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Load-sharing home setup

astonius

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I need some guidance on my home setup. We have 200A service, over half of which is dedicated to HVAC. The garage has a sub-panel we are looking to tap into to charge two EVs (an R1T and a Model X). An electrician came out and said he could add two circuits, one 60A and one 50A, both wired with #6, and give us two NEMA 14-50s that could be converted to work with wall connectors if we wanted. This sounded great, but then I remembered the sub-panel feeds into a 90A breaker in the main panel, so if both cars tried to pull at peak we'd be exceeding the load limit on the sub-panel. I asked him about this, and he said yes, we could potentially cause issues if we're using the oven, the dryer, and charging both cars at the same time.

I then proposed just going to a single 60A circuit and setting up a load-sharing system but with two 14-50 receptacles (for flexibility) on the same circuit. He said that it is not legal to put multiple 14-50 receptacles on the same circuit. Am I missing something, or is this just a NEMA limitation? If instead of doing NEMA 14-50s we just wired directly into two load-sharing EVSE connectors would that be allowed on the same 60A circuit without a sub-panel? I fully admit I'm a complete newbie when it comes to this stuff, just want to get the best possible charging setup for 2 EVs that I can at the most efficient price and without overloading my system or breaking code.
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crashmtb

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Hardwire a charger that does load sharing, and can be ā€œdaisy chainedā€œ with a second. Thatā€™s one circuit, and you donā€™t have to deal with the compromises of a plug.

if the concern is taking it with youā€¦itā€™s not like itā€™s cemented in place. Remove charger, disable and cap off that circuit. Job done.
 
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astonius

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Hardwire a charger that does load sharing, and can be ā€œdaisy chainedā€œ with a second. Thatā€™s one circuit, and you donā€™t have to deal with the compromises of a plug.

if the concern is taking it with youā€¦itā€™s not like itā€™s cemented in place. Remove charger, disable and cap off that circuit. Job done.
That's exactly what I'm envisioning, just wasn't sure that would work and wanted to possibly backfill with NEMA plugs if we moved out, but I guess we could just cap it and let the new owners do whatever they want. Thanks for the advice!
 

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That's exactly what I'm envisioning, just wasn't sure that would work and wanted to possibly backfill with NEMA plugs if we moved out, but I guess we could just cap it and let the new owners do whatever they want. Thanks for the advice!
Or just leave them installed, that will be a great selling feature to have your listing stand out if you do decide to sell.
 

crashmtb

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That's exactly what I'm envisioning, just wasn't sure that would work and wanted to possibly backfill with NEMA plugs if we moved out, but I guess we could just cap it and let the new owners do whatever they want. Thanks for the advice!
in the case of moving, and not leaving the charger behind, you could also just stick a plug where the charger was. (But the breaker might have to be changed too).

Seems better to start off hardwired anyway. Or hardwire one and put one on a plug.
 

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astonius

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Or just leave them installed, that will be a great selling feature to have your listing stand out if you do decide to sell.
I considered that, but I don't know that it would be a big selling point where I live. Not a ton of EV adoption yet. Guess it all depends on when we sell and the state of the EV and EVSE markets at that time. At the very least it'd be wired and ready to go for the new buyer, they'd just have to BYOB.
 
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astonius

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in the case of moving, and not leaving the charger behind, you could also just stick a plug where the charger was. (But the breaker might have to be changed too).

Seems better to start off hardwired anyway. Or hardwire one and put one on a plug.
I think the concern here is that I can only have one receptacle per circuit, so the daisy-chained setup wouldn't work with a plug in the mix (at least that's my understanding of what the electrician is saying).
 

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I then proposed just going to a single 60A circuit and setting up a load-sharing system but with two 14-50 receptacles (for flexibility) on the same circuit. He said that it is not legal to put multiple 14-50 receptacles on the same circuit. Am I missing something, or is this just a NEMA limitation? If instead of doing NEMA 14-50s we just wired directly into two load-sharing EVSE connectors would that be allowed on the same 60A circuit without a sub-panel? I fully admit I'm a complete newbie when it comes to this stuff, just want to get the best possible charging setup for 2 EVs that I can at the most efficient price and without overloading my system or breaking code.
The 2020 code made it quite explicit:

625.40 Electric Vehicle Branch Circuit. Each outlet installed for the purpose of charging electric vehicles shall be supplied by an individual branch circuit. Each circuit shall have no other outlets.
Older versions left some ambiguity and the manufacturer's ran with it (the Juicebox manual claims a 2017 code section that supports having multiple receptacles in a listed load sharing config -- I read that section and don't think it actually says that).

I hardwired my units to get the 48A capacity and installed two on a single 60A breaker for load sharing.

