How many amps can the Model S pull from a NEMA 14-50?

[William13]

I have wired for my HPWC but it will not be available when the car is delivered. The electricians placed a NEMA 14-50 plug for now. Ordinarily this plug would be limited to 40 amps continuous. Will the Model S pull only 40 amps or will it pull 50? How dangerous would it be? It is on a 100 amp breaker.

Later it will be replaced by the HPWC.

 

[dhrivnak]

By code and by any licensed electrician, you are limited to 40 amps of charging. Legally an electrician can not put a 100 amp breaker on a plug rated 50 amps. That said I have a 70 amp breaker on my NEMA 14-50 and I have successfully pulled 64 amps for hours with no ill effects, my set us is not designed to be pugged into on a normal basis. But that said I know if "inspected" I would have to replace the 70 amp breaker with a 50 to be fully code compliant.

I also suspect the Tesla cord to plug into a NEMA 14-50 will be limited to 40 amps just like the Roadster.

 

[doug]

Probably the most the UMC will allow you to pull is 40A set via the pilot signal.

 

[doug]

Legally an electrician can not put a 100 amp breaker on a plug rated 50 amps.

Aren't you allowed to have two outlets on the same breaker?

 

[Andrew Wolfe]

Yes, in some cases - but the breaker cannot exceed the capacity of a single plug.

 

[ChadS]

Mine's plugged in to a 14-50 now; I just verified that I can't ask it to pull more than 40A.

 

[goyogi]

How does it know how many amps it can pull?

 

[Lloyd]

Mine's plugged in to a 14-50 now; I just verified that I can't ask it to pull more than 40A.

That is why the breaker needs to be paired correctly. A fire can result!

 

[dadaleus]

How does it know how many amps it can pull?

I think the Tesla connector tells the car the maximum. On the Roadster (others here will have a better technical explanation), changing the tip on the UMC actually changed the maximum the car will draw accordingly. The Model S one does the same thing with the 120 volt vs. 240 volt tips. I assume this would be true for other tips as well, but I haven't seen them yet.

 

[vfx]

How many ping pong balls fit in the frunk?

 

[bonnie]

How many ping pong balls fit in the frunk?

What color is the sky over there?

 

[ModelS1079]

That is why the breaker needs to be paired correctly. A fire can result!

Pulling more than 40A from a NEMA 14-50 sounds like a bad idea. So, teach me, my friends more geeked than I: I understand a NEMa 14-50 can carry 50A, but that's an over-build so it'll safely carry 40A. So that explains NEMA 14-50. But what do NEMA and 14 mean?

- - - Updated - - -

Okay, even a junior-varsity geek can google:

http://en.wikipedia.org/wiki/NEMA_connector

 

[gg_got_a_tesla]

How many ping pong balls fit in the frunk?

The next Google tech interview question, I'm sure. They had a version of it for a school bus

Apologize on Eric's behalf for going off-topic...

 

[Timothy]

Pulling more than 40A from a NEMA 14-50 sounds like a bad idea. So, teach me, my friends more geeked than I: I understand a NEMa 14-50 can carry 50A, but that's an over-build so it'll safely carry 40A. So that explains NEMA 14-50. But what do NEMA and 14 mean?

- - - Updated - - -

Okay, even a junior-varsity geek can google:

NEMA connector - Wikipedia, the free encyclopedia

And for a elementary school geek who can google, I learn our cars are actually electric ranges! :wink:

 

[FlasherZ]

Aren't you allowed to have two outlets on the same breaker?

NEC 210.21(B)(1): "A single receptacle installed on an individual branch circuit shall have an ampere rating not less than that of the branch circuit."
NEC 210.21(B)(3): "Where connected to a branch circuit supplying two or more receptacles or outlets, receptacle ratings shall conform to the values listed in Table 210.21(B)(3), or, where rated higher than 50 amperes, the receptacle rating shall not be less than the branch-circuit rating."

The only place where a smaller receptacle rating is allowed versus the branch circuit rating is where 15A receptacles are used on 20A circuits (120V). So, 50A breaker maximum on any circuit that has a NEMA 14-50R attached.

 

[TEG]

I think the Tesla connector tells the car the maximum. On the Roadster (others here will have a better technical explanation), changing the tip on the UMC actually changed the maximum the car will draw accordingly. The Model S one does the same thing with the 120 volt vs. 240 volt tips. I assume this would be true for other tips as well, but I haven't seen them yet.

Yes, that is correct. When you change plug ends it has a mechanism to tell the UMC to adjust the ampacity signal accordingly.
So the UMC then tells the car not to draw more current than is considered safe for the plug type in use.

 

[jkirkebo]

Yes, that is correct. When you change plug ends it has a mechanism to tell the UMC to adjust the ampacity signal accordingly.
So the UMC then tells the car not to draw more current than is considered safe for the plug type in use.

Correct me if I'm wrong, but I don't think the UMC supports more than 40A anyway ? So 40A would also be max on a 14-60 plug ?

 

[TEG]

Correct me if I'm wrong, but I don't think the UMC supports more than 40A anyway ? So 40A would also be max on a 14-60 plug ?

For Roadster, yeah, I think 40A was max...
http://www.teslamotors.com/roadster/charging/universal-mobile-connector
So, it puts out 40A signal for NEMA 14-50, NEMA6-50,and lower signals when it detects other plug ends.

So far, it looks like Model S UMC is also 40A max:
http://www.teslamotors.com/models/charging/#/outlet
I don't see any mention of NEMA 14-60 plug support there at all.

 

[dmetcalf]

My 14-50 draws a max of 40A and takes 245 V for 31 mi/ hr of recharge. 28 mi/hr of recharge if I am sitting with air on and listening to music...

 

[ModelS1079]

And for a elementary school geek who can google, I learn our cars are actually electric ranges! :wink:

Yes, and I believe there is a self-cleaning option for the Model S as well, like the Electric Range.