Tesla engineer warns against using extension cords at Superchargers

[potato]

400 amps is a common sized feed for a house. U.L. certifies those components no problem. And lots of commercial and industrial systems way larger than that.

With permanent connections torqued to a specification, yes. But not with connectors that the end user can plug and unplug at will. We have hundreds-of-amps capable connectors for 12 volts, for example winches, but 400+ volts is a whole other ball game.

I kind of agree this whole idea probably can't be made fully safe in the long run. Maybe for the first 100 insertions but if anything starts to wear, the slightest bit of arcing... it's game over.

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[BeeKind]

400 amps is a common sized feed for a house. U.L. certifies those components no problem. And lots of commercial and industrial systems way larger than that.

Also, the connection from the connector on the fender of the car to the battery in the car is just some wire. Same exact problem as the extension.

By far the weakest point is the connection. Tesla's standard has very small pins for the amount of current. That is where all the heat is going to be. Certainly possible conduct the heat away from the pins with a thick enough piece of copper on either side. And nothing except cost and awkward bulkiness stops the extension from being liquid cooled, either. Could have a small fan and radiator box...

It all just boils down to cost. As I mentioned, its difficult to make it cheap enough for everybody to carry one around.

The best solution would be for Tesla to have made their cables 6 feet longer to start with.

You see how the thing feeding your house is sheathed from the second it touched your house and is hardwired? I'm not saying you can't carry that amount of current on cables. I'm saying they don't make consumer extension cables for this purpose and never will.

 

[RickKeen]

You see how the thing feeding your house is sheathed from the second it touched your house and is hardwired? I'm not saying you can't carry that amount of current on cables. I'm saying they don't make consumer extension cables for this purpose and never will.

Wires to my house are just cables buried in the dirt. And have seen plenty of flexible cables carrying high power loads in industrial settings.
Its not magic. Its just expensive.
So I partially disagree on the "never will" part - they will make them, but they will be expensive. Not very many people will buy them.

 

[BeeKind]

Wires to my house are just cables buried in the dirt. And have seen plenty of flexible cables carrying high power loads in industrial settings.
Its not magic. Its just expensive.
So I partially disagree on the "never will" part - they will make them, but they will be expensive. Not very many people will buy them.

No, you're wrong, this stuff is regulated, we have code. You're not allowed to just engineer and do what you want. There are many reasons within the EVSE section of the NEC why this doesn't work which stipulates the requirements for AC and DC cables.

You should spend some time in ChatGPT, she's very well versed in the code and will have 0 problems informing you while this is literally not a possible thing to make happen on any practical level.

You understand someone has to certify it right, even if it could somehow conform to code? No one is going to certify it.

Just cause you can plug shit in 3 phase in an industrial setting doesn't mean this is possible.

 

[BSull]

So in March Tesla the company stated they were working on an extension cable for nacs charging and now because one person from Tesla says extension cable is bad we are all running around with our hair on fire?

 

[Monkey]

So in March Tesla the company stated they were working on an extension cable for nacs charging and now because one person from Tesla says extension cable is bad we are all running around with our hair on fire?

No, hair on fire is what happens when you use the extension cable.

Tesla never officially announced any such product. One of Tesla’s non-engineers said that they might be able to look into it. And I think Elon re-tweeted it and then it disappeared.

 

[Firn]

I just have to say way, lots of negative nancies here.

The concerns are legitimate but they also fail to recognize that for every concern listed the solution is ALREADY in use AT each cabinet.

Connections to handle this load are absolutely possible. They are quite literally the exact same connections we already use, there is just another one. Yes, that does increase the failure RATE, but having a second does not mean it won't work exactly the same as the first.

Extensions are possible. There is a cable from the charging port to the battery, that is an extension cable. Is the wiring in the truck liquid cooled? That I don't know but I have vener seen mention of it.

I have seen some good points but also ones that have solutions that are literally on our vehicles right now

 

[BeeKind]

I just have to say way, lots of negative nancies here.

