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90 or 30 amp circuit breaker for charging?

rhino2627

Member
Mar 31, 2016
38
9
Elmhurst, IL
Current Model 3 owner and in the process of building a house. I suggested to the builder that I wanted a 90 amp circuit breaker that would run to 3 charge ports in the garage. I'll only have 1 Tesla Wall Connector at the outset, the others will terminate and I'll install other wall connectors if/when I purchase other electric vehicles. Basically I'm trying to future proof my charging needs.

My builder suggested going with only a 30 amp breaker and a Bosch 30 amp charger, this way I wouldn't tie myself to one brand of vehicle (which I agree with).

Does anyone have any experience with the Bosch Power Max 30 amp charger? Can it be installed to a 90 amp circuit? Am I missing anything?
 

Lloyd

Well-Known Member
Supporting Member
Jan 12, 2011
6,324
2,125
San Luis Obispo, CA
You will have to use an adapter every time you charge with the Bosch. I suggest putting a 50 amp 14-50 and use the HPC that comes with the car. You can then upgrade to a 60 amp HPWC later with the same #6 wire.

A 1" conduit will allow you to pull larger wire later if you feel the need. I charge two tesla's on a 60 amp circuit and it is plenty for overnight charging.
 
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Derek Kessler

Active Member
Apr 15, 2016
1,193
1,806
Cincinnati
Universal option: If you want maximum flexibility, you could install multiple NEMA 14-50 plugs (50 amps), each on their own circuit. It might cost a bit more, but you'll get (1) more power, (2) adaptability to whatever charging standard you want to use today and in the future, and (3) if you ever move you can just unplug and take your charger with you. Slap a shelf or box or hooks or something on the wall next to each receptacle to hold the connector hardware, cables, etc.

Tesla-only option: You can run the single 90-amp line and put multiple Tesla Wall Connectors on it. They'll communicate and load balance between them when charging multiple vehicles.
 

barjohn

Member
Sep 23, 2017
547
668
Riverside, CA
I would go with a 100A breaker and the three circuits. Much less expensive to do now than add in the future. This means you probably need a 300A panel. You can use the Tesla Wall Connector with an adapter for J1772 for other vehicles and their charger allows you to set maximum charge level for each connector individually. You need to set it higher than the max charge rate for the vehicle. The vehicle will never charge at a rate higher than its internal charger max rate. The cost for the Tesla Wall chargers is running around $400 on eBay for new ones. They (WCs) are excellent units. The Bosch chargers are over $800 for a 30A, a ridiculous price, you can get up to 80A with a Wall Connector.
 

boaterva

Supporting Member
Supporting Member
Apr 2, 2016
7,574
3,746
Northern Virginia, USA
If you want to run multiple HPWC's you don't want to run a 90, you want to run a 100, which will have a max 80 to one HPWC and load balance/share to the others. With two cars, it would give each one 40. Why not have the max power available for a few bucks more.

And, as was said, are you planning for Teslas or for other cars? For yourself or for other people? :D

And see my sig for Flasher's excellent sig and photos of my install.

I see barjohn and I had the same thought at the same time!
 

brkaus

Well-Known Member
Jul 8, 2014
8,057
6,551
Austin, TX
If price isn't terrible, I would do 100A to a sub-panel in the garage. With conduit going from there to the three garage locations. Initially put in a 50A breaker and a 14-50... with appropriate wire gauge for a 60A breaker.

I would NOT bother with a 30a EVSE. Worst case, put in a 14-50 as mentioned above. And make sure it is wired to accept a 60a breaker in the future.
 
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edlin303

Member
Jan 29, 2018
103
110
San Diego
Definitely don't go too small. 30a may be ok for overnight charging if you don't drive a lot, but it is very slow, and if you are ever in a rush you will regret it. I would do the following:

Run 100A to a box, connect HPWC today, but be sure how you wire it is compatible with the load-sharing HPWC setup.
- If you end up going Tesla, add another HPWC do a load-sharing setup and both can use max charging if the other is not charging
- If you end up needing to change to non-tesla, then you could add a new 50A later, or add a sub-panel that breaks the 100A into a couple of smaller circuits, one for your HPWC and the other for an EVSE like Clipper Creek, Bosch, etc.
 

