Juice Box 40 and NEMA 14-50 outlet on the same line

[RickMachE]

Thanks all for the comments! I was using the mobile charging kit as a 'proof of concept' for any times I potentially may need to charge inside the garage vice outside.

If/when we get a second EV, I'll get a second Juice Box 40 and set them up as a pair, and upgrade wiring if necessary.

First, if the circuit was wired properly for the JuiceBox hardwired charger, there should be no GFCI breaker.

Second, if the circuit was wired properly for the 40amp charger, an IDENTICAL JB40 will share the load, and no wiring changes, or breaker changes, are needed.

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[Maquis]

First, if the circuit was wired properly for the JuiceBox hardwired charger, there should be no GFCI breaker.

Second, if the circuit was wired properly for the 40amp charger, an IDENTICAL JB40 will share the load, and no wiring changes, or breaker changes, are needed.

EVSE load sharing as permitted by code is very misunderstood. Even with load sharing, each EVSE requires a dedicated branch circuit.
Where load sharing comes into play is when sizing feeders and calculating service load.
In this case, he could have a 50 or 60A feeder run to a small subpanel in the garage and run a 50A branch circuit to each load-shared EVSE from the subpanel. Load share setting must be set to not exceed 80% of the feeder rating.

 

[RickMachE]

EVSE load sharing as permitted by code is very misunderstood. Even with load sharing, each EVSE requires a dedicated branch circuit.
Where load sharing comes into play is when sizing feeders and calculating service load.
In this case, he could have a 50 or 60A feeder run to a small subpanel in the garage and run a 50A branch circuit to each load-shared EVSE from the subpanel. Load share setting must be set to not exceed 80% of the feeder rating.

I am not an electrician, nor do I play one on TV, and I don't stay in Holiday Inn Express hotels.

Here's what JuiceBox says:

What is Load Sharing?

You just installed and added your second of two JuiceNet enabled devices, but only have one electrical circuit. Good news, the JuiceNet servers allow you to share one electrical circuit safely while charging both vehicles.

https://support-emobility.enelx.com/hc/en-us/articles/360002651411-What-is-Load-Sharing-

 

[Maquis]

I am not an electrician, nor do I play one on TV, and I don't stay in Holiday Inn Express hotels.

Here's what JuiceBox says:

What is Load Sharing?

You just installed and added your second of two JuiceNet enabled devices, but only have one electrical circuit. Good news, the JuiceNet servers allow you to share one electrical circuit safely while charging both vehicles.

https://support-emobility.enelx.com/hc/en-us/articles/360002651411-What-is-Load-Sharing-

Their incentive is to sell hardware, not insist on code compliance when it might impede those sales.
Here’s what the code says:

Installing 2 EVSEs on a single branch circuit is a clear violation of 625.40. 625.42 allows load sharing to be considered for feeders and services only, not branch circuits.
Also keep in mind the NEC definition of “outlet”. “Point where utilization equipment connects to premesis wiring.” Outlet does not just mean receptacle.

 

[RickMachE]

Did you read what they have posted at that link?

 

[JeffGo]

Against code as pointed out.

I use the Ford mobile charger only with a NEMA 14-50 outlet, and yes, "stacked" GFCI can be a nuisance. About 10-20% of the time, I will see either the Ford charger's amber light (usually internal GFCI tripped but could be other fault) or the GFCI breaker tripped (code requirement in my state), so I have to reset that.

 

[Maquis]

Did you read what they have posted at that link?

Yes - they quote the same NEC articles that I did.

 

[RickMachE]

Yes - they quote the same NEC articles that I did.

So their interpretation and yours differ, correct?

If we get a 2nd vehicle, my plan is to get another JB48 and setup load sharing. But no plans for a 2nd one at this point.

 

[Maquis]

Against code as pointed out.

I use the Ford mobile charger only with a NEMA 14-50 outlet, and yes, "stacked" GFCI can be a nuisance. About 10-20% of the time, I will see either the Ford charger's amber light (usually internal GFCI tripped but could be other fault) or the GFCI breaker tripped (code requirement in my state), so I have to reset that.

Amber is always the overtemp indicator, not ground fault.

 

[Maquis]

So their interpretation and yours differ, correct?

If we get a 2nd vehicle, my plan is to get another JB48 and setup load sharing. But no plans for a 2nd one at this point.

I don’t think so. This is their interpretation:

Still only says “service and feeder.” I didn’t see anywhere where they state that its permissible to install 2 EVSEs on a single branch circuit. But they also don’t spell out specifically that you can’t. They simply choose to ignore 625.40.

 

[daemonic3]

My interpretation is "outlet" would be a receptacle and not hard wired. Hard wired restricts what is present for the load management system to ensure it enforces the limit.

What my electrician(s) told me while getting quotes, is that if ANY receptacle (nema 14-50) is present then ANY device can be plugged in there and you have to assume if there are 2 receptacles that 2 things might get plugged. No matter how smart I am at moving my EVSE to one outlet at a time, any moron or future homeowner could plug in a welder, RV, heater, etc and trip. So based on that spirit, that is my interpretation of "outlet". I believe 2 hard-wireds with load management would be allowed because there is nowhere for the lowest common denominator human to plug something in.

What I had my electrician do was install my one Nema 14-50 receptacle, but add a spare junction box with a 12" slack loop as a tap point if I want to move my receptacle in the future. Or I may install a 2nd receptacle and add a 3-pole knife switch at the j-box to only activate one receptacle at a time. I don't know what our car situation may be years down the road and wanted backup plans.

Anyway, very interested to know what 625.40 real definition of "outlet" is here.

 

[Mach-Lee]

Their incentive is to sell hardware, not insist on code compliance when it might impede those sales.
Here’s what the code says:

Installing 2 EVSEs on a single branch circuit is a clear violation of 625.40. 625.42 allows load sharing to be considered for feeders and services only, not branch circuits.
Also keep in mind the NEC definition of “outlet”. “Point where utilization equipment connects to premesis wiring.” Outlet does not just mean receptacle.

This has been fixed in the 2023 NEC so you can share a branch circuit with multiple EVSEs with a load management system. It was an accidental omission in the 2020 version. Obviously there is no point in discussing a load management system unless it was permitted.

 

[Maquis]

This has been fixed in the 2023 NEC so you can share a branch circuit with multiple EVSEs with a load management system. It was an accidental omission in the 2020 version. Obviously there is no point in discussing a load management system unless it was permitted.

Nice! Seems like an obvious fix as there is no technical reason not to allow it. I haven’t started digging into the 23 NEC yet.
The only issue is that some jurisdictions are notoriously slow to adopt new codes. My location is still on the 2008 NEC! Some inspectors will go along with things like this even if not adopted yet. As always, YMMV.

 

[JeffGo]

Amber is always the overtemp indicator, not ground fault.

Not really. Amber is generic for a fault that can probably be recovered. It may be heat related ("IF").

 

[khbkhb]

[QUOTE="mateo, post: 509832, member: 13654"

Likely the GFCI isn't compatible with the Ford Mobile Charger.
[/QUOTE]

People often have problems with multiple GFCI's in series, especially with large inrush current. While code compliant, it is generally considered poor practice to have GFCI in series ... and you can't remove the one inside the mobile charger.

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