Also had some people say that you can use six awg. But that's not recommended:
I always install these with 4 awg unless it's on the concrete wall of the bunker. Better safe than sorry.
Fire risk of common NEMA 14-50 outlets
- Thread starter Will Prowse
- Start date
Also had some people say that you can use six awg. But that's not recommended:
I always install these with 4 awg unless it's on the concrete wall of the bunker. Better safe than sorry.
For continuous duty and max current carrying capacity, use the largest conductor recommended for the terminal.
Mike 134
Solar Enthusiast
or you could make the connections properly to the device then #6 would be fine
Tulex
Solar Wizard
This is the type of video that can really make a difference in someone's life. Awesome.
Then why are the manuals recommending 4 awg? With proper connections.
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JohnGyver
Solar Enthusiast
I wired mine with 6-gauge THHN for a 40-foot run for my EV charger outlet. That was to spec. We have two EV's... a Ford lightning and a Nissan Ariya and have been charging both for 1 year now. My 14-50 outlet is a heavy-duty model that has an Emporia Stage 2 EV charger plugged into it, note that it is set internally to only operate at 40A on a 50A rated outlet. The wire run is underground to a metal RV cover, all outside away from anything flammable. After 1 year of use on 2 EV's it hasn't shown any issues. I did inspect the inside about 6 months in with no noticeable concerns from that inspection.
I did watch a YouTube video (several actually) a year ago about using the cheapo dryer plugs on EV chargers... and that is a NO-NO. You need to get an outlet that is beefy and rated for continuous use, especially when using for EV charging.
Love all of your hard work and video's Will! Thank you for leading the charge!
Best regards,
John
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If it's set to 40A you're good with 6awg. And thank you!
chill633
Solar Enthusiast
Technically, according to NEC 110.3(B), you need to follow manufacturers instructions. The more restrictive wins, so if wiring amp tables say #6 and Tesla manual says #4, code says you need #4. (Doesn't work in reverse.)
BigGun
Solar Enthusiast
I wonder if the thin Molded male plug terminals is contributing to the heat. The add on male plugs have a heavy Brass blade.
I've seen this kind of thing with regular outlets. People plug big compressors and golf cart chargers in 99cent outlets.
I've seen this kind of thing with regular outlets. People plug big compressors and golf cart chargers in 99cent outlets.
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Horsefly
Solar Wizard
I'm glad you did this @Will Prowse. As I was planning where to be able to plug in my Tesla Mobile charger I decided to guy my own 14-50 socket rather than have the electrician do it. I was about to pull the trigger on the cheaper one and then saw some of the reviews that pointed out the same thing you are reporting. I ended up spending a little more for the Hubble socket.
One other thing that may be worth mentioning: I read that even the best of the 14-50 sockets are not intended to support frequent plugging and unplugging of the 14-50 plug into the socket. I don't know that it is really an issue, but I tend to leave it alone (unless I'm taking the mobile charger with me on a long trip).
One other thing that may be worth mentioning: I read that even the best of the 14-50 sockets are not intended to support frequent plugging and unplugging of the 14-50 plug into the socket. I don't know that it is really an issue, but I tend to leave it alone (unless I'm taking the mobile charger with me on a long trip).
seneysolar
24V
Im confused, how did the wire size become an issue? Its the receptacle that melts, not the wires correct? Where the blades of the plug make contact. Sounds like its an issue with the contact surface. Too small or oxidation will will make for poor connection and get hot.
Normally 6ga THHN has an ampacity of 75A and could be installed on a 50A and still meet code. The inspector doesn't know what brand charger you are going to plug into it. The receptacle, wire and breaker should all be 50A capable.
What size cord comes on these EV chargers? Has anyone cut one off to see what they use? It doesn't look any bigger than 6ga SOOW.
Ive never installed an ev charger, just curious.
Normally 6ga THHN has an ampacity of 75A and could be installed on a 50A and still meet code. The inspector doesn't know what brand charger you are going to plug into it. The receptacle, wire and breaker should all be 50A capable.
What size cord comes on these EV chargers? Has anyone cut one off to see what they use? It doesn't look any bigger than 6ga SOOW.
Ive never installed an ev charger, just curious.
sunshine_eggo
Victron's little biatch
Hmmm... @sunshine_eggo wonders about his NEMA 14-50 installation with 6awg direct bury that powers all of HBR... 
It's never been called upon for 50A, but it has tickled ~40A several times.
It's never been called upon for 50A, but it has tickled ~40A several times.
6 AWG works great for continuous 40A.
Need 4 AWG if you are pulling 50A Continuous. Most manuals state that even with 4 AWG, you can only use 40A with a plug between the charger and breaker.
Need hardwire 4 AWG to pull 50A all day long without issue.
Need 4 AWG if you are pulling 50A Continuous. Most manuals state that even with 4 AWG, you can only use 40A with a plug between the charger and breaker.
Need hardwire 4 AWG to pull 50A all day long without issue.
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You can't pull 50A continuous through a NEMA 14-50. That's why chargers that are made to plug into them top out at 40A. 48A chargers need to be hard wired to a 60A circuit.
Also you only actually need 8 AWG copper THHN for a NEMA 14-50 plug (although I'd typically use 6 AWG anyways). Anything 8 AWG and larger can use the 75C ampacity column as long as both wire and terminations support it.
Yes agreed, but I have found that the industrial rated Hubbell is rated for continuous 50A. But as I said above, the manuals for the chargers say that 40A is maximum. Thought I should mention both.
chill633
Solar Enthusiast
This. People forget the 120% rule where the components of a circuit need to support 120% of the rated load. A 40A device needs 48A wire, receptacle, and breaker. Since they don't make 48A parts you need to step up to 50A.
