HPWC Installation Quote Flexibility

[MightyHawk]

I just received a quote to install a HPWC in my home, for $1000 plus the cost of the HPWC. This quote included putting in a 60 amp breaker and wiring.

But rather than just wire up just the HPWC, I would instead like to install a sub-panel in the garage and ideally connect that to the main panel using a 100 amp breaker, and then wire the HPWC to as high an amperage as possible.

Is it typically possible to renegotiate work with the electrician upon arrival? Or do they simply just do that work?

 

[justsomeguy]

I just received a quote to install a HPWC in my home, for $1000 plus the cost of the HPWC. This quote included putting in a 60 amp breaker and wiring.

But rather than just wire up just the HPWC, I would instead like to install a sub-panel in the garage and ideally connect that to the main panel using a 100 amp breaker, and then wire the HPWC to as high an amperage as possible.

Is it typically possible to renegotiate work with the electrician upon arrival? Or do they simply just do that work?

Maybe call them? I can't see them turning down extra work. I doubt you can just tell them when they show up though, unless they just happen to have all required material.

 

[ewoodrick]

At a bare minimum, would they have the correct parts? Probably not. Then of course the question is if your panel can handle it.

By the way, setting the HPWC to as high as possible isn't a great use for a Model 3. It can't use it all.

 

[MightyHawk]

By the way, setting the HPWC to as high as possible isn't a great use for a Model 3. It can't use it all

I know that the Model 3 can only pull 48 amps. However, my understanding is that wiring up the HPWC at a higher current won't damage the Model 3 as the Model 3 will negotiate its current draw. And a higher current can be useful for any future Teslas.

 

[jmaddr]

Changing from 60A to 100A and adding a panel will increase your cost as the wiring gauge will have to be increased and a new panel installed but it's completely doable as long as the electrician knows beforehand so he can bring the different wiring, sub-panel, and additional breakers. Furthermore, your service would need have some load calculations done to support the extra 100A load if you have plans on actually that 100A. Heck, if your main service is already at capacity, a load calculation should be done to make sure it can handle the additional 60A. Load calculations at peak load would need to be done.

However, as @ewoodrick states, it's a complete waste of money unless:
- you have plans to add a second Tesla HPWC (for a second car) and charge off the same circuit
- you have plans for that second breaker panel for something else

 

[MightyHawk]

I have at least two more circuits to wire in the garage. The first is for a space heater (our master bathroom is above the garage and the pipes sometimes freeze). The second is for an upcoming car lift...

 

[ZOMGVTEK]

Most guys won't have the materials on hand for a change like that. They either buy it at the start of the day, or bring what they need with them. Making a change like that isn't very challenging, but they'd likely want to know about it before they show up.

There's no issue with running larger wire to the wall connector. The wall connector is just a fancy extension cord and tells the car how much power it can draw. It's not unreasonable to oversize the conductor a smidge, but there's really not much in it running it on a 100A breaker. And if you have 100A service, definitely don't even bother running the wall connector on a 100A breaker. Personally i'd say run #4 THHN in EMT with a 60A breaker. But running a 100A sub to the garage is totally reasonable.

 

[Plu1357]

$1,500 is about right.
This is what I have done and shaved $800.

1. Purchased a Tesla Wall Connector. $500
2. Run 6/2 Romex wire for more than 100ft. $150
3. Install 60A breaker to my 200A panel.$50

(Just a reference. not a tutorial)

 

[SSedan]

Higher amperage install might be useful for a friend or a future EV.

 

[MightyHawk]

This is what I have done and shaved $800.

I am an electrical engineer by training, although I haven’t used that knowledge in a while.

Still, I estimate that I have a 99 percent chance of doing this myself and not burning the house down or electrocuting myself. I don’t consider those very good odds.

 

[Sophias_dad]

I am an electrical engineer by training, although I haven’t used that knowledge in a while.

Still, I estimate that I have a 99 percent chance of doing this myself and not burning the house down or electrocuting myself. I don’t consider those very good odds.

Perhaps another option to consider.... get a new electrician, and park your Tesla somewhere far from the house the day he comes to quote and eventually install a new 100amp subpanel in your garage, for your new lift, some new lighting, a pool heater, pool pump, and so on... Do not let him know there's a tesla involved. Get him to do the work to get your 100 amp subpanel in place, and then swoop in after he's gone with $100 in parts to connect your HPWC.

It would be pretty bad form to wait for your original electrician to come in to tell him you want a subpanel, even if he has the wire and panel and breakers on hand. 100 amp wire is some pretty hefty stuff, and can get pretty pricey if there's any serious length to it.

 

[MrMassTransit]

Yeah, I would second the recommendations of others and just give them a call and ask them to modify their quote for the 100A subpanel. I have charging installed in an outdoor parking space in the parking lot of my condo. After the original quote, I decided that I wanted to add a 120v outlet to the install so I had easily accessible power out where I park the car. This necessitated the install of a subpanel and an additional hot and neutral wire in the conduit that runs out the space. I just called the electrician and he revised the quote and brought the appropriate parts with him on the day of the install. Was easy enough and I've been very thankful I had the install done the way I wanted.

 

[Yeldah]

My quote from Tesla for a HPWC was $2500. $1000 of that was for conduit. For less 14 feet of conduit. I contacted a local electrician and he says he can do it all for under $500 plus the cost of the charger. So that is around $1000 total. This will save me $1500. I suggest contact a local "Honest" electrician and depending the work could save you a lot of money. He is installing a 100A breaker as well.