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Has anyone tried this 14-50 extension cord?

Yanquetino

Member
Dec 2, 2007
127
158
Ivins, Utah (St. George area)
I don't have this extension, but predict that it will plug in to 14-30, 14-50, and 14-60 outlets. The "trick" is that it is missing the lower pin that is different on those three types of plugs (see below). I had an adapter with my previous Nissan LEAF just like this (also see below), and can attest that it worked with both 14-30 and 14-50 outlets without any problem. I never had a chance to plug into a 14-60 outlet, but I'm confident it would also work.

Screen Shot 2020-07-09 at 12.04.06 PM.png
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wws

Member
Aug 11, 2014
981
1,013
Northern California
The only physical difference between 14-30, 14-50, and 14-60 is the shape of the neutral blade. The neutral is used when 120V is needed - for example, the clock/timer or light bulbs in a kitchen range. However EV charging doesn't use the neutral. So by eliding the neutral blade, the extension cord can use three conductors instead of four - with corresponding weight, size, and cost savings. But realize that it can ONLY be used for EV charging or other 240V-only applications. If you try to use it with your RV, kitchen range, or clothes dryer, which need both 120V and 240V, you'll likely be very sorry...

I've mentioned on other threads that Tesla really should deliver the 14-30 adapter without the neutral blade. That would allow it to also plug into a 14-50 (or the very rare 14-60). Obviously it would be safe because amperage would be set to 24 amps regardless of which receptacle it was plugged into.
 

wws

Member
Aug 11, 2014
981
1,013
Northern California
Actually, 24A is the limit from a 14-30 outlet. When plugged into 14-50 and 14-60 receptacles, the Tesla Mobile Connector pulls its maximum 32A. At least that's what I've experienced with 14-50 in RV panels at campgrounds.

My comment on “Tesla should remove the neutral blade...” was only in reference to the 14-30 adapter. I would NOT suggest such a change to the 14-50 adapter.
 

Yanquetino

Member
Dec 2, 2007
127
158
Ivins, Utah (St. George area)
My comment on “Tesla should remove the neutral blade...” was only in reference to the 14-30 adapter. I would NOT suggest such a change to the 14-50 adapter.
Hmmm. I must be missing something, because I don't see the problem. That's what I did with the 14-50 adapter I had with my previous LEAF, and could then use it with all three receptacles: 14-30, 14-50, and 14-60. With my Model 3, however, I just purchased a separate 14-30 adapter to use with the Tesla Mobile Charger's 14-50 plug.
 

eladts

Member
Jul 31, 2016
782
1,068
Brookline, MA
Hmmm. I must be missing something, because I don't see the problem. That's what I did with the 14-50 adapter I had with my previous LEAF, and could then use it with all three receptacles: 14-30, 14-50, and 14-60. With my Model 3, however, I just purchased a separate 14-30 adapter to use with the Tesla Mobile Charger's 14-50 plug.

If you remove the neutral blade from a 14-50 adapter and plug it to a 14-30 socket, the car will try to pull 32A and will overload the socket, which is rated for continuous 24A. However, if you pull the neutral blade from a 14-30 adapter and plug it to a 14-50 socket there is no issue.
 

Yanquetino

Member
Dec 2, 2007
127
158
Ivins, Utah (St. George area)
If you remove the neutral blade from a 14-50 adapter and plug it to a 14-30 socket, the car will try to pull 32A and will overload the socket, which is rated for continuous 24A. However, if you pull the neutral blade from a 14-30 adapter and plug it to a 14-50 socket there is no issue.
I never had that problem with my LEAF's onboard charger, as it would only pull its maximum 16 amps from either receptacle. Maybe (?) the Tesla Mobile Charger might also sense and adapt to the amperage from the outlet, but… if not, I think it's possible to set a 24A limit from within the car before plugging a modified 14-50 plug into a 14-30 outlet. In fact, my 14-30 adapter has a label on it with the instruction to do that before using it.
 
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wws

Member
Aug 11, 2014
981
1,013
Northern California
I never had that problem with my LEAF's onboard charger, as it would only pull its maximum 16 amps from either receptacle. Maybe (?) the Tesla Mobile Charger might also sense and adapt to the amperage from the outlet, but… if not, I think it's possible to set a 24A limit from within the car before plugging a modified 14-50 plug into a 14-30 outlet. In fact, my 14-30 adapter has a label on it with the instruction to do that before using it.

