208v panel to nema 14-50 not charging my Model 3 in Arizona

[BMMYP]

My electrician has hooked up a nema 14-50 outlet 3 feet from my panel at work; which is a 208v system in the USA. When I plug in the $520 Tesla corded mobile connector (14-50 head), the light on cord turn red, and the car does not charge. My electrician has checked the voltage at the 14-50 outlet, and it's power numbers are correct. The same $520 cord, when I bring it home, charges my car on my nema 14-50 outlet from my home 220v system.

Any idea why my car will not charge at work from there 208V that is common in businesses in the USA?
It the NEMA 14-50 not wired right at work? Or not grounded right?

Thanks in advance. -B

 

[davewill]

It's probably a bad ground, but as part of troubleshooting, you might want to try your mobile connector at work, assuming you have the 14-50 adapter.

 

[Tam]

My electrician has hooked up a nema 14-50 outlet 3 feet from my panel at work; which is a 208v system in the USA. When I plug in the $520 Tesla corded mobile connector (14-50 head), the light on cord turn red, and the car does not charge. My electrician has checked the voltage at the 14-50 outlet, and it's power numbers are correct. The same $520 cord, when I bring it home, charges my car on my nema 14-50 outlet from my home 220v system.

Any idea why my car will not charge at work from there 208V that is common in businesses in the USA?
It the NEMA 14-50 not wired right at work? Or not grounded right?

Thanks in advance. -B

I have no idea but maybe it has to be phase differences between residential 240V and industrial 208V. Single phase vs. 3 phase?

Your appliance wouldn't get the desired voltage if you got the wrong phase (although the electrician meter does because it's designed for both single and 3 phase)?

 

[BMMYP]

My electrician has hooked up a nema 14-50 outlet 3 feet from my panel at work; which is a 208v system in the USA. When I plug in the $520 Tesla corded mobile connector (14-50 head), the light on cord turn red, and the car does not charge. My electrician has checked the voltage at the 14-50 outlet, and it's power numbers are correct. The same $520 cord, when I bring it home, charges my car on my nema 14-50 outlet from my home 220v system.

Any idea why my car will not charge at work from there 208V that is common in businesses in the USA?
It the NEMA 14-50 not wired right at work? Or not grounded right?

Thanks in advance. -B

My electrician says we have the nema 14-50 set up as a :single phase with a neutral"....

 

[iluvmacs]

How many flashes from the red light? That will give you a clue... https://www.tesla.com/sites/default...bile_connector_owners_manual_40_amp_en_US.pdf
Page 11

 

[BMMYP]

I have no idea but maybe it has to be phase differences between residential 240V and industrial 208V. Single phase vs. 3 phase?

Your appliance wouldn't get the desired voltage if you got the wrong phase (although the electrician meter does because it's designed for both single and 3 phase)?

Thanks for the info.... he does say it's single phase with a neutral.... maybe that's not going to work...

 

[BMMYP]

How many flashes from the red light? That will give you a clue... https://www.tesla.com/sites/default...bile_connector_owners_manual_40_amp_en_US.pdf
Page 11

Thank you... I believe it was a solid red light.... the manual only states flash of red lights..... I will check it again Monday.... I appreciate the help

 

[Big Earl]

 

[AlanSubie4Life]

View attachment 451536

Which version of the UMC are we talking about here? I see the Gen 1 manual and stuff referenced above.

Anyway, here is Gen 2 lights info (page 11); there are a lot more different combos:

https://www.tesla.com/sites/default...bile_connector_owners_manual_32_amp_en_US.pdf

Don't fully understand what the problem might be. The UMC is rated for 100-240V AC single-phase.

I didn't think the UMC used the neutral (works fine with a 6-50)...so it would not like to see one of the (normal) hots (line 1/2) in a 14-50 plug be left open, if that's the way it is done (pretty sure that would be wrong anyway - but I am not an electrician, and have never worked with commercial 208V phase-to-phase stuff or whatever). I'm curious to see how the outlet is wired, exactly.

I really have no idea what I'm talking about here, but I bet if we saw how the outlet/receptacle was wired it would be pretty clear.

Should be 208V L1 to L2 and each should be 120V to the neutral. I think. I am not an electrician. 208V = sqrt(3)*120V

 

[Tam]

Thanks for the info.... he does say it's single phase with a neutral.... maybe that's not going to work...

Like I said, I have no ideas but the above setting is desireable because that's residential settings: Single phase with a neutral.

If so, it should be 240V.

How did he get 208V? That's for commercial 3 phase voltage, 208V is not residential single phase!

 

[Big Earl]

Like I said, I have no ideas but the above setting is desireable because that's residential settings: Single phase with a neutral.

If so, it should be 240V.

How did he get 208V? That's for commercial 3 phase voltage, 208V is not residential single phase!

208 volts is commercial power, while 240 volts is residential power (typically). How each is derived is described in many places online. Model 3 can charge just fine from both.

240 is two legs of a split phase or single phase power system, while 208 is two legs (or three) of a three phase power system.

 

[Big Earl]

Which version of the UMC are we talking about here? I see the Gen 1 manual and stuff referenced above.

Anyway, here is Gen 2 lights info (page 11); there are a lot more different combos:

https://www.tesla.com/sites/default...bile_connector_owners_manual_32_amp_en_US.pdf

Don't fully understand what the problem might be. The UMC is rated for 100-240V AC single-phase.

I didn't think the UMC used the neutral...so it would not like to see one of the (normal) hots (line 1/2) in a 14-50 plug be left open, if that's the way it is done. I'm curious to see how the outlet is wired, exactly.