Big Earl

bnkwupt
Supporting Member
Jul 12, 2017
5,835
10,822
Springfield, VA
Current Model 3 owner and in the process of building a house. I suggested to the builder that I wanted a 90 amp circuit breaker that would run to 3 charge ports in the garage. I'll only have 1 Tesla Wall Connector at the outset, the others will terminate and I'll install other wall connectors if/when I purchase other electric vehicles. Basically I'm trying to future proof my charging needs.

My builder suggested going with only a 30 amp breaker and a Bosch 30 amp charger, this way I wouldn't tie myself to one brand of vehicle (which I agree with).

Does anyone have any experience with the Bosch Power Max 30 amp charger? Can it be installed to a 90 amp circuit? Am I missing anything?

I have found the Bosch Power Max charger to have questionable longevity. They seem to have control issues that result in fault conditions, rendering the station inoperable.

Since you're going with a Model 3, I would recommend installing a Tesla wall connector on a 60 amp breaker. This will allow you to charge the Model 3 at the full speed of 48 amps. If you're looking for something that will charge non-Teslas, you could go with a Clipper Creek HCS-60, although it is significantly more expensive than a Tesla wall connector.

If you're looking to future proof your charging needs, you could have your electrician pre-wire (or at least run conduit for) two more charging locations in your garage in a shared configuration. Depending on what the future brings, you can configure that rough-in for whatever setup you prefer at the time without having to worry about doing a retrofit installation. Clipper Creek also makes shared charging stations.

At the end of the day, how you configure your charging equipment depends on how much electricity you have available and what your actual needs are. Installing a sub panel in the garage just for vehicle charging might offer the most future flexibility at the lowest cost (unless you main panel is already in the garage).
 

BrokerDon

Active Member
Aug 23, 2014
1,399
1,291
Newport Coast, CA
I would go with a 100A breaker and the three circuits. Much less expensive to do now than add in the future. This means you probably need a 300A panel.

Have a reputable honest licensed electrician do a load calculation before you decide you need a larger main service panel (MSP) for your house. Our 3,300 sq. ft. single family home with 2 central AC units + 2 split AC units uses a 200A MSP. Our gen1 Tesla High Power Wall Charger is fed via a 100A breaker through a 100A sub-panel. This was from an electrical "Load Calculation" produced by our licensed electrician, approved by our building department, installed by our licensed electrician, and inspected by their electrical inspector.

However if you need more electrical circuit breaker spaces... and may add solar to your home now or in the future, you might want to consider a 225A "solar ready" MSP instead of a 200A "standard" (non "solar ready") MSP. It will cost a little more but definitely save a bunch of wiring and/or a MSP replacement if you ever decide to add solar... which unless your roof is completely shaded or facing completely north should be a "no brainer" to install in new construction.
 

ewoodrick

Well-Known Member
Apr 13, 2018
5,285
3,735
Buford, GA
I would not recommend a single breaker and put 3 chargers on it. I would recommend individual breakers for each.
A breaker is supposed to trip if there is an issue. It takes 100A+ to trip a 100A breaker. That means that it may be possible to arc-weld all of the cars together without tripping the breaker.
Also, this is probably going to mean that you want to get a bigger service panel, and may mean that the utility needs a larger transformer. If you are building a new house, just get it right to begin with.

I'd probably think about 3 60A circuits.
 
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rhino2627

Member
Mar 31, 2016
38
9
Elmhurst, IL
I would not recommend a single breaker and put 3 chargers on it. I would recommend individual breakers for each.
A breaker is supposed to trip if there is an issue. It takes 100A+ to trip a 100A breaker. That means that it may be possible to arc-weld all of the cars together without tripping the breaker.
Also, this is probably going to mean that you want to get a bigger service panel, and may mean that the utility needs a larger transformer. If you are building a new house, just get it right to begin with.

I'd probably think about 3 60A circuits.
From Tesla.com, "Up to four Tesla Wall Connectors can be linked together to intelligently share power from a single circuit breaker."

They recommend using a 100 amp breaker to maximize charging potential.
 
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rhino2627

Member
Mar 31, 2016
38
9
Elmhurst, IL
I would go with a 100A breaker and the three circuits. Much less expensive to do now than add in the future. This means you probably need a 300A panel. You can use the Tesla Wall Connector with an adapter for J1772 for other vehicles and their charger allows you to set maximum charge level for each connector individually. You need to set it higher than the max charge rate for the vehicle. The vehicle will never charge at a rate higher than its internal charger max rate. The cost for the Tesla Wall chargers is running around $400 on eBay for new ones. They (WCs) are excellent units. The Bosch chargers are over $800 for a 30A, a ridiculous price, you can get up to 80A with a Wall Connector.
I like the idea of installing multiple Tesla wall chargers, and using the J1772 adapter for a non-Tesla EV. Do you know if the automatic load management will work with Tesla and non-Tesla EVs charging at the same time?
 