The adapters have a little built-in resistor that tells the UMC what the maximum current level is for the particular plug attached to it. So a 14-30 adapter tells the UMC to tell the car it can support 24 amps max. Likewise, a 14-50 adapter tells it to set a 32 amp max. A 5-15 will set the max to 12 amps, etc.
 

Yanquetino

Member
Dec 2, 2007
127
158
Ivins, Utah (St. George area)
The adapters have a little built-in resistor that tells the UMC what the maximum current level is for the particular plug attached to it. So a 14-30 adapter tells the UMC to tell the car it can support 24 amps max. Likewise, a 14-50 adapter tells it to set a 32 amp max. A 5-15 will set the max to 12 amps, etc
So… it's not necessary to set the charging amperage via the touchscreen, because the adapter tells the charger how many it can handle? I wonder if that's also the case with my non-Tesla adapters? Hmmm. Maybe I should try to connect my UMC with its 14-50 adapter to my extension cord with my 14-30 adapter on the other end, plugged into my dryer outlet, just to see what the touchscreen displays…?
 

RayK

Active Member
Apr 5, 2016
1,963
1,911
San Jose, CA
My understanding is that only the Tesla mobile connector AC plugs (e.g., like a NEMA 14-50 adapter) have the correct resistors built into them so that the mobile connector knows what you're using. If you violate the implied amperage connection to AC power by using other plug adapters or extension cords that converts a lower amperage wall outlet to something higher (i.e., using a 14-30P to 14-50R cord, so that you can connect the UMC's 14-50 plug into it), the car will still assume that the maximum amperage draw is what the mobile connector is using. The car will try to draw 32A (max for the mobile connector) out of a circuit that is only rated for 24A (14-30 outlet).

You can always use a Tesla mobile connector plug that's rated at a LOWER amperage to plug into the wall with a HIGHER amperage through the use of plug adapters/extension cords and have the car automatically (and safely) set the charge rate. If you go the other way, (higher A Telsa plug on a lower A outlet) then you have to manually limit the charge rate on the screen in order to prevent the breaker from tripping.

edit: The reason that this is fresh in my mind is that I'm finally looking into installing my Gen2 HPWC in my garage. I'm planning to put in a 60A breaker, the HPWC, a 14-60 outlet and a transfer switch to select between the two. I would need a 14-60P to 14-50R adapter if/when using the mobile connector but I'd be able to get the maximum charge rate possible with either hardware.
 
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ZOMGVTEK

Member
May 19, 2015
559
434
'Merica
Ray has it. The only way the car knows the current it can pull is from what connector is shoved into the mobile connector. If you use a 14-50, the car is going to assume it’s plugged into a 50A outlet and will allow the full 32A. It has absolutely no way to know otherwise. There’s nothing anyone can do to ‘sense’ the safe current a circuit can provide since there’s a huge number of factors the car is entirely unaware of. It also looses temp sensing, since it would be only sensing at the mobile connector end, so the extension cord can be burning and it won’t know unless the end the 14-50 is plugged into gets hot. You can adapt a 14-50 to a regular 15A 120V outlet and the car will assume it can charge at 32A. And as a side note, a 30A breaker may never trip operating at 32A. It depends mostly on the specific breaker, ambient temperature, loads on adjacent breakers. That small of an overload will typically take a very long time to trip, so don’t assume the breaker will pop if you draw too much, you need to go quite a bit over for it to trip quickly.
 
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wws

Member
Aug 11, 2014
981
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Northern California
So… it's not necessary to set the charging amperage via the touchscreen, because the adapter tells the charger how many it can handle?

Correct. Though you might have to dial down the current a bit if you plug into a 'sketchy' electrical circuit - such as a 5-15 that has other stuff on the same circuit.

I wonder if that's also the case with my non-Tesla adapters? Hmmm. Maybe I should try to connect my UMC with its 14-50 adapter to my extension cord with my 14-30 adapter on the other end, plugged into my dryer outlet, just to see what the touchscreen displays…?

