Amps & UMC?

[hjz911]

I am getting my 2014 S 85 delivered next month and trying to get a jump on the charging setup...

I currently own an EV that's juicing off of a dedicated 30a/240v line-charger on a daily bases...

Questions:

#1. Is it ok to install the NEMA 14-50 in place of the current 30a outlet?
#2. I know i'll have to manually set the amp rate to 30a, but will the UMC know that the max charge
should be 24a (80% of 30a)?
#3. Is there a chance that a Tesla Software Update might reset the amp rate to the default (40a)?

Thanks in advance!!

 

[Cosmacelf]

I am getting my 2014 S 85 delivered next month and trying to get a jump on the charging setup...

I currently own an EV that's juicing off of a dedicated 30a/240v line-charger on a daily bases...

Questions:

#1. Is it ok to install the NEMA 14-50 in place of the current 30a outlet?
#2. I know i'll have to manually set the amp rate to 30a, but will the UMC know that the max charge
should be 24a (80% of 30a)?
#3. Is there a chance that a Tesla Software Update might reset the amp rate to the default (40a)?

Thanks in advance!!

The best thing would be to get a Tesla UMC adapter for your 30A receptacle. That way you won’t have to change anything. The Tesla adapter (either for a NEMA 10-30 or NEMA 14-30) will tell the car to draw only 24 amps.

By electrical code, you cannot install a NEMA 14-50 onto a 30A circuit.

Here’s the adapters page: Model S/X NEMA Adapters

 

[BrettS]

#1. Is it ok to install the NEMA 14-50 in place of the current 30a outlet?

Technically it’s possible, but no, it’s definitely not ok. It’s against electrical and is a fire risk.

 

[brkaus]

#1. Is it ok to install the NEMA 14-50 in place of the current 30a outlet?

No, I would just purchase the proper 30A plug from the Tesla store. If you change to a 14-50, you should also make sure the wiring is adequate and the breaker is updated. The wiring is likely not adequate to be safe in case the car does try to pull 40A.

You can purchase a 14-30 (edit: or a 10-30) here -
Model S/X NEMA Adapters

It will automatically set the car to 24a.

#2. I know i'll have to manually set the amp rate to 30a, but will the UMC know that the max charge
should be 24a (80% of 30a)?

No, the car would have to be set to 24a. The setting in the car is exactly what it will pull. Not the full rating of the circuit / circuit breaker. It should be set to 80%... so getting the plug automatically does it!

#3. Is there a chance that a Tesla Software Update might reset the amp rate to the default (40a)?

People have reported updates, resets, etc occasionally resetting the amps. I wouldn't rely on manual amp setting as common practice. Sure, staying at a relatives house for a night and needing a fill-up, ok. But not every day.

Edit again - darn, need to work on my typing speed. @Cosmacelf beat me...

 

[miimura]

If you're already charging an EV, does that mean you currently have a 30A EVSE installed there? If so, you can just use the J1772 adapter that Tesla provides with the car to charge.

 

[hjz911]

Didn't know the NEMA 10/14-30a existed - Guess i should have visited the Tesla store first : )

Thanks so much everyone!!

 

[DriveMe]

#1. Is it ok to install the NEMA 14-50 in place of the current 30a outlet?
#2. I know i'll have to manually set the amp rate to 30a, but will the UMC know that the max charge
should be 24a (80% of 30a)?
#3. Is there a chance that a Tesla Software Update might reset the amp rate to the default (40a)?

For the sake of others who might be reading this thread, it is worth repeating:
No, it is absolutely not ok to install a 14-50 outlet in place of a 30A outlet without replacing all the wires and upgrading the circuit-breaker.

1. This would be a severe code violation
2. You would be running a risk of starting a fire should you forget to set the Amp limit in the car to 24A.
3. And if God forbid you do get a fire, the insurance company will likely refuse to pay anything and you will be liable for all the damages

Just get the proper type of Tesla adapter from the online store. The adapter will automatically limit the Amps to the proper level.

