Home install help

[Hunter]

I spoke with my electrician. So to clarify, we have a 200A main box with 90A coming to the house sub-panel. He can't pull anymore because the rest is being used by our upstairs and downstairs HVACs (2 separate units).
He wants to run a 60A breaker off of our house sub-panel to the charger and then pull 48A (with the charger setting on 5).

Thoughts?

(And thanks for everyone's input)

Sponsored

 

[tls]

The main breaker is 90A. And yes, he thinks pulling more than 60A will trip the main house breaker. He said I may have to be careful about running our dryer when charging my truck if we push it too high.

Is your service entrance shared with another dwelling unit? Is your wiring very old? If not, I think it's important to understand *why* your panel has a 90A main breaker, on a 200A service from the utility.

If there is no reason other than the rating of the panel itself - some small/cheap panels that are mostly used as subpanels are in fact rated for only 125A though I'm not sure I've ever seen a panel rated for 90, it's kind of an odd size - then the right answer is really a new panel with a 200A main.

 

[Yellow Buddy]

I spoke with my electrician. So to clarify, we have a 200A main box with 90A coming to the house sub-panel. He can't pull anymore because the rest is being used by our upstairs and downstairs HVACs (2 separate units).
He wants to run a 60A breaker off of our house sub-panel to the charger and then pull 48A (with the charger setting on 5).

Thoughts?

(And thanks for everyone's input)

With enough money, anything is possible. I’m saying that because I don’t know your exact situation and the labor prices could vary wildly. So take what I’m about to say with a grain of salt.

If it was me, I’d get a 2nd and 3rd electrician in to get their opinions.

The reason for that would be because this electrician seems to be really driving towards the 60A solution, 48A in my opinion is plenty to keep the truck topped off but if I wanted 80A; wouldn’t be meeting my needs.

Additionally the 90A home panel is going to use 30A for the dryer (likely 20A actual use) 48A for the charger that’s 68A before you factor in any kitchen appliances. A single 1500W toaster oven for example is 12A. It’s doable, but probably just closer than I would like.

Your 200A panel, I’m not sure what’s on it. But the panel can be upgraded. You can even throw in new breakers to create room, you can install a 100A subpanel and consolidate your HVAC to create the room. There’s a lot of options that vary in cost, which is why I would talk to several electricians so you can compare and weigh the cost based on what’s important to you.

How set are you on the 80A? Are you comfortable enough that if you trip breakers to go and reset it? If not and this is the cheapest solution, I’d recommend turning it down to 40 or 32A if you don’t want to deal with nuisance trips. It takes longer to charge but depending on your EV usage that might be even ok.

Just to be clear though, you don’t have a true capacity issue. You have a design issue that is limiting your capacity. Designing it improperly can lead to future capacity issues and it is my opinion that hooking it to your house panel is the easy way out and does not appropriately give you the current capacity you need while leaving room for the future upgradeable capacity that you might need (Ie, 2nd EV charger, kitchen remodel, etc)

 

[tls]

That part about "there isn't any available amperage to pull off of the main breaker" is the part that doesn't make sense. I am sitting in a 3 story home with a heat pump (30A) as the only source of heat, a hot tub rated at 50A, electric kitchen, washer/dryer, two electric hot water heaters, lighting loads, even an old steam shower, and 200A service, with 72A of charging loads running (simultaneously charging the Lightning and our Model Y) and we're not anywhere near tripping the main. Not even last week when it was -16 at night.

Charging loads are continuous but all those other house loads? They aren't. For example, a heat pump on a 30A breaker might draw 30A for a tiny fraction of a second as the compressor starts but then it drops down to far less - 10A or so - while it runs. Because they really are never all drawing max current simultaneously the total of the breaker sizes in a panel can add up to far more than the size of the main. Unless you have multiple kitchens and laundries, a ceramics kiln, electric baseboard heat (only!) in a cold climate, etc. it is really unlikely that you do not have enough service on 200A for your air conditioners, your other house loads, and an 80A charger. Your electrician may have in mind the size of the existing feeder wiring between your panels, or be trying to save you expense or disruption involved with getting heavy wire from your main panel to where you park, but - 200A is enough service. It is possible, if there is not some additional misunderstanding, that you might want to consult an electrician more experienced in estimating loads.

One last thing worth checking is that some older air conditioners have particularly high starting ("inrush") current which can be reduced by replacing their starter circuitry (sometimes called the "starting capacitor" though it's not actually just that). This can allow replacing 30A air conditioner breakers with 25A (yes, they exist) or even in some cases 20A. Perhaps if that is possible it would make your electrician more comfortable pulling additional current from the actual 200A main panel.

 

[GDN]

I spoke with my electrician. So to clarify, we have a 200A main box with 90A coming to the house sub-panel. He can't pull anymore because the rest is being used by our upstairs and downstairs HVACs (2 separate units).
He wants to run a 60A breaker off of our house sub-panel to the charger and then pull 48A (with the charger setting on 5).

Thoughts?

(And thanks for everyone's input)

If 48 amp charging meets your needs I see no need to spend any more money on the solution. 200 amp panels are the standard here in TX and are more than adequate to support AC, pools, electric ovens and car charging.

