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It is perfectly acceptable to plug in a device that draws less than the maximum load the breaker can handle. Look around and tell me how many devices in the room you are in draw the full 15A of the breaker on the circuit they are plugged in to. Think your cell phone charger draws 15A @ 120V? Your computer? TV? Lamp?

The key is the breaker needs to be sized to protect the wire in the circuit. The relevant parts of your statement are in bold.

As far as multiple outlets for EVSE's on a single 240V circuit, how many 15A rated outlets are on a typical 120V 15A circuit? More than one?
If you plug more devices in than the circuit will support, the breaker will trip. Try running 2 hair dryers in the same bathroom.

2 properly configured EVSE's on the same circuit will not exceed it's capacity and be no problem. Improperly configured, they will trip the breaker on a properly designed circuit.
It is certainly acceptable to plug a device that draws 2A into a 15A receptacle.

It is not proper to install a 50A receptacle on a 60A circuit (60A breaker protected) or a 15A receptacle on a 50A circuit.

We don't have to even discuss why, just refer to the NEC.

The breaker protects the entire circuit, not just the wiring. The circuit includes the receptacle. You wire a 30A receptacle into a 50A circuit with appropriate wire for 50A and a 50A breaker and you are in violation of code. You could draw 50A through that receptacle and cause it to overheat without the breaker opening the circuit.

He can hardwire his two JuiceBox units to his 60A circuit but he can't install two (or even one) 50A receptacles to plug them in.

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210.21(B)(3) Receptacle Ratings. Where connected to a branch circuit supplying two or more receptacles or outlets, receptacle ratings shall conform to the values listed in Table 210.21(B)(3), or, where rated higher than 50 amperes, the receptacle rating shall not be less than the branch-circuit rating.

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The table says you can use a receptacle rated not over 15A on a 15A circuit, 15 or 20A on a 20A, 30A on a 30A, 40 or 50A on a 50A and from the above language, any circuit greater than 50A requires a receptacle >= to the circuit rating so 50A receptacles are not permitted on a 60A circuit
 

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I understand the NEC doesn't preclude multiple outlets on a 50A circuit. So the 60A breaker could be replaced by a 50A and the circuit could have two 50A receptacles. It is then up to the user to ensure the combined continuous load does not exceed 40A [80% of 50].

Please correct me if this is wrong.
 

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Probably the least expensive route is to have the wiring that is going to a box with one receptacle now, turned into a junction box by removing the receptacle and running two sets of cables to two new boxes, each with a 14-50R receptacle. If your receptacle box is large enough to allow for two 14-50R receptacles and all of that heavy #6 wire to be joined then you could in theory put two receptacles in one box. Boxes are cheap so I wouldn't try and stuff 3 sets of #6 -3 wire into a box with a receptacle. If you use #6 -4 you definitely would not want to try it. To meet electrical code you should be using #6 -4 even though most EVSE's don't use the neutral wire on a 14-50R receptacle, any one with an RV plugging into the receptacle thinking it will work would fry their electrical equipment.
Thanks. That makes sense. Perhaps I'll wait until EV #2 shows up and go the route you are suggesting.
 

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I understand the NEC doesn't preclude multiple outlets on a 50A circuit. So the 60A breaker could be replaced by a 50A and the circuit could have two 50A receptacles. It is then up to the user to ensure the combined continuous load does not exceed 40A [80% of 50].

Please correct me if this is wrong.
I believe that is correct.
 

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He can hardwire his two JuiceBox units to his 60A circuit but he can't install two (or even one) 50A receptacles to plug them in.

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210.21(B)(3) Receptacle Ratings. Where connected to a branch circuit supplying two or more receptacles or outlets, receptacle ratings shall conform to the values listed in Table 210.21(B)(3), or, where rated higher than 50 amperes, the receptacle rating shall not be less than the branch-circuit rating.

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The table says you can use a receptacle rated not over 15A on a 15A circuit, 15 or 20A on a 20A, 30A on a 30A, 40 or 50A on a 50A and from the above language, any circuit greater than 50A requires a receptacle >= to the circuit rating so 50A receptacles are not permitted on a 60A circuit
This is true, but my objection to your example was using 15A wire on a 30A circuit. No Beuno even if you only have a 15A load.

Once you exceed 50A on a circuit, there are a number of things that change. The requirement for a readily accessible disconnect that can be locked in the open position (this is in addition to the breaker for the circuit) comes to mind.


I understand the NEC doesn't preclude multiple outlets on a 50A circuit. So the 60A breaker could be replaced by a 50A and the circuit could have two 50A receptacles. It is then up to the user to ensure the combined continuous load does not exceed 40A [80% of 50].

Please correct me if this is wrong.
An inspector might have a problem with 625.17
210.17 Electric Vehicle Branch Circuit. Outlet(s) installed
for the purpose of charging electric vehicles shall be
supplied by a separate branch circuit. This circuit shall
have no other outlets.

This was added in the 2014(?) revision. The NEC often lags behind technology, and down the road we will likely see more changes to article 625 that deals specifically with EV charging. It may or may not allow devices that share a load to be installed in multiple locations/outlets.

The NEC can be interpreted as contradicting itself in many instances, and individual inspectors will often read different things into the same section. YMMV

This could be interpreted as the branch circuit for EV charging can have multiple outlets for EVSE's but no other outlets. Or it could be read to mean that each outlet must be on a separate circuit.