 

[ColdRauv]

If you're already charging an EV, does that mean you currently have a 30A EVSE installed there? If so, you can just use the J1772 adapter that Tesla provides with the car to charge.

EXACTLY! Leave your existing setup and use it for a while to see if it meets your overnight (or other) needs.

 

[hjz911]

Thanks for repeating that DriveMe!! Really important points...

miimura - yes, that will be the next thing - i am currently driving 60-ish miles per day...i would assume with a 24a/17 mile per hour charge - i should be ok to charge the vehicle to 80% every night...Correct me if i am wrong : )

 

[Cosmacelf]

A 24A charge will be more than fine for 60miles a day...

 

[Rocky_H]

The car comes with an adapter for that J1772 charging unit, so you can just use that and not need to change anything or spend any money.

 

[Darmie]

What is the plug type on the charger you use for your current EV? If it is J1772, then as mention there is an adapter that Tesla offers with the car for that plug that goes into the tesla car charging port. In most examples you will see approx 17 plus minus miles each hour on the 30 amp circuit. Simple math, charging over night a 10hour charge is 170 miles back in the tank. Wife and I are living out of town and using the apartment garage 110v which is only 3.5 to 4 miles each hour. Keeping the charge rate at 75 % works perfect for Karen's normal 20-50 miles driving day. Many times we find the car already completed the charged. Point is even at 110V it works out for us within the week.

Oh, and congratulation on the purchase.

 

[hjz911]

Thanks for all your replies!!

I am selling the old charging unit with my EV, so i am left with just the 30a outlet...i went ahead and purchased the 14-30a NEMA adapter...

: )

 

[Rocky_H]

I am selling the old charging unit with my EV, so i am left with just the 30a outlet...i went ahead and purchased the 14-30a NEMA adapter...

You are going to have a complication then. You can't install a 14-30 outlet on that wiring for your old charging unit (probably). The charging units only use the 240V, so if it was a hardwired unit, it only has three wires: hot1, hot2, and ground. You can wire a Tesla wall connector to that seamlessly because that's what it uses too. But a 14-30 outlet is a dual voltage 120/240V outlet type. It requires 4 wires, not 3. So you would have to run an additional wire from the panel, though the wall, to the outlet, and that could be pretty cumbersome and would probably require an electrician. Why are you selling the old unit? Just to get the charge port opening push button of the Tesla charging cable?

*EDIT* Oh, I think I just got this. Your old charging unit wasn't hardwired? It was a unit with a plug that went into an existing 14-30 outlet?

 

[miimura]

Thanks for all your replies!!

I am selling the old charging unit with my EV, so i am left with just the 30a outlet...i went ahead and purchased the 14-30a NEMA adapter...

: )

What is the make and model of your old charging unit? Some of the facts presented in this thread don't make sense.

 

[hjz911]

You are going to have a complication then. You can't install a 14-30 outlet on that wiring for your old charging unit (probably). The charging units only use the 240V, so if it was a hardwired unit, it only has three wires: hot1, hot2, and ground. You can wire a Tesla wall connector to that seamlessly because that's what it uses too. But a 14-30 outlet is a dual voltage 120/240V outlet type. It requires 4 wires, not 3. So you would have to run an additional wire from the panel, though the wall, to the outlet, and that could be pretty cumbersome and would probably require an electrician. Why are you selling the old unit? Just to get the charge port opening push button of the Tesla charging cable?

*EDIT* Oh, I think I just got this. Your old charging unit wasn't hardwired? It was a unit with a plug that went into an existing 14-30 outlet?

Si Senior : ) Thanks for responding!!

 

[ColdRauv]

Si Senior : ) Thanks for responding!!

Or, install a 10-30 outlet and buy the 10-30 plug if it's still offered, and use your UMC.

 

[TexasEV]

Or, install a 10-30 outlet and buy the 10-30 plug if it's still offered, and use your UMC.

Installation of 10-30 outlets hasn’t been allowed for many years. They were replaced by 14-30 outlets.