Wall Connector Powersharing Question/Help

[brush1]

So I'm trying to figure out if this would work/ be to code so any electricians that can chime in would be of help.

My plan is to feed a 125amp sub panel from my main with a 60amp breaker/feeder. In the sub panel I'll install two 60 amp breakers and wire these to each gen 3 wall connector. I'll setup power sharing to pull no more than 48 amps between the two wall connectors at 1 time. Is this acceptable?

 

[jjrandorin]

Your existing thread with this question already exists here on TMC, here:

(Calling All Electricians) Two Charger Setup/ Subpanel/ Power Sharing

So I'm looking for some guidance on a new two wall connector install: My current setup is an old nema 14-50 plug, powered by a 60amp breaker from my main panel. My plan is to remove the nema plug, install a 125 amp sub panel (feeding it from the old nema plug), install two 60 amp breakers in...

teslamotorsclub.com

We dont normally allow cross posting the same thing, but in this specific case its likely you posted it here because you didnt get the information you were specifically looking for in the other thread. Thats why I didnt merge this back with that thread.

 

[brush1]

Your existing thread with this question already exists here on TMC, here:

(Calling All Electricians) Two Charger Setup/ Subpanel/ Power Sharing

So I'm looking for some guidance on a new two wall connector install: My current setup is an old nema 14-50 plug, powered by a 60amp breaker from my main panel. My plan is to remove the nema plug, install a 125 amp sub panel (feeding it from the old nema plug), install two 60 amp breakers in...

teslamotorsclub.com

We dont normally allow cross posting the same thing, but in this specific case its likely you posted it here because you didnt get the information you were specifically looking for in the other thread. Thats why I didnt merge this back with that thread.

Thanks

 

[Sophias_dad]

So I'm trying to figure out if this would work/ be to code so any electricians that can chime in would be of help.

My plan is to feed a 125amp sub panel from my main with a 60amp breaker/feeder. In the sub panel I'll install two 60 amp breakers and wire these to each gen 3 wall connector. I'll setup power sharing to pull no more than 48 amps between the two wall connectors at 1 time. Is this acceptable?

That is fine. Make sure the feeder wire for the 60 amp panel is at least 4 gauge(that is 4 or lower number) NMB, or at least 6 gauge if you run individual conductors through conduit. Same goes for each of the circuits going to the HPWC's


TBH, I'd probably make it more like a 75amp panel or more if you have the capacity, so you can put a standard outlet or lighting or other circuit(s) on the subpanel as well.

 

[ATPMSD]

TBH, I'd probably make it more like a 75amp panel

If he goes with a higher amperage then I suggest 80 amps instead of 75 amps. They don’t make a 75 amp breaker and the same size wire is used for 80 amps anyway.

 

[brush1]

That is fine. Make sure the feeder wire for the 60 amp panel is at least 4 gauge(that is 4 or lower number) NMB, or at least 6 gauge if you run individual conductors through conduit. Same goes for each of the circuits going to the HPWC's


TBH, I'd probably make it more like a 75amp panel or more if you have the capacity, so you can put a standard outlet or lighting or other circuit(s) on the subpanel as well.

So I'm stuck with 6/3 nmb for the feeder wire from the main. This is a new production home build so I'm stuck with what is there. I'm trying to keep this as simple as possible and figured my above would be the easiest.

 

[brush1]

If he goes with a higher amperage then I suggest 80 amps instead of 75 amps. They don’t make a 75 amp breaker and the same size wire is used for 80 amps anyway.

I'm stuck with what the builder is putting in place 6/3 nmb. Any idea if my above setup would work?

 

[jjrandorin]

As I said in the other thread, I am no where near to being an electrician. With that out of the way, I dont think you can run 6 gauge NMB at 60amps. I think you can run 6 Gage THHN in conduit like that, but dont think you can run NMB like that.

I think your plan would work if you make everything 50 amps instead of 60amps.

@Sophias_dad or @Rocky_H Or @qdeathstar among others would be able to confirm, though, I freely admit most of what I know about these topics I learned here.

 

[brush1]

As I said in the other thread, I am no where near to being an electrician. With that out of the way, I dont think you can run 6 gauge NMB at 60amps. I think you can run 6 Gage THHN in conduit like that, but dont think you can run NMB like that.

I think your plan would work if you make everything 50 amps instead of 60amps.

@Sophias_dad or @Rocky_H Or @qdeathstar among others would be able to confirm, though, I freely admit most of what I know about these topics I learned here.

I'm not an electrician either and was hoping someone could shed some light. I've got a good grasp of what needs to be done, just working out the fine details. Thanks

 

[ATPMSD]

Also not an electrican but here is my understanding of what you can do.

6/3 nmb is rated at 55-amps, however, you can use a 60-amp breaker on a 6/3 nmb to feed the subpanel (allowed by code). For the Wall Connectors you must comply with the 80% rule, which means each Wall Connector must be set to a 50 amp circuit and you will use 50 amp breakers for each, use 6/2 for each as you do not need the neutral.