It will display 32 amps because you are using the 14-50 adapter.

For receptacle types that are not supported by Tesla, I like to point folks to evseadapters. Their UMC adapters correctly set the max current just like the Tesla adapters do. (I have no affiliation with them - just a happy customer. I have one of their TT-30 adapters.)

For Tesla Model S, Model 3, Model X, & Model Y Gen 2 – EVSE Adapters
 

RayK

Active Member
Apr 5, 2016
1,963
1,911
San Jose, CA
For receptacle types that are not supported by Tesla, I like to point folks to evseadapters. Their UMC adapters correctly set the max current just like the Tesla adapters do. (I have no affiliation with them - just a happy customer. I have one of their TT-30 adapters.)

For Tesla Model S, Model 3, Model X, & Model Y Gen 2 – EVSE Adapters
I had just ordered one of their TT-30 adapters last week but then cancelled it a couple of days later (was backordered at the time) because I realized I could use a TT-30P to 14-30R adapter with my mobile connector. $75 vs. $30 on Amazon. Yes it doesn't have the temperature sensor right at the plug in the wall but a short 1' extension cord using 10AWG wire shouldn't be a problem.

Note that I already had the 14-30 adapter for my UMC (@ $35) so I'm really only saving $10 if I didn't have one.
 
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Yanquetino

Member
Dec 2, 2007
127
158
Ivins, Utah (St. George area)
The car will try to draw 32A (max for the mobile connector) out of a circuit that is only rated for 24A (14-30 outlet).
TRUE! Just for fun, I tried an experiment:

Model 3 <— MCU <— Tesla 14-50 adapter <— 14-50 extension <— ACWorks 14-30 adapter <— 14-30 dryer outlet

Sure enough, the car started charging and soon peaked at the MCU's maximum of… 32A. Yeow! I immediately stopped the charge.

It is therefore essential to set the maximum rate on the touchscreen to 24A when using my 14-30 adapter with the MCU.

I think I will contact ACWorks and suggest that they also start to include a small resistor in their adapters to limit the amps according to the plug's matching receptacle —like EVSE Adapters.

Or maybe… I'll just buy an equivalent Tesla adapter, since it already has a resistor, and forget about ever using my extension cord. Unlike was the case with my LEAF, I've found that I have yet to need it: Superchargers are readily available nationwide and RV campgrounds have their panels right next to the camping space.
 

RayK

Active Member
Apr 5, 2016
1,963
1,911
San Jose, CA
Or maybe… I'll just buy an equivalent Tesla adapter, since it already has a resistor, and forget about ever using my extension cord. Unlike was the case with my LEAF, I've found that I have yet to need it: Superchargers are readily available nationwide and RV campgrounds have their panels right next to the camping space.
I`ll have four UMC plugs, the arriving-today TT-30P to 14-30R adapter, a CHAdeMO adapter, along with two J-1772 adapters in my car. While I'm probably not going to be spending much time at RV parks, I got the TT-30 adapter just in case. My daughter has an RV and just completed a one year trip around the US. She spent several months in Maine and Florida but is now "home" in Oregon so it could come in handy when I visit. The CHAdeMO adapter has been used about a dozen times at ChargePoint stations locally and I used to use the J-1772 weekly at work.

I believe somebody here said that EVSEadapters buys OEM Tesla UMC plugs and converts them with "new" plugs. It may explain why they cost so much ($35, plus parts and labor).
 
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wws

Member
Aug 11, 2014
981
1,013
Northern California
...
I think I will contact ACWorks and suggest that they also start to include a small resistor in their adapters to limit the amps according to the plug's matching receptacle —like EVSE Adapters.

Nothing ACWorks can do about their adapter. The resistor in a UMC adapter is purely for signalling purposes.

Or maybe… I'll just buy an equivalent Tesla adapter, since it already has a resistor, and forget about ever using my extension cord. Unlike was the case with my LEAF, I've found that I have yet to need it: Superchargers are readily available nationwide and RV campgrounds have their panels right next to the camping space.

What you can do is buy the Tesla 14-30 adapter and grind off the neutral blade. Basically what I mentioned Tesla should do way back in post #6.
 

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