Boourns

Active Member
Mar 9, 2016
1,577
1,984
Dallas
I was in the same position as you and went with a 125A sub-panel, which feeds a 14-50 outlet on one side of the garage and a 70A (or there about) line on the other. I use the 14-50 with the mobile connector now. The 72 is capped off, and later I'll install a wall connector or other EVSE when we become a no-ICE family. I'll be able to charge two cars at the same time in whatever apportionment of 100A is best for the circumstances. I found this to be the best balance of future-proofing for quick level 2 charging and cost. I think the builder charged us like $1100 for the entire setup.
 
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edlin303

Member
Jan 29, 2018
103
110
San Diego
I would not recommend a single breaker and put 3 chargers on it. I would recommend individual breakers for each.
A breaker is supposed to trip if there is an issue. It takes 100A+ to trip a 100A breaker. That means that it may be possible to arc-weld all of the cars together without tripping the breaker.
Also, this is probably going to mean that you want to get a bigger service panel, and may mean that the utility needs a larger transformer. If you are building a new house, just get it right to begin with.

I'd probably think about 3 60A circuits.
I still would maintain this is a better use case for a sub panel than 3x60. With 3x60, each car is limited with what it can draw (relevant if they buy a car capable of >48A in the future). If you run 100A or 120A to a sub panel, then you can today run 100A to an HPWC, or two or three HPWC with their intelligent sharing set up. Then in the future if you need a J1772 you can add a 40, 50, 60A circuit off the sub and if need be decrease the max amperage setting on the HPWC to avoid blowing the circuit.

Because of all of the above, if saving money up-front is of value, I believe you could run 100A now to one or more HPWC, and then down the road convert that to a sub-panel and hang multiple chargers off it if you get a non-tesla and need J1772 that doesn't support power sharing.

I do agree sharing one circuit between 3 random EVSEs is almost certainly not to code and a bad idea. But the HPWCs are designed for exactly that, so I see no harm in doing it for a Tesla-only home. For anyone else, multiple circuits and/or a sub panel are key.

*I am not an electrician, so obviously run the scenarios by a pro if you think you find one that works for you.
 

Rocky_H

Well-Known Member
Feb 19, 2015
6,660
7,955
Boise, ID
Good advice here. I'll just add: any builder who suggests a 30A breaker for a 30A charge plug doesn't understand the very basics of electrical systems -- or code.
Not necessarily. Naming conventions are somewhat split across the board from other manufacturers' charging units about whether the number is referring to the circuit or the delivered current. So the "30A unit" may be one that is intended for a 30A circuit and only delivers 20A, or it could be one that goes on a 40A circuit and only delivers 30A. I've seen both. So none of this implies that he's going to do a bad install or use the wrong size breaker versus what the equipment requires.

Oh, and as to the original question, I would say run a big feed to a subpanel, so you can put in what you want now, with maybe a 50 or 60A to a Tesla wall connector, but then later add on a 30A circuit or something for a different J1772 station.
 

ewoodrick

Well-Known Member
Apr 13, 2018
5,285
3,735
Buford, GA
From Tesla.com, "Up to four Tesla Wall Connectors can be linked together to intelligently share power from a single circuit breaker."

They recommend using a 100 amp breaker to maximize charging potential.
Paraphrased from original message "I agree that I may want to plan to charge multiple makes"

Just because the HPWC can do it, doesn't mean it is the best answer. If I was building a new house, I'd definitely want to make sure that I've got flexibility for the next 50 years. And in my old age, I may just decide to drive a Tesla Semi!
I'd go for some capacity and not limit myself to what the HPWC can do.
 

barjohn

Member
Sep 23, 2017
547
668
Riverside, CA
I charge a Bolt and a Tesla from two HPWCs on a 60A breaker. I would have done more but I don't have the spare capacity in my 200A service to do a 100A or I would have. Future cars may have much higher charging needs, think 400 mile range batteries or even greater. Don't be limited by your service and have to go to the expense of upgrading your service to your house. That can cost you many thousands of dollars, especially if you have underground service. You are responsible to replace the cables to meet the power requirements and that is really expensive after the fact and not too much more if done during construction.
 
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