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Electrical Engineer / Contractor Question: Garage Level 2 Charging cord set-up Question

In my garage, I have a 220V electric dryer that I want to share the output with my Tesla Mobile Charger for level 2 charging. I just ordered and intend to plug in an UL Listed NeoCharge splitter (NeoCharge Smart Splitter) to my garage dryer 10-50 outlet. My fuse box and dryer is set up with a 30A fuse. My dryer also has a 10-50 plug.

Since NeoCharge can only sell their units with 2 10-50 inputs, I need to attach a 10-50P 50A to 10-30R adapter (AC WORKS 10-50P 50 Amp 3-Prong Old Style Dryer/Range Plug to 10-30R 3-Prong Dryer Outlet-AD10501030 - The Home Depot). I realize my Model 3 car charger has a chip that automatically controls charging current so that my car cannot charge faster than it is safe but I don't really know for sure if this will work.
Question for an experienced electrical engineer / contractor: Will this work safely?
Thank you for your help..
 

Tam

Well-Known Member
Nov 25, 2012
10,762
9,802
Visalia, CA
In my garage, I have a 220V electric dryer that I want to share the output with my Tesla Mobile Charger for level 2 charging. I just ordered and intend to plug in an UL Listed NeoCharge splitter (NeoCharge Smart Splitter) to my garage dryer 10-50 outlet. My fuse box and dryer is set up with a 30A fuse. My dryer also has a 10-50 plug.

Since NeoCharge can only sell their units with 2 10-50 inputs, I need to attach a 10-50P 50A to 10-30R adapter (AC WORKS 10-50P 50 Amp 3-Prong Old Style Dryer/Range Plug to 10-30R 3-Prong Dryer Outlet-AD10501030 - The Home Depot). I realize my Model 3 car charger has a chip that automatically controls charging current so that my car cannot charge faster than it is safe but I don't really know for sure if this will work.
Question for an experienced electrical engineer / contractor: Will this work safely?
Thank you for your help..
Most home dryers are 30A, and not 50A so I am surprised that your dryer has 10-50 plug.

Anyhow, since your breaker is 30A, the dryer outlet should also be 30A and not 10-50.

So, I would convert your outlet to its appropriate 30A and not 50A to work with your 30A breaker.

The smart splitter does come with 30A versions for home dryers. Use it.
 
Thank you Tam. Yes, 30A is the dedicated fuse in the fuse box; the odd 10-50 plug was what was "installed" on the Sears dryer and the wall output before I bought my home 30 years ago. I haven't touched the electrical wiring at all. Outside of changing light bulbs to LED and attaching some extension cords in our home, this my first attempt at anything remotely electrical.. I don't wanna guess which is why I put this out here. Thanks again. Wish me luck!!
 

Tam

Well-Known Member
Nov 25, 2012
10,762
9,802
Visalia, CA
...I realize my Model 3 car charger has a chip that automatically controls charging current so that my car cannot charge faster than it is safe...

Your car sets its maximum Amperes according to the adapter and the car's charger limit, whatever lower.

So your car's charge limit is maximally at 42A (the older Model S is 80A).

If you plug a Tesla 50A adapter on your mobile charger, your car would set its limit to 42, instead of 50.

The problem is your breaker is 30A and your car sets its charge limit beyond that, which is 42.

Thus, in this case, if you got a good breaker, the breaker would shut down the charge and if your breaker is too old and not reliable, there might be an electrical fire.
 

Sophias_dad

Active Member
Supporting Member
Jul 29, 2018
2,188
2,469
Massachusetts
Your car sets its maximum Amperes according to the adapter and the car's charger limit, whatever lower.

So your car's charge limit is maximally at 42A (the older Model S is 80A).

If you plug a Tesla 50A adapter on your mobile charger, your car would set its limit to 42, instead of 50.

The problem is your breaker is 30A and your car sets its charge limit beyond that, which is 42.

Thus, in this case, if you got a good breaker, the breaker would shut down the charge and if your breaker is too old and not reliable, there might be an electrical fire.
Much of this is incorrect information. The 3's charge rate limit is 48 amps if its long range, 32 amps if its short range. The UMC that came with the car will NEVER charge faster than 32 amps, regardless of the adapter on it.

