Very cool extension cord to have in case

[davewill]

The guy is wrong. He was pulling basically the same voltage before and after, the mph reading is prone to error from averaging and auxiliary usage, like the heater turning on.

Also, good reason to build your own. Temco soow 6/3 cable I got is light a flexible, even in cold weather. If I were doing it again, I'd go one more size down, save another few pounds. The UMC cable is tiny compared to this thing, it's overkill.

That's because the extension cord is built for 50a, but the Tesla cord is only built to carry 40a. You don't need a 50a extension cord. Once you're past the outlet, the 80% rule no longer applies. It's also more flexible because Tesla uses two smaller conductors instead of one large conductor for the current carrying legs.

 

[AWDtsla]

That's because the extension cord is built for 50a, but the Tesla cord is only built to carry 40a. You don't need a 50a extension cord. Once you're past the outlet, the 80% rule no longer applies. It's also more flexible because Tesla uses two smaller conductors instead of one large conductor for the current carrying legs.

No they are both built for 40A continuous. It's more flexible because Tesla chose much less total conductor per pole, despite using two wire per, as well as 1/3rd reduction because there is no neutral conductor.

The HPWC cable is the same gauge as this "50A extension", and it carries 80A continuous.

 

[davewill]

No they are both built for 40A continuous. It's more flexible because Tesla chose much less total conductor per pole, despite using two wire per, as well as 1/3rd reduction because there is no neutral conductor.

The HPWC cable is the same gauge as this "50A extension", and it carries 80A continuous.

I mentioned the two wire feature, but you're incorrect about the rating. The whole "continuous" requirement stops at the outlet. The Camco cord and the one from EVSEAdapters are both rated for 50a...which is more than is needed for 40a charging.

 

[hcsharp]

...Also, good reason to build your own. Temco soow 6/3 cable I got is light a flexible, even in cold weather. If I were doing it again, I'd go one more size down, save another few pounds. The UMC cable is tiny compared to this thing, it's overkill.

You should get SEOOW or SEOW cable for EV applications. It is rated for higher temperatures than the SOOW cable you got. It's also safer and capable of handling more current due to its higher thermal rating. If you're going to downsize the wires to save weight, you should go with SEOW rated cable.

The Campco cables are not always constructed very well. The cheap materials they use are partly to blame for how stiff it is when it's cold. I've seen some of them fall apart before they should.

 

[AWDtsla]

You should get SEOOW or SEOW cable for EV applications. It is rated for higher temperatures than the SOOW cable you got. It's also safer and capable of handling more current due to its higher thermal rating. If you're going to downsize the wires to save weight, you should go with SEOW rated cable.

Nah. There's pretty much no temperature rise charging at 40 amps for hours. I have to use an IR camera to notice any temperature difference at all. Like I said above, if doing it again, I'd get the same cable in 8/3.

 

[hcsharp]

Nah. There's pretty much no temperature rise charging at 40 amps for hours. I have to use an IR camera to notice any temperature difference at all. Like I said above, if doing it again, I'd get the same cable in 8/3.

In a perfect world nothing ever goes wrong. Nothing ever overheats. Nothing ever catches fire. But even if you do everything right sh*t still happens. There's a reason SE rated wire is specified for EV use. It's naive to think you are smarter than the scientists and engineers at UL and the board that writes the NEC.

A few years ago I would have agreed with you. I used SOOW cable for my first extension cord. I no longer use it. Since then I've heard a lot of scary stories. You need to be more careful than you think.

 

[AWDtsla]

In a perfect world nothing ever goes wrong. Nothing ever overheats. Nothing ever catches fire. But even if you do everything right sh*t still happens. There's a reason SE rated wire is specified for EV use. It's naive to think you are smarter than the scientists and engineers at UL and the board that writes the NEC.

A few years ago I would have agreed with you. I used SOOW cable for my first extension cord. I no longer use it. Since then I've heard a lot of scary stories. You need to be more careful than you think.

If you get anywhere near the 90C jacket rating of SOOW, you've got some serious problems that another 15C from SEOOW isn't buying you much. Also it's pretty easy not to expose it to the other conditions it was rated for, like oil, abrasion, and general abuse. IMHO it's more dangerous to try and unwind the cable above with it's 0F than to deal with my recommendation.

 

[Cottonwood]

Nah. There's pretty much no temperature rise charging at 40 amps for hours. I have to use an IR camera to notice any temperature difference at all. Like I said above, if doing it again, I'd get the same cable in 8/3.

I've done some experiments with 8/3 cable and 40 Amps. There is a noticeable, but acceptable temperature rise when the cable is laid out in an open pattern on the garage floor. The problem comes if you leave the cable coiled up. In that configuration, the runs of cable lay next to each other, and heat each other up. I did not do any calibrated measurements, but I considered the temperature rise unacceptable and dangerous with several loops in a coil.

If you do use 8/3 to carry 40 Amps, I strongly recommend that you use care and unroll coils completely. Also, check the cable and connections for unacceptable temperature rise, after connection, at 5, 15, and 30 minutes.

 

[marcad80]

I made this one, 70 feet. Good up to about 30 amps. Above that the car faults and limit amperage.

 

[AWDtsla]

I made this one, 70 feet. Good up to about 30 amps. Above that the car faults and limit amperage.

Depends on how stiff the supply is. Tesla told me the cutoff is 8% voltage drop from start of charge. I get about 3.5% drop just on the meter side at home.

 

[Firewired]

Spoke with EVSE Adapters. I like the fact that their 14-50 extension cord is lighter than the Camco, and offers the utility to plug in different plugs without having to mess with additional adapters. They are willing to make a 30' one. I'm waiting to get a price from them.

