Condo vehicle charging stations

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Sparky366

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Wayland ma usa
I have a customer who wants to install maybe 10-40A 240v charging stations
would a service for these stations need to be rated at125% or is there any derating on service for multiple charging stations? Are they calculated a 100% load?
 
Let's start with a few Qs: What code cycle?

What's the source(s) and distances? (panel quantity)
 
Main Q is on a more practical basis vs. simply blindly following an arbitrary code. For instance, is the customer a delivery service where 10 vehicles all show up at 6 PM and plug in? Or, a hospital parking lot where most of the elec vehicle slots are empty 80% of the time. 124% in first case even if code says 50% derate. Hospital case could change with time as more EVs on the road.

Etc, specific customer analysis called for IMO.
 
Sparky366 said:
I have a customer who wants to install maybe 10-40A 240v charging stations
would a service for these stations need to be rated at125% or is there any derating on service for multiple charging stations? Are they calculated a 100% load?
Click to expand...

Here is the section

625.41 Overcurrent Protection. Overcurrent protection for
feeders and branch circuits supplying equipment shall be sized
for continuous duty and shall have a rating of not less than
125 percent of the maximum load of the equipment. Where
noncontinuous loads are supplied from the same feeder, the
overcurrent device shall have a rating of not less than the sum
of the noncontinuous loads plus 125 percent of the continuous
loads.
Click to expand...
 
The condos service is probably not enough for that many chargers
and distances for chargers from source maybe 300 feet closer for some and farther for others
I am thinking a separate service for chargers would be needed .
 
I am not sure how the chargers are designed but the code calls for 125%. There are units that can be interconnected so that one branch circuit can be wired to 3 or 4 stations however, the units talk to each other and control the load. Thus you will not be getting a full load to the cars if all 4 are being used.. That may not be ideal but perhaps 2 units per circuit would work. If this feature is not built into the charger then you can buy a separate system that will interconnect them wireless or with some low voltage cable
 
Sparky366 said:
So I’m looking at a 600 amp service for 10 -40amp car chargers . (why doesn’t that sound correct?)
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Well think about it. Is it possible for everyone to come back in the evening after work and charge their vehicles? I could see them all on at the same time. Get 30 amp units and you can go with 400 amps.

I agree that most of the time you will probably never see all the units running together but I don't believe there is a calculation demand factor for this.

Also if the unit states 40 amps is that what the unit is actually using or does that have the 125% built in?
 
junkhound said:
Etc, specific customer analysis called for IMO.
Click to expand...

Very much, perhaps more for business than code issues FIRST.

I can picture a business owning one unit and having 20 Uber vehicles swapped among the 10 chargers as the batteries are exhausted.

I can picture 5 units with 2 car garages and 2 EVs per unit.

I can picture 40 units with parking allowing a charger reaching one of 4 EVs and the owners not fighting over who and when.

SOME chargers (Tesla comes to mind) can intercommunicate and limit premise (feeder) load.

I don't think you will get useful answers until you can get better info from the condo association management and give it to us here.
 
There's another approach: Tell them how many chargers they can get for each step in the providing power options.

I.e., X stations on a 200a panel for $XX, Y stations on a 300a panel for $YY, ETC.
 
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