Tesla HPWC Meter Main Combo

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jfoy

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I have a question regarding adding a 60 amp breaker to this meter main combo. There is a 200 AMP disconnect, and 200 amp sub that is fed through the feed through lugs at the bottom of the panel. There is also a 60 amp breaker for an AC unit. Homeowner would like to add a 60 amp circuit for a Tesla HPWC, but I am unsure if this would be OK with the current setup.
 

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jfoy said:
I have a question regarding adding a 60 amp breaker to this meter main combo. There is a 200 AMP disconnect, and 200 amp sub that is fed through the feed through lugs at the bottom of the panel. There is also a 60 amp breaker for an AC unit. Homeowner would like to add a 60 amp circuit for a Tesla HPWC, but I am unsure if this would be OK with the current setup.
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I don't know what HPWC means; if it is a car charger it would be OK, I believe, but if it's a PowerWall backup battery, that's problematic in several ways.
 
jfoy said:
My concern is overloading the bus bar at the meter main combo. I have the 200 AMP sub panel and the 60 amp AC unit on a 200 or 225 rated bus. Not sure we can add another 60 amp breaker load for the Tesla charger...
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This is where a load calculation is needed.

Just because there is a 200 Amp sub panel breaker doesn't mean the actual load is going to be anything close.

Matter of fact you may want to check to see if 60 AMP is the max breaker size for that AC unit. There may be a small sub panel for a couple of AC units but that large for an AC unit.

That EV charger really isn't going to draw 60 AMPs or at least most don't.
 
growler said:
This is where a load calculation is needed.

Just because there is a 200 Amp sub panel breaker doesn't mean the actual load is going to be anything close.

Matter of fact you may want to check to see if 60 AMP is the max breaker size for that AC unit. There may be a small sub panel for a couple of AC units but that large for an AC unit.

That EV charger really isn't going to draw 60 AMPs or at least most don't.
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5 ton AC usually up to a 60a
 
The 200 amp breaker is the main service disconnect. Not the feed to the sub panel. The sub panel is fed through the feed through lugs on the bottom of the panel in the picture.
 
jfoy said:
The 200 amp breaker is the main service disconnect. Not the feed to the sub panel. The sub panel is fed through the feed through lugs on the bottom of the panel in the picture.
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Yes , we see that. There was just concern that there was other loads on that AC circuit.

The only way to know the extra capacity on that Service is conducting a load calc. There is no shortcut.
 
jfoy said:
My concern is overloading the bus bar at the meter main combo. I have the 200 AMP sub panel and the 60 amp AC unit on a 200 or 225 rated bus. Not sure we can add another 60 amp breaker load for the Tesla charger...
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Really your concern is tripping the main breaker, not overloading the busbar.

For what it's worth, I've never done a load calculation on an existing 200A single family home (using the 220.83 option) that came out over 150A. But you wouldn't want this to be the case that proves my experience wrong.
 
Service limit

Service limit

The fact that you have 200a 240v service to the house doesn't mean you can use all of that thru the Tesla system. Tesla has a circuit limit of 5000watts continuous or 7000w for peaks of less than 10 seconds. What you need to know is how much you are using for existing loads and to do that, get out your last few electric bills, add up the Kwh and average them out to how many Kwh you use in a month, divide by 30 and that's roughly your daily consumption. Ours worked out to around 17kw/day, so for a 24 hours day, our average load is about 710 watts, certainly within Tesla specs. It might shoot up to 5000w when we turn on the electric dryer but it handles it as long as we don't use much else in the house, certainly not the microwave, toaster, coffeepot, hair dryer or other high consumption items. All of those together wouldn't equal 5kw, so if the dryer isn't running, and it only gets used perhaps once or twice a week, the system handles it and the sun recharges the battery, if you do this early enough in the day. According to the Tesla app, our household consumption is more like 13Kwh/day, not 17, as the power company's meter says. I trust the Tesla app to be more accurate...every amp the house uses passes through the gateway,whether it's coming from the panels, the battery or the grid or some combinatgion, and is easy enough to measure.

If your average loads exceed or are near this 5Kw limit, you'll might consider installing breakers to kill certain circuits when you are using the Tesla as a grid backup, or just don't turn certain stuff on, or shut if off if it's something like an electric water heater which you have almost no control over when it turns on and off. A/C on a Tesla system is pretty iffy...better be an efficient inverter split system and don't run it all day.

Good luck
 
caribconsult

You do realize this is a Tesla car charger not a power wall. All that is required is a residential Load Calc.
 
No, I obviously missed that part about it being a car charger. Sorry. I don't see anything in the post that specifies car charger, the poster just says 'charger' and I assumed he meant the charging section of the Powerwall.
 
caribconsult said:
No, I obviously missed that part about it being a car charger. Sorry. I don't see anything in the post that specifies car charger, the poster just says 'charger' and I assumed he meant the charging section of the Powerwall.
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Post number 1

"Tesla HPWC"

:ashamed1:
 
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