycans by Porsche!!!!!

Perhaps COVID-19 played a role in not getting the proper training to the dealers as Taycans were being delivered just a couple of months ago, when we got our
4S, and Porsche restricted their corporate trainers from physically going to dealers for refresh training....understandable.

Many thanks to Bill and members of this Forum. Hope the 4 gauge does the trick!!!
 

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