But I really have no idea what I'm talking about here, but I bet if we saw how the outlet/receptacle was wired it would be pretty clear.

Good catch. I posted the troubleshooting page from the link earlier in the thread, which seems to be Gen 1. Gen 2 has many more status light combinations.

 

[justsomeguy]

Like I said, I have no ideas but the above setting is desireable because that's residential settings: Single phase with a neutral.

If so, it should be 240V.

How did he get 208V? That's for commercial 3 phase voltage, 208V is not residential single phase!

He did say his panel at work. Maybe he's part of a big commercial building that has 3 phase power giving him 208v in some way?

 

[Feathermerchan]

208V 3 phase is 120V to neutral on each of the three phases and 208V Phase to phase.
This is very common in buildings.

Residential single phase is 120V to neutral and 240V Phase to phase.

A Nema 14-50 has 4 wires. Two phase wires, a neutral and a ground. All 4 must be connected properly.

Tell us the flash code for the red light and we can be of more help.

 

[AlanSubie4Life]

Thank you... I believe it was a solid red light.... the manual only states flash of red lights.....

The Gen 2 manual says this is a self-check fail - but since it works at home the UMC is still good.

With a solid red light, since it's not complaining about a grounding problem, I suspect that one of the L1/L2 pins is not connected...not sure how it would power up without the presence of a ground return (not sure it even uses the neutral with the 14-50 adapter?) - it's not supposed to use the ground pin for that return path of course...but it may be that without a proper return path it just can't go through all its self checks - but since it is still grounded and has a single hot connection, it at least can power up enough to tell you it is no good.

 

[233.3]

Commercial 208 3-phase typically comes from a 208/120 wye transformer. As with any three phase power there are three legs (hot wires). The voltage between any two of the legs on a 208/120 (L1-L2, L1-L3 OR L2-L3) will be 208v. Each leg will be 120v to ground or neutral.

208v can also come from a 240v three-phase delta transformer. The voltage between any two legs will be 240v. The voltage between two of the legs and the neutral (i.e. L2-N and L3-N) will be 120v. The other leg will be 208v to the neutral. That leg is often referred to as the high leg. If your electrician gave you just the 208v high leg and the neutral and that is what he is referring to as 208 single phase then that is probably the cause.

Correctly wired, the 14-50 should have two hot legs, one ground, and one neutral. Both hot legs are intended to be 120v to neutral.

If one of the two hot legs is the high leg that may be the problem but since I do not think the UMC uses the Neutral I do not think that would matter.

To check this, if you use a volt meter to measure the voltage between each of the outer two rectangular holes and the center one, one at a time, the voltage should be 120. If one is 208 and the other is zero that is your problem. If one is 208 and the other is 120 that could be the problem but I do not think that should matter.

 

[Big Earl]

Commercial 208 3-phase typically comes from a 208/120 wye transformer. As with any three phase power there are three legs (hot wires). The voltage between any two of the legs on a 208/120 (L1-L2, L1-L3 OR L2-L3) will be 208v. Each leg will be 120v to ground or neutral.

208v can also come from a 240v three-phase delta transformer. The voltage between any two legs will be 240v. The voltage between two of the legs and the neutral (i.e. L2-N and L3-N) will be 120v. The other leg will be 208v to the neutral. That leg is often referred to as the high leg. If your electrician gave you just the 208v high leg and the neutral and that is what he is referring to as 208 single phase then that is probably the cause.

Correctly wired, the 14-50 should have two hot legs, one ground, and one neutral. Both hot legs are intended to be 120v to neutral.

If one of the two hot legs is the high leg that may be the problem but since I do not think the UMC uses the Neutral I do not think that would matter.

To check this, if you use a volt meter to measure the voltage between each of the outer two rectangular holes and the center one, one at a time, the voltage should be 120. If one is 208 and the other is zero that is your problem. If one is 208 and the other is 120 that could be the problem but I do not think that should matter.

I hadn't even considered that they might be on three-phase delta system. I worked at a business with that and it was very unique (old school with two transformers)... had to pay careful attention to how you hooked circuits up in the panel.

 

[Feathermerchan]

We have a lot of 240V Delta services here. Allows 240V 3 phase and 120/240. Many times the 'lighting pot' or 120/240V transformer is larger than the other two.

 

[eprosenx]

Ooh, this is a fun one!

Lots of comments here:

This very well could be “240v three phase high leg delta” service. It could also be “three phase delta” service which would then be corner grounded or ungrounded, but that is less likely.

The key here is to take a multimeter and measure the voltage on the 14-50 between the two outer pins, and then between each of the outer pins and ground. That is all the UMC cares about. The neutral pin is literally disconnected and connected to nothing. For trying to figure out what is going on though it could be interesting to easier voltage from each of the hot pins to neutral and from neutral to ground.

Can you take pictures of the transformers outside your business and send them to us? They are probably multiple ones on a pole (two or three) or a green box outside the building. I am specifically curious to see the wires coming out of them if they are up in the air.

The idea of bringing your UMC from home is an excellent one - that is a fantastic test.

This should be a solvable issue. Most likely something is wired wrong. Or your Corded Mobile Connector is defective.

Please do report back on a final resolution!

 

[eprosenx]

The more I think of this (re-reading the original post), @davewill is probably right. This is probably a grounding/bonding issue. The original poster describes it as a 208v system which is incredibly common in commercial service.

Voltage readings from each hot pin to the ground pin will tell us a lot. (Along with the other requested readings)