Even hardwire, you can cap the wires and plug the holes if you really want to take them with you. But a well-built charging solution is just going to become more and more desirable in the coming years. I'd just leave them behind.
 

crashmtb

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I think the concern here is that I can only have one receptacle per circuit, so the daisy-chained setup wouldn't work with a plug in the mix (at least that's my understanding of what the electrician is saying).
Ahh. So the only feasible option then is to hard wire them
 
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astonius

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Thanks @timesinks for the link! Really nice setup. So like @crashmtb was saying, the second Juicebox is daisy-chained to the first right? If so, two questions about that. If theoretically someone only wanted to use the secondary could you junction the run between the panel/primary and primary/secondary to make the secondary the new (and only) primary? Also is the primary always considered the first one in the series?
 

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Thanks @timesinks for the link! Really nice setup. So like @crashmtb was saying, the second Juicebox is daisy-chained to the first right? If so, two questions about that. If theoretically someone only wanted to use the secondary could you junction the run between the panel/primary and primary/secondary to make the secondary the new (and only) primary? Also is the primary always considered the first one in the series?
The only reason there is a primary is it defines who handles the communication. You can use either charger and if it is the only one being used it will pull itā€™s max load.
 

Cavalryscout18

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Thanks @timesinks for the link! Really nice setup. So like @crashmtb was saying, the second Juicebox is daisy-chained to the first right? If so, two questions about that. If theoretically someone only wanted to use the secondary could you junction the run between the panel/primary and primary/secondary to make the secondary the new (and only) primary? Also is the primary always considered the first one in the series?
There is an easier way to charge two cars at once with one NEMA 14-50 connection. The first option is to buy a Grizzl-E duo charger that connects to one NEMA 14-50 plug and can auto switch to charge one vehicle and then the other. Or it can charge both at once (half capacity to each). It costs $900 on Amazon. This would work better if you didnā€™t have a Tesla since you will need to use the J1772 adapter for your Tesla so you will lose some functionality with charging your Tesla. Since I have a Model 3, I wanted to find a way to keep using my Tesla charger and not lose that functionality so I found a NEMA splitter called the NeoCharger. It cost about $500 on Amazon and it allows you to split one NEMA 14-50 plug so you can connect two NEMA 14-50 chargers and it can auto switch between the two to ensure only one vehicle charges at once. So now I can plug in my Tesla charger on one plug and the Rivian Charger on the other and it will auto switch between the two at night as both are plugged in. Then I wonā€™t lose the functionality of any vehicle charger. And I only need one NEMA plug. The only limit is that both of these options cap at 40 amps so if you wanted to charge faster, that wonā€™t work for these options. Itā€™s enough for me, though. The Model 3 is capped at 32 amps of charging and 40 amps of charging the Rivian will lead to 20 miles per hour, which is plenty for me.
 
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astonius

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There is an easier way to charge two cars at once with one NEMA 14-50 connection. The first option is to buy a Grizzl-E duo charger that connects to one NEMA 14-50 plug and can auto switch to charge one vehicle and then the other. Or it can charge both at once (half capacity to each). It costs $900 on Amazon. This would work better if you didnā€™t have a Tesla since you will need to use the J1772 adapter for your Tesla so you will lose some functionality with charging your Tesla. Since I have a Model 3, I wanted to find a way to keep using my Tesla charger and not lose that functionality so I found a NEMA splitter called the NeoCharger. It cost about $500 on Amazon and it allows you to split one NEMA 14-50 plug so you can connect two NEMA 14-50 chargers and it can auto switch between the two to ensure only one vehicle charges at once. So now I can plug in my Tesla charger on one plug and the Rivian Charger on the other and it will auto switch between the two at night as both are plugged in. Then I wonā€™t lose the functionality of any vehicle charger. And I only need one NEMA plug. The only limit is that both of these options cap at 40 amps so if you wanted to charge faster, that wonā€™t work for these options. Itā€™s enough for me, though. The Model 3 is capped at 32 amps of charging and 40 amps of charging the Rivian will lead to 20 miles per hour, which is plenty for me.
I appreciate the recommendation. Considering the price and extra 8A I'll probably just go hardwired. Any idea if the Tesla Gen 3 wall connector a good load-sharing option? I know I'd need a Tesla to J1772 adapter for the R1T, but it surprisingly seems like the most affordable route for load-sharing, and they are in stock.
 

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Iā€™d take two circuits but thatā€™s just me. With #6 you canā€™t technically pull more than 50a anyways so why not have two chargers set to to 35-40a? Might avoid a situation where you have to argue about who has less charge and needs the plug more.
 

Rousie13

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We have two 40A Wallbox units load sharing a 50A circuit. 40A really is adequate unless both vehicles are being driven a lot everyday. We have had no problems with this setup in keeping our vehicles adequately charged.
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