220V outlet spliced from water heater line?

[proudapron]

I've got a friend who is looking at a M3 and doesn't have any affordable/easy way to add 220V charging in his garage. His water heater is in the garage and is set to run on a timer. Charging 110V is out of the question since his commute is about 75 miles.

What do you guys think of the idea of having him splice the 220V line that goes to the water heater from the wall with a junction box so he has a 220V wall plug and water heater connections? He could set his M3 to charge during the times the water heater is off or reduce the amps when the water heater is on.

 

[Dannno]

Not a good idea. Check out "Dryer Buddy".

 

[Fernand]

It's all a matter of how competently the job is done. It's not rocket science, but it IS a lot of current. A lot of people don't have any idea of required wire thickness, voltage drop, ignition temperatures of common building materials, fire extinguisher types, homeless shelters, etc. Ideally someone with experience would supervise the project.

 

[jjrandorin]

I've got a friend who is looking at a M3 and doesn't have any affordable/easy way to add 220V charging in his garage. His water heater is in the garage and is set to run on a timer. Charging 110V is out of the question since his commute is about 75 miles.

What do you guys think of the idea of having him splice the 220V line that goes to the water heater from the wall with a junction box so he has a 220V wall plug and water heater connections? He could set his M3 to charge during the times the water heater is off or reduce the amps when the water heater is on.

bad, bad idea. EV charging is supposed to be a dedicated line, and depending on "a human" to "always remember" to turn down amps is a recipe for failure. EV charging uses more power than almost anything else in a regular house, and power = heat.

The most economical thing is to get an electrician to add some sort of 220v outlet and then buy the appropriate adapter for it. doesnt have to be a 14-50, could be a 40 amp circuit or even 30 amp. Can tell an electrician its for some equipment, etc.

 

[David_Cary]

It can absolutely be done safely.
One option is to convert the water heater to 120V. I did this to limit peak demand when I had a demand charge. As long as your tank is fairly large, it is fine.
The other option is to have a dryer buddy type device.
But - honestly - I would try the 120V option for the water heater. It will kill the recovery but most people don't really need what they have unless the household is large.

I don't also see why you can't do 120V for the car.
Start week at 300. Recover 50 miles per night at 10 hours/5 mi hr.
Tuesday - awake to 275. By Friday, you are at 200. 125 mile butter.

You can also try using 2 120V on opposite phase - can't remember the product that allows that.

Who the heck commutes 75 miles? 5 days a week? And to what? - live in a house that doesn't even have a proper electrical panel. I presume this isn't the way he/she wants to live his life so it will be temporary.

Lastly - the 120V water heater is even easier in an AZ garage. Most of the time ambient is as hot as the tank and I am guessing the ground water temp is 80+.

 

[RayK]

It can get pretty cold in AZ, depending on the location.

Additionally, 5mph charge rate using 120V is absolutely ideal conditions. Figure more like 3-4 if you have to use an extension cord.

 

[ucmndd]

Who the heck commutes 75 miles? 5 days a week? And to what? - live in a house that doesn't even have a proper electrical panel. I presume this isn't the way he/she wants to live his life so it will be temporary.
.

More than a million people in the US alone commute 75+ miles one way. About 8% of working Americans travel ~75 miles round trip - and plenty of people have perfectly valid reasons for it.

About That Commute - HR Daily Advisor

OP, I agree with most others this is a bad idea. Don’t hack together something stupid to save a few hundred bucks.

 

[Hblick48]

Not a good idea. Check out "Dryer Buddy".

X2. Works great. No electrician needed.

 

[David_Cary]

I was figuring not enough room on the panel - thus way more than a few hundred $$. Can be more like $5000.
Why would you need an extension cord in a garage?
The majority of AZ lives in a warm climate. In fact, it is pretty much the hottest state in the country. So, sure, some areas of AZ get cold, but most people live in areas that are not.

More than 8% of people think Donald Trump is a great president. So just because 8% of Americans do something doesn't make it a reasonable thing to do. But fair point that there are reasonable reasons to do it. I would never do it - permanently and for 5 days a week. That is just me (and the issue is irrelevant and for that I apologize.)

For a few hundred dollars - the OP's friend should just do it. I am willing to bet a few hundred dollars that this is not the case.

 

[proudapron]

Lots of great comments both ways so far, thanks for tip on the dryer buddy too! The problem isn't the commute alone, it's the commute plus the daily driving around. That could easily add up to 100+ miles per day, range that just can't be easily recovered on a 110v outlet. And before any of you suggest they use their other car for daily driving you have to remember: isn't part of the joy of having a Tesla to drive it?