For 48A loads you need to support 57A, so step up to 60A wire and breakers. That's also why you can't use UF4-3 because it is 60° C cable and only rated for 55A, not 60A like THHN #6.
You'd have to hook it up to a 50A continuous rated breaker too which isn't standard for residential panel breakers
fatjay
Solar Wizard
NEMA 14-50 is the same plug on my 10kw generator off amazon. I plug a male into it which then goes to a CS364 plug, and a receptacle which then is wired into my breaker box with a 50a dp breaker. The other day I had to use my generator for the first time with my solar to power my inverters and charge my batteries.
While the plug says 50a on the generator, the generators main breaker tripped when I pulled more than 6000w, which is 25a per leg. Which is exactly what @Will Prowse said he had to lower it to so that the temp sensor didn't kick on.
So it seems my 10k genset isn't really 10k, but rather 6k continuous. The inverters also did not like the phases and complained with a beep every second, but they did take it, and the batteries did charge and it supplied the house.
This is the generator in question, if anyone is curious.
While the plug says 50a on the generator, the generators main breaker tripped when I pulled more than 6000w, which is 25a per leg. Which is exactly what @Will Prowse said he had to lower it to so that the temp sensor didn't kick on.
So it seems my 10k genset isn't really 10k, but rather 6k continuous. The inverters also did not like the phases and complained with a beep every second, but they did take it, and the batteries did charge and it supplied the house.
This is the generator in question, if anyone is curious.
Theres a lot of details improperly cited in here.
First of all, there is the wall connector and the mobile connector.
Wall connectors - G3 is rated to 48A max. 125% rule needs 60A breakers. 6awg is fine if breakers are 75C. 4awg if on 60C breakers.
Gen 1 and gen 2 wall connectors are up to 80A. 125% is 100A breakers. 3awg.
Mobile connectors max is 40A, 125% is 50A breakers.. 6awg all day long.
Im on mobile so can't cite the whitpapers, but anyone can go to tesla and download each data spec.
Tesla makes no rcommendation re 4vwg or 6awg, defers to local codes.
Best tobsupport the mobile charger cord , it's not good to have the plug move at all. Theres an insertion cycle count rating.
I have gen 2 wall connector at 32 amps, = 40amp breaker. Also redid all the wiring up and down my neighborhood for free. Always 6awg at 48A max (Wall Connector) and always Hubbell brands Edit to add: for the mobile 14-50.
First of all, there is the wall connector and the mobile connector.
Wall connectors - G3 is rated to 48A max. 125% rule needs 60A breakers. 6awg is fine if breakers are 75C. 4awg if on 60C breakers.
Gen 1 and gen 2 wall connectors are up to 80A. 125% is 100A breakers. 3awg.
Mobile connectors max is 40A, 125% is 50A breakers.. 6awg all day long.
Im on mobile so can't cite the whitpapers, but anyone can go to tesla and download each data spec.
Tesla makes no rcommendation re 4vwg or 6awg, defers to local codes.
Best tobsupport the mobile charger cord , it's not good to have the plug move at all. Theres an insertion cycle count rating.
I have gen 2 wall connector at 32 amps, = 40amp breaker. Also redid all the wiring up and down my neighborhood for free. Always 6awg at 48A max (Wall Connector) and always Hubbell brands Edit to add: for the mobile 14-50.
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Now that's a good forum post. Nice. Good points.
When I installed my Tesla hardwire Universal Wall a charger last year, 6awg thhn was recommended. The wires and EMT get warm but never hot to the touch at 48amps with 60amp breaker.
In the process of installing one at our cabin, still with 6awg thhn but may drop down to 40amp with 50amp breaker due to the 80ft run of wire.
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zanydroid
Solar Wizard
I want to point out that a lot of hardwired EVSE that top out at 48A only accept 6AWG.
Tesla is pretty special in accepting 4AWG on a 48A EVSE.
Also speaking to why the wire matters. The bigger the wire, the lower the resistive heating per unit length of wire. Which means the device or receptacle connected to the wire sees a lower temperature.
(A bigger wire also has more surface area to dump out the heat, which will help a little too)
Tesla is pretty special in accepting 4AWG on a 48A EVSE.
Also speaking to why the wire matters. The bigger the wire, the lower the resistive heating per unit length of wire. Which means the device or receptacle connected to the wire sees a lower temperature.
(A bigger wire also has more surface area to dump out the heat, which will help a little too)
I'm using one of those cheap-o 14-50 outlets that Will cited in his video. While I don't think the outlet is my only problem, I'm going to replace it.
My 2019 Nissan Leaf SV+ will supposedly draw no more than 30 amps. 6.6kW / 240v = 27.5 amps. Wire gauge calculators said I could get by with 8 gauge for the distance. The outlet is getting warm. The EVSE plug has a sensor in it that detects the temperature. Mine has gone into fault mode due to high temperatures a couple of times. I'll start by replacing the outlet and then stepping up to 6 gauge wire.
My 2019 Nissan Leaf SV+ will supposedly draw no more than 30 amps. 6.6kW / 240v = 27.5 amps. Wire gauge calculators said I could get by with 8 gauge for the distance. The outlet is getting warm. The EVSE plug has a sensor in it that detects the temperature. Mine has gone into fault mode due to high temperatures a couple of times. I'll start by replacing the outlet and then stepping up to 6 gauge wire.
If 30A, 8awg is really ok. The receptacle contacts on those cheap 14-50s are far inferior too. Then if one is using a mobile type plug that gets plugged in/out at various locations, the plug eventually gets fouled and is then introduced to the home receptacle.
Keeping those contacts (plug and receptacle) clean is paramount to safe, long term operation.
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