 

[marcad80]

Depends on how stiff the supply is. Tesla told me the cutoff is 8% voltage drop from start of charge. I get about 3.5% drop just on the meter side at home.

That's about what I noticed when it would current limit. On a good power supply it will work to 40amps without current reducing. The wire is a soow 12awg 6 pole. Each pole is running 2 12 awg wires in parallel so the wire is very flexible. Its gauge equivalent to a 9 awg with a little better heat dissipation.

The neutral prong is removed on the male end for both 30 and 50 amp outlets.

With 70 feet and Washer or Range outlet capability, turns every house built after 1996 into a potential L2 charging station....

It fits perfectly in the frunk pocket.

 

[RossRAllen]

Thanks for this useful information. Just what I was looking for!

 

[Cyclone]

The problem with the Camco cords (I have one), is they are VERY heavy and stiff.

I think the evseadapters.com version has 1 less wire and is lighter and more flexible.

Assuming you only need it for EV charging, I'd go with the evseadapters.com cord, just ask for him to make it 30ft.

I tried. They wouldn't respond to me about making it at 30 ft, so I bought the Camco.

- - - Updated - - -

Spoke with EVSE Adapters. I like the fact that their 14-50 extension cord is lighter than the Camco, and offers the utility to plug in different plugs without having to mess with additional adapters. They are willing to make a 30' one. I'm waiting to get a price from them.

You are getting further than I. After three emails and two phone calls, I had to give up. They seem totally unwilling to talk with me about ordering a 30 ft. I had to end up buying the cheaper Camco product.

 

[Rocky_H]

You are getting further than I. After three emails and two phone calls, I had to give up. They seem totally unwilling to talk with me about ordering a 30 ft. I had to end up buying the cheaper Camco product.

Aww, shoot. I would have sold you mine. After building one adapter cable from buying the wire and plug and outlet heads, I found that it wasn’t very hard. I would have gladly sold my 30 foot Camco to build a 40 or 50 foot one that’s thinner, lighter, and more flexible.

 

[AWDtsla]

I've done some experiments with 8/3 cable and 40 Amps. There is a noticeable, but acceptable temperature rise when the cable is laid out in an open pattern on the garage floor. The problem comes if you leave the cable coiled up. In that configuration, the runs of cable lay next to each other, and heat each other up. I did not do any calibrated measurements, but I considered the temperature rise unacceptable and dangerous with several loops in a coil.

If you do use 8/3 to carry 40 Amps, I strongly recommend that you use care and unroll coils completely. Also, check the cable and connections for unacceptable temperature rise, after connection, at 5, 15, and 30 minutes.

So I wanted to double check how bad 8 AWG actually is. Although I wouldn't try and run it coiled up, the wire in the UMC is dual 11 AWG, which is actually equivalent to a single 8 AWG. The UMC cable gets slightly warm to the touch while running at 40A. Also the voltage drop is only 0.53% over 25 feet, which is negligible. If really worried, the 105C rated SEOOW would probably let it run safely even when coiled. 105C is really damn hot, threshold of pain is ~54C.

 

[Firewired]

This goes back to my initial post. The customer service at EVSE Adapters is the absolute pits. I spoke to a person there who stated they would be able to order the Universal plug in 30' length. I wasn't sure if the 30' length would be needed until I started getting feedback from this thread. I told him I would call him back if I indeed wanted to put my order in. The person said, calling was the best way to get hold of them. I have left three messages over multiple days and sent two unanswered emails. I guess there is my answer there. I would be afraid to order from them at this point, and have an issue with the cord there would be no way to to get hold of anyone. It's a really bad sign when you can't even get hold of a person to put your order in, let alone possibly needing to after the purchase.

 

[Cottonwood]

So I wanted to double check how bad 8 AWG actually is. Although I wouldn't try and run it coiled up, the wire in the UMC is dual 11 AWG, which is actually equivalent to a single 8 AWG. The UMC cable gets slightly warm to the touch while running at 40A. Also the voltage drop is only 0.53% over 25 feet, which is negligible. If really worried, the 105C rated SEOOW would probably let it run safely even when coiled. 105C is really damn hot, threshold of pain is ~54C.

That is exactly why I recommend that folks not coil the excess UMC cable in several tight coils, but instead loop them into a few loose coils.

Let's use your numbers: 0.53%*240 Volts is 1.3 Volts; 1.3V*40A is about 50 Watts. Make a longer #8 extension cord and that can easily be 100 to 200 Watts. Put 200 Watts in a tightly coiled cable and temps will rise; leave it stretched out and the temps are not too bad...

From American wire gauge - Wikipedia, the free encyclopedia: #8 copper is 0.6282 milliOhm per foot. We have to double that for out and back in the extension cord, so 40A[SUP]2[/SUP]*0.0006282Ohm/ft*2ft is about 2 Watts per foot of extension cord. Once again, not a big deal for stretched out cord, but coil many turns on top of each other and things start getting VERY warm.

Just be careful!

 

[TonyWilliams]

Aww, shoot. I would have sold you mine. After building one adapter cable from buying the wire and plug and outlet heads, I found that it wasn’t very hard. I would have gladly sold my 30 foot Camco to build a 40 or 50 foot one that’s thinner, lighter, and more flexible.

In searching for extension cables, I found a J1772 extension cable that is sold as "light and super flexible". The same company also sells that same cable by the foot.

Wouldn't it be possible to use that for a regular extension cord?

 

[Gremlin]

I have a 50 foot 240v / 30 AMP extension cord, and also a 100 foot 15 amp extension cord I got from Lowe's. The later is on a reel that I have used while in the middle of nowhere VA (Tappahannock, VA) to get 6 miles an hour with NEMA 6-15. I have like 4 adapters in my car, and a CHAdeMO ​adapter.