Anyway, I would make sure to tell him to do homework on the wiring and other components first. The challenge is his main panel is on the other side of the house and his dryer is upstairs. 220V wouldn't just come easy which is why him and I had the water heater idea.

I'll check with him what amperage his breaker is to see if they can even share the load (if it's 50A that would be fine right?)

 

[ucmndd]

(if it's 50A that would be fine right?)

This isn’t the right question to be asking - it depends on what the water heater can draw.

At any rate, the proposed hack is almost certainly against code and asking for problems.

If I was looking for cheap ways to get a 240v circuit (note, not 220v, nominal voltages in North America have been 120/240 volts for nearly a century), my first option would be to determine if it’s feasible to convert an existing 120v wall plug
circuit to 240v - replace the breaker in the panel with an appropriately sized 15 or 20 amp (depending on wire gauge) double pole, then replace the receptacle(s) with 6-15 or 6-20s.

A 6-15 outlet isn’t the fastest thing in the world but would give you 11 mph on a model 3, which should be enough for most use cases. 15 mph if you’ve got 12 gauge wire and can do a 6-20.

 

[proudapron]

Good idea! Convert the 120v to 240v at the breaker if there's room and double the output. The only thing would be finding all the other outlets on that string and swap them out for wall plates so nobody plugs into 240v on accident in the house.

I'll let him know of all these ideas, keep them coming thanks!

 

[timk225]

How is he going to splice into something that does not exist? If he is in America, there is no such thing as 220 volt power. We have 240 volts.

 

[msm859]

I've got a friend who is looking at a M3 and doesn't have any affordable/easy way to add 220V charging in his garage. His water heater is in the garage and is set to run on a timer. Charging 110V is out of the question since his commute is about 75 miles.

What do you guys think of the idea of having him splice the 220V line that goes to the water heater from the wall with a junction box so he has a 220V wall plug and water heater connections? He could set his M3 to charge during the times the water heater is off or reduce the amps when the water heater is on.

No problem get a switch so that only one appliance can draw a load at one time.

 

[TwoK4drSi]

https://www.getneocharge.com/

 

[EnrgyNDpndnce]

No problem get a switch so that only one appliance can draw a load at one time.

Yep, exactly what we did because we have a detached garage. Put a transfer switch in at the dryer (back of the house closest to the garage) and ran 240 out to the garage from the switch. So we can either power the dryer or the charger at any given moment, but never both. OP could do same with water heater.

 

[iwannam3]

Dryer buddy is for plug in appliances that run interminably. A water heater is not a plug in appliance. It will also draw full amps for long periods continuously unlike a dryer or welder or air compressor. The charger will also draw power continuously while it is on. Not worth burning the house down.

 

[DaveRZ]

I actually talked a co-worker out of a TM3 who didn't have a good way of charging at home and she was going to rely on superchargers and 120V outlets at her friend's house.

TO ME (feel free to think differently), BETTER THAN ADEQUATE charging at your home or work is required before making a commitment to an electric car. Relying on public charging takes one of the best features of an EV and turns it into a negative... ...again, in my opinion. I know there are plenty of folks who do this, but to me it defeats the main benefit of going electric.

That being said, if you install a switch that only allows power to one at a time, you should be able to safely tee off the line and install a 6-20 outlet (and appropriate 20 amp breaker, of course). I'm guessing the original circuit will be around 25 amps or so. Of course, this means that your friend's hot water will be a bit cool in the morning in time for showers, and he'll need to trudge out to the garage and flip the switch back to get the WH going.

 

[Sophias_dad]

https://smile.amazon.com/Intermatic...child=1&keywords=T7802B&qid=1595766985&sr=8-1

Probably better, certainly cheaper...

https://smile.amazon.com/dp/B0055P4L7I?tag=duckduckgo-exp-b-20&linkCode=osi&th=1&psc=1

But in reality, neither of these options are a great idea... I imagine the electrical code says the water heater is supposed to be on its own private circuit, and the EV is also supposed to be on its own circuit(although you could argue its just an outlet, not an EV). Either of these would keep the house from burning down, though.

 

[vjason]

If I remember correctly 120V charging isn’t as efficient either, less power into the batteries per watt hour than 240V.

Plus homeowners policies love it when you do shady electrical work and try to make a damage claim. Saves them a lot of money.