You will set load sharing to a 50 amp circuit. All breakers should be standard breakers, no GFICs.

 

[terranx]

You will set load sharing to a 50 amp circuit. All breakers should be standard breakers, no GFICs.

For what it's worth, the load sharing part you set the actual current draw (as in after the 80% rule is applied). And you can set that in 1 amp increments. So he can configure the powersharing to split 44 amps (80% of 55A) since that's what the wiring would actually support.

 

[ATPMSD]

So he can configure the powersharing to split 44 amps (80% of 55A) since that's what the wiring would actually support.

Cool! I did not know that. Would this then be a setting of 55 amps for the max sharing load limit?

 

[Sophias_dad]

For what it's worth, the load sharing part you set the actual current draw (as in after the 80% rule is applied). And you can set that in 1 amp increments. So he can configure the powersharing to split 44 amps (80% of 55A) since that's what the wiring would actually support.

I wonder if you could also cheat the system and say that loadsharing is enabled, but only have one participant, and still set the max current in 1 amp increments!

 

[qdeathstar]

Cool! I did not know that. Would this then be a setting of 55 amps for the max sharing load limit?

No 44 amps is for both units combined.

55 amps refers to the maximum current the wire can carry for non continuous loads.

However, EVs are considered continuous loads.

In the case of continuous loads you can only draw 80 percent of the maximum circuit ampacity. 55*.8=44.

 

[ATPMSD]

I wonder if you could also cheat the system and say that loadsharing is enabled, but only have one participant, and still set the max current in 1 amp increments!

Good thought but no. I tried to see if this would work and you can not set a load limit unless you add at least one additional wall connector.

 

[ATPMSD]

No 44 amps is for both units combined.

55 amps refers to the maximum current the wire can carry for non continuous loads.

However, EVs are considered continuous loads.

In the case of continuous loads you can only draw 80 percent of the maximum circuit ampacity. 55*.8=44.

I think you missed the point. I do not use load sharing and was trying to confirm from what I have read.

When using load sharing you set the maximum capacity (breaker size) for use by all units in the share pool, the 80% number does not apply. For example if I ran an 80 amp circuit to the subpanel where each wall connector braniched from, then the circuit limit would be set to 80 amps to match the breaker. With just one unit online an 80 amp circuit is available but since the wall connector is set to 60 amps it uses only 48 amp. If two units are online then each is told they are on a 40 amp circuit and each wall connector would use only 32 amps (80%).

Can someone who is using sharing confirm or correct this?

 

[terranx]

I wonder if you could also cheat the system and say that loadsharing is enabled, but only have one participant, and still set the max current in 1 amp increments!

Tried messing with this - I don’t see a way to enable load sharing with just one wall connector, but setting the network limit to 44A while each individual connector is set to 48A does end up limiting each to 44A max

So if we can figure out a way to trick the system into thinking it’s part of a network, seems like that’d be a way to let all the 6AWG romex people to maximize their current

 

[terranx]

I think you missed the point. I do not use load sharing and was trying to confirm from what I have read.

When using load sharing you set the maximum capacity (breaker size) for use by all units in the share pool, the 80% number does not apply. For example if I ran an 80 amp circuit to the subpanel where each wall connector braniched from, then the circuit limit would be set to 80 amps to match the breaker. With just one unit online an 80 amp circuit is available but since the wall connector is set to 60 amps it uses only 48 amp. If two units are online then each is told they are on a 40 amp circuit and each wall connector would use only 32 amps (80%).

Can someone who is using sharing confirm or correct this?

All of the settings are what the actual current draw is. That should be set to 80% of what your wiring allows

In my case, I have 6 AWG MC cable supplying the sub panel feeding the wall connectors (which are also using 6AWG MC cable). So the network limit is set to 52A (80% of 65A), and the wall connectors are set to 48A each (which is the max they support).

 

[brush1]

All of the settings are what the actual current draw is. That should be set to 80% of what your wiring allows

In my case, I have 6 AWG MC cable supplying the sub panel feeding the wall connectors (which are also using 6AWG MC cable). So the network limit is set to 52A (80% of 65A), and the wall connectors are set to 48A each (which is the max they support).

What size breaker do you have feeding your sub? I was checking my setup and I'm going to be replacing a NEMA 14-50 plug so I may be limited to a 50 amp feeder breaker. So in this case I'm just trying to figure out the best approach to get maximum charging using power-sharing.

I'm thinking feeding the sub panel with the 6/3/ 50 amp feeder, then doing two separate 50 amp breakers in the sub and feed those to the wall connectors. Limit the power sharing to the two connectors to 40 amps and call it a day. Would that work?

 

[ATPMSD]

the wall connectors are set to 48A each (which is the max they support).

You cannot set the WC to 48A, your choices are 15, 20, 30, 40, 50 or 60 so please elaborate.