EV charger Load Shedding device

[Sierrasparky]

"The feeder once it is tapped it is no longer providing providing the entire load. The internal tap portion doesn't need to meet the feeder requirements but also the extended portion from that breaker to the EV charger is a branch circuit of the device, the continuation of the apt feed from that device is still a feeder and is required to meet the limitations of a feeder and is not carrying 100% of the load as part of it is distributed to the EV charger and the 83% allowance no longer applicable.
I could acquiesce to the idea that the feeder from the first overcurrent to the tap is providing 100% of load of a dwelling unit, but from that tap to the apt is no longer carrying 100% of the load but only a proportional portion relative to the total loads applied to the apt and EV charger combined.

I am sorry I cannot agree. This is the same Feeder from the Meter a 100a or 125a. It is past the meter and is the only feeder. not a new feeder or a second. It is in fact carrying the entire load of the Dwelling unit and associated loads. as per 310.15(B)(7)(2).

 

[mike1061]

I have two questions here. 1) wouldn’t we be talking about the load being 80% with the charger in use? 2) with residential feeder conductors being sized to 83% of the service capacity, wouldn’t the permissible load be 80% of that? Meaning that a 100 amp 240 volt residential service/feeder can have conductors sized #4 which has an ampacity of 85 amps. The continuous load on those conductors should not excide 80% of that.
Thanks
Mike

 

[mike1061]

I have two questions here. 1) wouldn’t we be talking about the load being 80% with the charger in use? 2) with residential feeder conductors being sized to 83% of the service capacity, wouldn’t the permissible load be 80% of that? Meaning that a 100 amp 240 volt residential service/feeder can have conductors sized #4 which has an ampacity of 85 amps. The continuous load on those conductors should not excide 80% of that.
Thanks
Mike

I’ve just looked it does check the ampacity of the feeder including the charger. I looked at the schematic.

 

[mike1061]

I’ve just looked it does check the ampacity of the feeder including the charger. I looked at the schematic. So wouldn’t the conductors from the main disconnect to the box only have the ampacity of 80% of the 83% sized conductors? If that’s correct, would it be permissible to increase the conductors from the main disconnect to the box to #3? There for the ampacity of those at 80% would be 80 amps.

Thanks
Mike

 

[Sierrasparky]

It is still the main feeder, the size does not need to be increased. 2017 NEC

 

[Fred B]

You still are creating a tap on the individual feeders. Tap rules and sizing come into play.

 

[Sierrasparky]

So what You are playing semantics. That is not the way it works. It is the feeder of a single dwelling unit. It does not matter how many taps it makes how many feed-through panels it goes through. It is still the feeder to a single dwelling unit..... not a tap.

 

[mike1061]

Ok thanks

 

[tortuga]

Interesting I have been hearing about these but not installed one yet.
Could you dis-regard the breaker in the unit as it does not meet code, and consider the 60A circuit a 'tap'
run that to a fused disconnect next to the charger?

 

[Fred B]

Interesting I have been hearing about these but not installed one yet.
Could you dis-regard the breaker in the unit as it does not meet code, and consider the 60A circuit a 'tap'
run that to a fused disconnect next to the charger?

It is a tap, regardless of if breaker internal to component or externally. Difference only which tap rule applies. Tap rule allows for overcurrent/short circuit protection within the frame enclosure the tap is made up in, and must meet requirements of 240.21(B)(1)(1-4). If you wish to have protection elsewhere 240.21(B)(2) conditions must be met.

 

[Sierrasparky]

Interesting I have been hearing about these but not installed one yet.
Could you dis-regard the breaker in the unit as it does not meet code, and consider the 60A circuit a 'tap'
run that to a fused disconnect next to the charger?

Who says it does not meet code?
I think the code was not prepared for this device and does not adequately address it's usage.

 

[tortuga]

Who says it does not meet code?

I was referring to the reference the AHJ cited

Section 408.38 of the 2019 CEC 2017 NEC.

 

[Sierrasparky]

I was referring to the reference the AHJ cited

I got it