The concerns are legitimate but they also fail to recognize that for every concern listed the solution is ALREADY in use AT each cabinet.

Connections to handle this load are absolutely possible. They are quite literally the exact same connections we already use, there is just another one. Yes, that does increase the failure RATE, but having a second does not mean it won't work exactly the same as the first.

Extensions are possible. There is a cable from the charging port to the battery, that is an extension cable. Is the wiring in the truck liquid cooled? That I don't know but I have vener seen mention of it.

I have seen some good points but also ones that have solutions that are literally on our vehicles right now

You're talking about a cable that would likely cost over $2000 retail if someone went through the trouble of developing one if national code would even allow it. The kinds of connections you're talking about are "dumb" 3-phase industrial connections that don't exist in residential applications. The challenges to conform to NACS - NACS would be tremendous.

The safety problems alone I'm not sure could be overcome. What if the cable becomes exposed, who is liable for it safely disconnecting? The station? The car? The cable manufacturer? You?

This theoretical cable is well beyond what the government lets people handle in this manner. For good reason. Failures will occur and they will be damaging.

 

[BeeKind]

Guys, this is arc flash territory. As in, people will be causing this to happen. Perhaps not en masse, but introducing failure at these currents results in deadliness. There's a reason why I'm being so incredulous over this not being a practical possibility

 

[Firn]

You're talking about a cable that would likely cost over $2000 retail if someone went through the trouble of developing one if national code would even allow it. The kinds of connections you're talking about are "dumb" 3-phase industrial connections that don't exist in residential applications. The challenges to conform to NACS - NACS would be tremendous.

The safety problems alone I'm not sure could be overcome. What if the cable becomes exposed, who is liable for it safely disconnecting? The station? The car? The cable manufacturer? You?

This theoretical cable is well beyond what the government lets people handle in this manner. For good reason. Failures will occur and they will be damaging.

Cost is what it is. You are right, but it's not really pertinent to if it can be done.

Any and all connections are the exact connections in use today on these exact vehicles to do these exact thing. The NACS handle is a connection, the port on the car is a connection. They already do thus job and adding one more won't change that.

The charging specifican already deals with disconnect. That is no different than the cables on the station itself.
Who is liable is a WHOLE different argument that gets into negligence of the cable owner, the manufacture of the cable, and all that is impacted by any certifications (if they exist)

This theoretical cable is LITERALLY the cable in use already. It is absolutely no different than what is used today other than it is longer and there is an extra set of NACS/CCS connectors in the middle. It may not be an exact match to whatever it is connected to, but it is just cable and all evs already use a bunch of it

 

[BeeKind]

Cost is what it is. You are right, but it's not really pertinent to if it can be done.

Any and all connections are the exact connections in use today on these exact vehicles to do these exact thing. The NACS handle is a connection, the port on the car is a connection. They already do thus job and adding one more won't change that.

The charging specifican already deals with disconnect. That is no different than the cables on the station itself.
Who is liable is a WHOLE different argument that gets into negligence of the cable owner, the manufacture of the cable, and all that is impacted by any certifications (if they exist)

This theoretical cable is LITERALLY the cable in use already. It is absolutely no different than what is used today other than it is longer and there is an extra set of NACS/CCS connectors in the middle. It may not be an exact match to whatever it is connected to, but it is just cable and all evs already use a bunch of it

Being cost prohibitive most people would think would be the #1 reason why it can't be done.

You're not understanding the disconnect issue but it's just one issue among many. Right now Tesla is in charge of detecting if there's a break in the shielding and exposure to the outside world and will shut down the console immediately. How does Tesla know what is going on with your extension cord? What if whatever measures doesn't communicate with Tesla (or EVGo, or Electrify America) - then those safety features are either disabled or the cable doesn't work.

It's not "LITERALLY the cable in use already" - you're showing a fundamental lack of understanding of the cables.

Electricity isn't a thing you should Dunning Krugger (though low chance of anyone actually trying this)

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