EV charger load calc

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ElecBolt12

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Nj
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Electrican
It is an existing house with a 200amp panel and the inspector wants a load calculation because we are adding a EV charger. How would you do something like this?
Will be running six gauge wire on a 50 amp breaker to 240V outlet. I assume he wants to see if the panel can hold the extra load. What would be the steps to complete this load calculation?
 
ElecBolt12 said:
It is an existing house with a 200amp panel and the inspector wants a load calculation because we are adding a EV charger. How would you do something like this?
Will be running six gauge wire on a 50 amp breaker to 240V outlet. I assume he wants to see if the panel can hold the extra load. What would be the steps to complete this load calculation?
Click to expand...
You need to do an Article 220 calc.
 
Tip #1 use the alternate calculation
Tip #2 see the examples in the annex
Tip #3 take pictures of nameplates for HVAC, Dryer, range, etc
 
What is the alternate calc?
I know the serivce load calc. Like wouldn’t just add the EV charger into the service load calc ex:9.6kw
For a total load of the service?
 
There are two different residential calculation methods -- Standard and Optional. The Optional usually comes in with a lower number. Once you've gone over 10KW, most new things add 40% of their nameplate to the load calc. So a 10KW car charger would add 4KW (or about 17amps) to the load calc.
 
ElecBolt12 said:
What is the alternate calc?
I know the serivce load calc. Like wouldn’t just add the EV charger into the service load calc ex:9.6kw
For a total load of the service?
Click to expand...
There is "A Pocket Guide to All-Electric Retrofits of Single-Family Homes" with some interesting ways to avoid service upgrades with clever load calcs.

The NEC requires twice as much power allocated to separate appliances, such as oven and range (19,200W) vs combined range and oven (9,600W). Similarly, attaching a microwave oven to the wall triggers an extra, dedicated circuit vs just placing the microwave on the countertop or doghouse cabinet.

Power-sharing car chargers can eliminate service upgrades, by sharing a circuit with similar electric appliances. Car charging automatically resumes when the other appliance is finished.

Circuit-sharing plugs (e.g. NeoCharge, Dryer Buddy, SplitVolt, or hard wired SimpleSwitch) allow one existing high voltage (240V) outlet to power both a car charger and a laundry dryer, or a water heater and a range.

Manual transfer switches can also be installed next to the main fuse box.
 
ramsy said:
There is "A Pocket Guide to All-Electric Retrofits of Single-Family Homes" with some interesting ways to avoid service upgrades with clever load calcs.

The NEC requires twice as much power allocated to separate appliances, such as oven and range (19,200W) vs combined range and oven (9,600W). Similarly, attaching a microwave oven to the wall triggers an extra, dedicated circuit vs just placing the microwave on the countertop or doghouse cabinet.

Power-sharing car chargers can eliminate service upgrades, by sharing a circuit with similar electric appliances. Car charging automatically resumes when the other appliance is finished.

Circuit-sharing plugs (e.g. NeoCharge, Dryer Buddy, SplitVolt, or hard wired SimpleSwitch) allow one existing high voltage (240V) outlet to power both a car charger and a laundry dryer, or a water heater and a range.

Manual transfer switches can also be installed next to the main fuse box.
Click to expand...
Where in the NEC does it say that a transfer switch can be used to eliminate one of the loads on the switch from the load calc? (e.g., EV/Dryer transfer switch)
 
ESolar said:
Where in the NEC does it say that a transfer switch can be used to eliminate one of the loads on the switch from the load calc? (e.g., EV/Dryer transfer switch)
Click to expand...
Grasshopper must learn more code jargon

Try the key phrase:

"Where the circuitry is interlocked"
 
tom baker said:
Tip #1 use the alternate calculation
Tip #2 see the examples in the annex
Tip #3 take pictures of nameplates for HVAC, Dryer, range, etc
Click to expand...
#4 Charge the customer for the load calculation work.
 
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