Show your Lightning's home charging setup!

My Lightning is on the way and I finally got my second EnelX Juice Box installed in my garage. I'm using a software feature that allows both boxes to intelligently load share a single 50 amp circuit. If only car is plugged in, it will deliver a full 40 amps to the in-use box. If both are plugged in and charging, it will provide 20 amps to each box and will shift the amps over to the other vehicle once the first one has completed charging. It's a great option for those that have two EVs and aren't able to add another branch off of the main panel.

I've been using a JuiceBox since 2019 and it's been rock-solid. Customer service has also been great--I put in a request to add the Lightning to the vehicle database and they updated the software within 5 days. The android app and desktop portal work well and has many options for monitoring and smart home integration built in.

Not a great picture, and I’ve cleaned this up cosmetically since I took the picture last year

Technically, two EVSEs on one branch circuit is a code violation. But there’s nothing unsafe about it when they do load-sharing. I hope the code is changed to address this in the future.

Maquis said:

Technically, two EVSEs on one branch circuit is a code violation. But there’s nothing unsafe about it when they do load-sharing. I hope the code is changed to address this in the future.

Click to expand...

It looks like the code allows for this (with a subpanel off of a feeder circuit), but it's probably going to be hard to find an electrician and inspector that will recognize it: "Where an automatic load management system is used, the maximum equipment load on a service and feeder shall be the maximum load permitted by the automatic load management system."

There's going to be many 2-EV households coming online in the coming years and the industry is going to have to accommodate load sharing setups. It's not going to be possible for most people to add two 50 amp branches off of their panel and TBH most multiple EV households can get by sharing 50 amps (effectively 40 amps). It's much more convenient to have two separate taps that can be plugged in simultaneously--otherwise you have to remember to switch plugs overnight.

An alternative would be an EVSE with two taps. I don't think there are any that are smart or app-equipped at the moment.

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From the JuiceBox website:

For your electrician:
Code for Load sharing (NEC 2017)

625.42 Electric Vehicle Supply Equipment Circuit Rating

Former 625.14 has been revised and relocated to 625.41 as a result of Article 625 being reorganized. A new last sentence that includes provisions for an automatic load management system has been added to 625.41. The maximum electric vehicle supply equipment load on a service and feeder shall be the maximum load permitted by the automatic load management system. This revision provides relief from service upgrades in some cases, but an automatic load management system has to limit the load on the service to its capacity.



Code for Load sharing (NEC 2020)

625.42 Rating. The power transfer equipment shall have sufficient rating to supply the load served. Electric vehicle charging loads shall be considered to be continuous loads for the purposes of this article. Service and feeder shall be sized in accordance with the product ratings. Where an automatic load management system is used, the maximum equipment load on a service and feeder shall be the maximum load permitted by the automatic load management system.
Adjustable settings shall be permitted on fixed-in-place equipment only. If adjustments have an impact on the rating label, those changes shall be in accordance with manufacturer’s instructions, and the adjusted rating shall appear with sufficient durability to withstand the environment involved on the rating label. Electric vehicle supply equipment with restricted access to an ampere adjusting means shall be permitted to have ampere ratings that are equal to the adjusted current setting. Sizing the service and feeder to match the adjusting means shall be permitted. Restricted access shall prevent the user from gaining access to the adjusting means. Restricted access shall be accomplished by at least one of the following:

(1) A cover or door that requires the use of a tool to open
(2) Locked doors accessible only to qualified personnel
(3) Password protected commissioning software accessible only to qualified personnel

Here's my CSP.



Hmm, something is wrong here...

vandy1981 said:

It looks like the code allows for this, but it's probably going to be hard to find an electrician and inspector that will recognize it: "Where an automatic load management system is used, the maximum equipment load on a service and feeder shall be the maximum load permitted by the automatic load management system."

There's going to be many 2-EV households coming online in the coming years and the industry is going to have to accommodate load sharing setups. It's not going to be possible for most people to add two 50 amp circuits to their panel and TBH most multiple EV households can get by sharing 50 amps (effectively 40 amps). It's much more convenient to have two separate taps that can be plugged in simultaneously--otherwise you have to remember to switch plugs overnight.

An alternative would be an EVSE with two taps. I don't think there are any that are smart or app-equipped at the moment.

================
From the JuiceBox website:

For your electrician:
Code for Load sharing (NEC 2017)

625.42 Electric Vehicle Supply Equipment Circuit Rating

Former 625.14 has been revised and relocated to 625.41 as a result of Article 625 being reorganized. A new last sentence that includes provisions for an automatic load management system has been added to 625.41. The maximum electric vehicle supply equipment load on a service and feeder shall be the maximum load permitted by the automatic load management system. This revision provides relief from service upgrades in some cases, but an automatic load management system has to limit the load on the service to its capacity.



Code for Load sharing (NEC 2020)

625.42 Rating. The power transfer equipment shall have sufficient rating to supply the load served. Electric vehicle charging loads shall be considered to be continuous loads for the purposes of this article. Service and feeder shall be sized in accordance with the product ratings. Where an automatic load management system is used, the maximum equipment load on a service and feeder shall be the maximum load permitted by the automatic load management system.
Adjustable settings shall be permitted on fixed-in-place equipment only. If adjustments have an impact on the rating label, those changes shall be in accordance with manufacturer’s instructions, and the adjusted rating shall appear with sufficient durability to withstand the environment involved on the rating label. Electric vehicle supply equipment with restricted access to an ampere adjusting means shall be permitted to have ampere ratings that are equal to the adjusted current setting. Sizing the service and feeder to match the adjusting means shall be permitted. Restricted access shall prevent the user from gaining access to the adjusting means. Restricted access shall be accomplished by at least one of the following:

(1) A cover or door that requires the use of a tool to open
(2) Locked doors accessible only to qualified personnel
(3) Password protected commissioning software accessible only to qualified personnel

Click to expand...

