"Removing" a load from a service to make room for a new load

U

UBG

Member
Location
So Cal
Occupation
Electrician
I think the answer to this could come down to "whatever the AHJ wants", and I've made that call and I am waiting for them to respond...but I'm throwing it out here too.

Customer has 200A service for their single family home. They'd like to add an EVC at a 40A or 48A capacity, but they don't have the ampacity in that service to add it with the existing loads.

A big chunk of that existing load is a steam shower that they never use. Removing the steam shower would free up enough ampacity on the service to allow the addition of the EVC. What would you consider sufficient "removal" of the steam load to be, in order to satisfy the NEC?

They'd like flexibility for their future resale of the property...maybe a potential buyer likes steam, and doesn't need an EVC...well, here you go, we'll take our EVC with us, and reconnect the steam generator for you, and voila. For practical purposes, they'll never use the steam, so it's as if it didn't exist...but "we promise" is not an allowed approach in the Code.

So, for load calculation purposes, what would you all say needs to be done in order to "remove" the steam generator from the service and allow the new EVC load to be installed?
  1. Remove the ungrounded conductors from the breaker, leave capped off and taped/labeled in panel, leave steam unit as is?
  2. Same as above, but also remove conductors from lugs in steam unit, cap and label in the wiring compartment?
  3. Remove the steam unit itself, but conductors can stay, capped and labeled in panel & jbox?
  4. Remove conductors completely from conduit, but steam unit can stay as is?
  5. Remove everything, as if it was never there?
Thanks for reading and responding
 
You could also, depending on if they don't mind spending the money, install a gutter with splices to a "transfer switch" D/C or a two breaker panel with kirk key interlock. So that when someone wants to use the steam shower the EVSE breaker must be in the off position and vice versa.
 
winnie said:
This.

'Chargers' with load management are available to solve this exact problem. If someone decides to use the steam shower, the EV simply charges more slowly. The service never sees an overload.

Jonathan
Click to expand...
The ‘charger’ would need the capability to sense the current on the incoming service (or feeder). Does such a beast exist?

The ones I’ve seen with load management capability only interact with another like unit, not other loads.
 
UBG said:
I think the answer to this could come down to "whatever the AHJ wants", and I've made that call and I am waiting for them to respond...but I'm throwing it out here too.

Customer has 200A service for their single family home. They'd like to add an EVC at a 40A or 48A capacity, but they don't have the ampacity in that service to add it with the existing loads.

A big chunk of that existing load is a steam shower that they never use. Removing the steam shower would free up enough ampacity on the service to allow the addition of the EVC. What would you consider sufficient "removal" of the steam load to be, in order to satisfy the NEC?

They'd like flexibility for their future resale of the property...maybe a potential buyer likes steam, and doesn't need an EVC...well, here you go, we'll take our EVC with us, and reconnect the steam generator for you, and voila. For practical purposes, they'll never use the steam, so it's as if it didn't exist...but "we promise" is not an allowed approach in the Code.

So, for load calculation purposes, what would you all say needs to be done in order to "remove" the steam generator from the service and allow the new EVC load to be installed?
  1. Remove the ungrounded conductors from the breaker, leave capped off and taped/labeled in panel, leave steam unit as is?
  2. Same as above, but also remove conductors from lugs in steam unit, cap and label in the wiring compartment?
  3. Remove the steam unit itself, but conductors can stay, capped and labeled in panel & jbox?
  4. Remove conductors completely from conduit, but steam unit can stay as is?
  5. Remove everything, as if it was never there?
Thanks for reading and responding
Click to expand...
What makes you think they don't have the ampacity in the service?
 
retirede said:
The ‘charger’ would need the capability to sense the current on the incoming service (or feeder). Does such a beast exist?

The ones I’ve seen with load management capability only interact with another like unit, not other loads.
Click to expand...

Short of putting some type of PCS or EMS, you are correct. You would need to put in a system that monitors both and then tells the charger to reduce output.
 
retirede said:
The ‘charger’ would need the capability to sense the current on the incoming service (or feeder). Does such a beast exist?

The ones I’ve seen with load management capability only interact with another like unit, not other loads.
Click to expand...

I'm already outside of my comfort zone, since I've not had to install any of these.

Wallbox and Emporia both claim to have units that monitor the home energy consumption and adjust their output to limit total consumption.

-Jonathan
 
winnie said:
I'm already outside of my comfort zone, since I've not had to install any of these.

Wallbox and Emporia both claim to have units that monitor the home energy consumption and adjust their output to limit total consumption.

-Jonathan
Click to expand...
Now that you mention it, I recall Emporia having it available. Wasn’t aware about Wallbox.
 
retirede said:
The ‘charger’ would need the capability to sense the current on the incoming service (or feeder). Does such a beast exist?

The ones I’ve seen with load management capability only interact with another like unit, not other loads.
Click to expand...
Absolutely yes. I use Wallbox for this most often: dynamic responsive loads.

The big barrier though is we don't always have access to the incoming SE conductors, as they are in tag locked utility only sections.
The utility can't be bothered to give official access. Placing the CT clamp sensors on the overhead weatherhead works, but is really ugly and fragile.
 
Elect117 said:
You could also, depending on if they don't mind spending the money, install a gutter with splices to a "transfer switch" D/C or a two breaker panel with kirk key interlock. So that when someone wants to use the steam shower the EVSE breaker must be in the off position and vice versa.
Click to expand...
I'd rather see this, solid and professionally wired, than the "Neocharge" splitters !
 
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