IMHO, OP should change the outlet to a 14-30 or somesuch and get whatever smart splitter will change that single 14-30 into a pair of 14-30's. Better yet, run a new line and just stick a new HPWC on the wall, which will cost the same as a NeoCharge, it seems. I realize there's times when such things are simply impossible, though.

OP's plan to use the 10-50>10-30 adapter should be entirely 'safe', in that the 10-30 adapter for the UMC will keep the charge level down at 24 amps(30x80%)
 

SageBrush

REJECT Fascism
May 7, 2015
13,275
18,039
New Mexico
So far as I can tell, the 10 - x series is hot,hot, neutral.
Our EVSEs expect hot,hot, ground

The old style dryer plugs were 10-30, meaning 30 Amp breaker, hot,hot,neutral conductors
A 10-50 receptacle on a 30 Amp breaker is asking for trouble, and it violates NEC severely

OP is being silly asking for free EE advice, but it sure would be advisable for him to have an electrician come sort things out.
 

SageBrush

REJECT Fascism
May 7, 2015
13,275
18,039
New Mexico
IMHO, OP should change the outlet to a 14-30

Not if the dryer is 10-30, and the old receptacle implies that the non hot conductor is connected to the neutral bar in the panel.

This entire story is a cluster***f, and OP will make it worse if he makes do with internet advice.
 
Last edited:

Rocky_H

Well-Known Member
Feb 19, 2015
7,853
9,884
Boise, ID
IMHO, OP should change the outlet to a 14-30
Not if the dryer is 10-30, and the old receptacle implies that the non hot conductor is connected to the neutral bar in the panel.
That is what the word "change" means. It is to make it not like it was before. If all four wires are there, you can change a 10-30 to a 14-30 properly. And yes, that would include adjustment of the wires at the other end in the panel too.

A 10-50 receptacle on a 30 Amp breaker is asking for trouble, and it violates NEC severely
Well, it doesn't. That is the direction you are allowed to go. The outlet can be higher rated than the breaker--not the other way around. But it's not allowed to put in new 10-XX type of outlets now anyway, so that specific example still couldn't be done for a different reason.
 
Think the best thing is to properly label this outlet 30A and run a separate EVSE and leave the dryer as is. But that might not be doable. I have to assume converting to a 14-30 isn’t possible either as I highly doubt they ran a neutral. Seems the next best bet would be to install a 10-30 plug, get the 10-30 neocharge, replace the dryer plug to a 10-30, buy the 10-30 UMC adapter. While probably the right way, that’s expensive too. Doing it with 10-50 neocharge and a plug changer would probably work fine, however I’m not a huge fan of permanent adapters and I’m pretty sure Tesla and Neocharge would say you shouldn’t. If it was me, I would probably do all I could to just install an EVSE. OP have you looked to see if rebates are available from your Electrical company?
 

SageBrush

REJECT Fascism
May 7, 2015
13,275
18,039
New Mexico
That is what the word "change" means.
Fair enough. I read that other post as suggesting work only at the receptacle, and I wanted OP to be clear that would not be enough.

If all four wires are there
Yes

Well, it doesn't. That is the direction you are allowed to go. The outlet can be higher rated than the breaker--not the other way around.
I stand corrected, and your statement makes sense. I still would not do it though, since it would encourage people to try and pull more than 30 Amps, or worse case replace the breaker to match the receptacle without knowing if the conductor can carry the higher load.
 

smatthew

Active Member
Jun 9, 2018
1,460
2,438
CA Bay Area
Wait, there's an easy solution! Cut the leg off the L shaped pin. And by "cut the leg off" I mean convert the pin from an L shape, to the straight shape of a 10-50.
Look at a 10-30 vs 10-50.
The 10-30 will then easily fit into a 10-50, but limit it to 10-30 rates!

I may or may not have had to buy a hacksaw at the local hardware store while on a vacation trip xmas before last....
 

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