Note that it says “service and feeder”, not branch circuit.

In other words, you could feed a 60A sub panel in your garage and run two 50A branch circuits from it, even though the combined load would exceed the 60A rating of the feeder.

Maquis said:

Note that it says “service and feeder”, not branch circuit.

In other words, you could feed a 60A sub panel in your garage and run two 50A branch circuits from it, even though the combined load would exceed the 60A rating of the feeder.

Click to expand...

Yes, always consult your electrician but you would need to have a subpanel off of a feeder circuit in order to have this install. That said, the JuiceBox has a failsafe that limits charging to 6 amps if the server connection is lost.

Maquis said:

Note that it says “service and feeder”, not branch circuit.

In other words, you could feed a 60A sub panel in your garage and run two 50A branch circuits from it, even though the combined load would exceed the 60A rating of the feeder.

Click to expand...

Agree. Also, the inspector has to accept the automatic load management "system". They may want to see a listing as such. Helps if the installation instructions include description of the feature as install instructions are part of equipment listing. That said, a March electrical inspector publication teaches inspectors of a need for a seperate UL916 energy management listing to be counted as such a sytem. We are still at a "good luck with your inspector" stage with this provision IMO.

The INTENT of the code is to ensure that safe installations exist. Most AHJ's (authorities having jurisdiction, represented by the inspector) are pretty reasonable if you can show them that the equipment is listed/tested, designed to do load balancing, and will not draw more than intended in most common situations unless there is an express "no no" written in code. After all, it's protected by upstream OCPD devices and as long as the conductors have been managed properly, it doesn't pose a risk nor violate general load rules.

However, occasionally you'll run into the "Barney with a Badge" AHJ who goes off the deep end with interpretations. "It doesn't say you can have a green receptacle, therefore you cannot have a green receptacle here! FAILED!" I typically recommend escalating such cases to a more senior/reasonable inspector, but occasionally you won't find one and will have to live with whatever they want (or file a lawsuit against the county/municipality, which never tends to go well.)

FlasherZ said:

The INTENT of the code is to ensure that safe installations exist. Most AHJ's (authorities having jurisdiction, represented by the inspector) are pretty reasonable if you can show them that the equipment is listed/tested, designed to do load balancing, and will not draw more than intended in most common situations unless there is an express "no no" written in code. After all, it's protected by upstream OCPD devices and as long as the conductors have been managed properly, it doesn't pose a risk nor violate general load rules.

However, occasionally you'll run into the "Barney with a Badge" AHJ who goes off the deep end with interpretations. "It doesn't say you can have a green receptacle, therefore you cannot have a green receptacle here! FAILED!" I typically recommend escalating such cases to a more senior/reasonable inspector, but occasionally you won't find one and will have to live with whatever they want (or file a lawsuit against the county/municipality, which never tends to go well.)

Click to expand...

That’s all well and good, but 625.40 specifically requires an “individual branch circuit” and “Each circuit shall have no other outlets.” There are no exceptions for load-sharing, and no inspector should pass an installation if this is violated.

I do agree with you in that since the NEC is a restrictive code (as opposed to permissive) any inspector who fails an installation because “the code doesn’t say you can do it” needs to find another job.

Looks like you’re all set !

I know nothing about electrical,
And am still trying to figure out if I might have 80 amp coming to my garage by chance.

I found this junction box in the garage that appears to be there to feed the baseboard electric heat on the other side of the wall.

anyone know what baseboard heat needs for amps ?

I have 200 panel, so I think I’m set there.
I just need to get enough electrical into the garage, which is separated from the main house where the panel is, with a slab concrete addition put on in the 80’s.

maybe this junction box means they laid a pipe under the slab to feed in wiring, which maybe I can snake through that same pipe to get the needed wiring to the Charge Station Pro ?

sorry if these are all dumb questions. I clearly know nothing

My design sketch:




Cycling for 10 hours, I'll get a solid 5 miles of range.

FlasherZ said:

The INTENT of the code is to ensure that safe installations exist. Most AHJ's (authorities having jurisdiction, represented by the inspector) are pretty reasonable if you can show them that the equipment is listed/tested, designed to do load balancing, and will not draw more than intended in most common situations unless there is an express "no no" written in code. After all, it's protected by upstream OCPD devices and as long as the conductors have been managed properly, it doesn't pose a risk nor violate general load rules.

However, occasionally you'll run into the "Barney with a Badge" AHJ who goes off the deep end with interpretations. "It doesn't say you can have a green receptacle, therefore you cannot have a green receptacle here! FAILED!" I typically recommend escalating such cases to a more senior/reasonable inspector, but occasionally you won't find one and will have to live with whatever they want (or file a lawsuit against the county/municipality, which never tends to go well.)

Click to expand...

It's not only that though. There is a common theme throughout the code of protecting from adjustments that unqualified users can make and cause a system to be overloaded. A lot more history with how to treat breakers whose trip values can be adjusted than with these "automatic load management systems".

Here is the setup we currently have. Already has wiring for 100A run from our panel. Plan is to swap the disconnect for a sub panel and add the FCSP set at 40A in parallel with the existing EVSE so the wife and I can charge at the same time.

I installed this about a month ago. Waiting on my Lightning to arrive. It's blend date was 6/1, still waiting on the modules to pop and tracker to update.

In the meanwhile my wife's friend with a Model 3 Tesla visited the other day so I tested the Charge Point on it and made sure it worked.

60 Amps to the sub-panel with a 50 amp breaker to the 14-50 outlet and a 60 amp breaker to the Charge Point.