The best way to install multiple EVSE's is to hardwire them. That way you only need to convince your inspector that they will indeed work together and never draw more than the circuit is rated to protect. They (and I) might have a problem with them "forgetting" that another unit is installed on the same circuit. We've all had to reboot devices (computers, cell phones, Bolt EV display screen, etc) to get them functioning correctly. Anyone know what the "fallback" draw is on a unit that loses communication with another EVSE that it is load sharing with? 50%? Or 25% if the EVSE allows up to 4 units to load share?
 

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Gary, thanks for the lead.

It appears NEC 210.17 was moved to 625.40 in 2017 and reads: "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." This, in my mind, removes the ambiguity in 210.17 that referenced "outlet(s)".

Based on this, I think that my previous statement that 2 50A outlets could be installed on one 50A circuit for the purposes of EV charging is against NEC. To have multiple plug-in EVSEs, their outlets need to be on difference circuits. Multiple EVSEs can be hardwired on one circuit however and, as Gary mentioned, "you only need to convince your inspector that they will indeed work together and never draw more than the circuit is rated to protect." To my knowledge the only units that have this advertised functionality are the Clipper Creek Share2 units and the Tesla Wall Connector but I haven't seen any documentation that says what happens if they lose communication between units.
 

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This is true, but my objection to your example was using 15A wire on a 30A circuit. No Beuno even if you only have a 15A load.
I don't believe I said it was OK to use wire rated for 15A on a 30A circuit (presumably meaning a 30A breaker). But I perhaps misunderstood a point you were making.

I do think we are now all in agreement on the basic issue that was posed, that putting 50A receptacles on a circuit protected by a 60A breaker doesn't meet code and he should get another licensed electrician to verify and fix as required.
 

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I love a good technical debate. Thanks for the read. I would add that there is a lot of good advice in here, and some bad advice too. Understand that codes vary from region to region they aren't completely and absolutely correct, though required for passing your local inspection. In general, EVSE installations are special use, and may fall under different rules. Do EVSEs need to be mechanically connected to be considered one EVSE (one box with two J1772s) or is software connection considered sufficient (though 2 separate units, they behave identically to the unit with one base and two plugs).

In general, (even though code may require in your region) I don't feel like there is any safety concern specifically with using a 30A receptacle on a 40 amp circuit, but something that should be confirmed - there should be internal fusing on the appliance/equipment such that if there was an over draw, but not enough to trip the breaker, the internal fuse would blow, before damaging the equipment or wiring.

Many receptacles purposefully allow for equipment with lesser ratings to be plugged into those circuits - a 20A receptacle has a T slot to allow for 20A or 15A appliances... probably a lot of these don't have internal fusing either.

I didn't make the rules, I just try to understand them.
 

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So, I finally got a different electrician to come out and take a look. I referenced all the NEC code you guys have mentioned. So turns out I am in NYC and therefore NEC code does not apply here. He states NEC is adoptable standard, but authorities may choose not to adopt it and have their own code. NYC chose that approach. It took the NEC 2008 code and then modified it to fit the city's needs, and that is what is in effect. All the outlets are following that code apparently.

That being said, turned out that is a moot point since I misunderstood what my previous electrician had told me. Both my Juiceboxes are on an outlet and they both have independent connections to the panel that is protected with 50A breakers. It's just that the wire from the rear EVSE goes into the JBox that provides the wire for the front EVSE and they go into the building from there. I assumed incorrectly that it was branched there. The panel itself however only has a 60A breaker and the wiring from the meter will not allow a higher amperage breaker to be installed. So that's why I was told to keep the combined load below 50A. Technically it's supposed to be 48A but I guess the guy was just rounding it up to make it easier.

So in the end, thankfully second electrician confirmed that the electrical system meets NYC Electrical code. I want to thank all of you that were concerned enough to point out the potential danger.
 

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Good clarification p56

Many places do NYC does, they adopt a particular revision of the NEC and then make a few modifications

If I'm reading what you wrote, it seems you have a subpanel that is fed from your service panel with a 60A breaker (in the service panel). That subpanel has two 50A breakers that feed the two JuiceBox EVSEs and while each individual JuiceBox is limited to 40A (due to 50A breaker) they can combine for up to 48A (based on 60A breaker feeding the subpanel).

Sounds like a great setup, exactly twice the available power I use to charge my one Bolt with now so should work out well for two EVs even with pretty high usage.
 

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We have a Bolt and an Audi e-tron. I'm going with a 60A circuit and starting with a single Clipper Creek HCS unit., but it will have a COSMOS card installed. CC calls this "Share2 Circuit Sharing". If needed, I'll add a second HCS-60, and they'll share the circuit, providing 24A to each active charger, or up to 48A for one. As a reminder, the Bolt is maxed out at accepting 7.2 kW, and the e-Tron 9.6. This means that the Bolt (with its 60kwh battery)is maxxed out with an HCS-40 charging a dry battery in 8.5 hours, and the e-tron with its 95 kwh battery maxxing out with a HCS-50, in 10 hours. Going with a HCS-60 for futureproofing, and will add a second is needed. Each car does about 500 miles a month. I can go two weeks with the Bolt. The e-tron is brand new and wicked heavy, so I don't have a feel for it yet.

Yeah, it's a little pricey, but I'm OK with it. My power company doesn't seem to offer off-peak rates, and WiFi is there to be hacked. The Clipper Creek unit does not do WiFi. I also like the optional physical access key that enables you to turn off the control wires, so your empty driveway doesn't become a haven for poachers 20 minutes after you go to work in the morning.
 
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