There is nothing wrong with having the sub panel. It sounds like the electrician that installed it and your current electrician believe there is plenty of juice in the main panel to support what is there and still have the sub panel with a 60 amp breaker and run our charger at 48 amps, then you have the right solution.

Very few need any more charging that than on a daily basis. In 8 hours you can easily add 160 miles to the truck. Only if you are driving more than that on a daily basis should you consider anything further.

 

[Yellow Buddy]

That part about "there isn't any available amperage to pull off of the main breaker" is the part that doesn't make sense. I am sitting in a 3 story home with a heat pump (30A) as the only source of heat, a hot tub rated at 50A, electric kitchen, washer/dryer, two electric hot water heaters, lighting loads, even an old steam shower, and 200A service, with 72A of charging loads running (simultaneously charging the Lightning and our Model Y) and we're not anywhere near tripping the main. Not even last week when it was -16 at night.

Charging loads are continuous but all those other house loads? They aren't. For example, a heat pump on a 30A breaker might draw 30A for a tiny fraction of a second as the compressor starts but then it drops down to far less - 10A or so - while it runs. Because they really are never all drawing max current simultaneously the total of the breaker sizes in a panel can add up to far more than the size of the main. Unless you have multiple kitchens and laundries, a ceramics kiln, electric baseboard heat (only!) in a cold climate, etc. it is really unlikely that you do not have enough service on 200A for your air conditioners, your other house loads, and an 80A charger. Your electrician may have in mind the size of the existing feeder wiring between your panels, or be trying to save you expense or disruption involved with getting heavy wire from your main panel to where you park, but - 200A is enough service. It is possible, if there is not some additional misunderstanding, that you might want to consult an electrician more experienced in estimating loads.

One last thing worth checking is that some older air conditioners have particularly high starting ("inrush") current which can be reduced by replacing their starter circuitry (sometimes called the "starting capacitor" though it's not actually just that). This can allow replacing 30A air conditioner breakers with 25A (yes, they exist) or even in some cases 20A. Perhaps if that is possible it would make your electrician more comfortable pulling additional current from the actual 200A main panel.

Based on the convo, I don’t think it’s the available amperage. I think the main panel is out of slots. The electrician doesn’t want to include a panel upgrade because it would need to pull the meter and likely require 2 trips to install. 1 to wire, 1 to meet electric company to pull. If he runs it from the home panel it’s 1 trip and done.

But there are ways to do this, if there’s 4 slots dedicated to the HVAC, I’d spend the $ for a panel, conduit, etc and use 2 of those slots to put those 4 in a new panel. Freeing up 2 slots. I’d then use the 2 newly free’d slots to run a dedicated garage panel.

Total materials would be roughly $300-500 depending on quality of materials but there would be more labor but still a 1 trip install.

 

[Toby57]

Maybe I can help here. OP's post #16 above explains it.
Post #16
A. His house has a 200A service. Probably has a 200A main breaker.
B. His main panel feeds his two HVAC systems. (probably a large load)
C. There is also probably a breaker in the 200A panel feeding a sub panel. What he is calling a house panel.
D. His electrician wants to pull out of this sub fed panel to wire his charger.
Hope that helps
Edit to add.
A 60A circuit is a 60A circuit. If his electrician thinks his service can handle it, it probably can. It really does not matter which panel he pulls it from. In this case the sub fed probably cheaper and not a heavy load . Just a guess.

 

[Toby57]

From post #1.
OP states he has 200A main.
His electrician says he only pulls 90A on main.
I have no idea what Amp is feeding his sub panel. His electrician must think there is enough there for a 60A circuit.

 

[GDN]

OK @Hunter - Time to draw us a picture

 

[GDN]

Maybe I can help here. OP's post #16 above explains it.
Post #16
A. His house has a 200A service. Probably has a 200A main breaker.
B. His main panel feeds his two HVAC systems. (probably a large load)
C. There is also probably a breaker in the 200A panel feeding a sub panel. What he is calling a house panel.
D. His electrician wants to pull out of this sub fed panel to wire his charger.
Hope that helps
Edit to add.
A 60A circuit is a 60A circuit. If his electrician thinks his service can handle it, it probably can. It really does not matter which panel he pulls it from. In this case the sub fed probably cheaper and not a heavy load . Just a guess.

This is what I thought had been explained as well, but I think only a picture will clarify this right now.

 

[Toby57]

A picture? Maybe.I will say this to the OP. Your electrician has had eyes on. He knows best for your situation. More so than me or anyone else on these forums. If in doubt, call another electrician and see if they say the same thing as the first electrician.

 

[Toby57]

This is what I thought had been explained as well, but I think only a picture will clarify this right now.

You did say it in post #20,. My bad.

 

[GDN]

You did say it in post #20,. My bad.

No problem - I'm not claiming it first, I'm just agreeing with you. Thinking since several of us are interpreting it differently a picture will clarify.

You are also correct though - the electrician with his hands on is the one that should know and make the decision of what is possible.

 

[Toby57]

No problem.

 

[Hunter]

Do yall know if the charger has to run on a 100 amp breaker to operate properly like the manual recommends, or can it run on a 60 amp breaker and then the charger be dialed back to accommodate the amount of current fed to it?

Sponsored