Condo vehicle charging stations

[Sparky366]

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?

 

[LarryFine]

Let's start with a few Qs: What code cycle?

What's the source(s) and distances? (panel quantity)

 

[junkhound]

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.

 

[Dennis Alwon]

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?

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.

 

[Sparky366]

Let's start with a few Qs: What code cycle?

What's the source(s) and distances

 

[Sparky366]

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 .

 

[Sparky366]

Here is the section

Is a car charger similar say to and electric heater element as in full load as soon as you plug in?
I can envision a time where everyone shows up at the same time and plugs in .

 

[Sparky366]

Let's start with a few Qs: What code cycle?

What's the source(s) and distances? (panel quantity)

By the time things get going it will probably be 2020 code

 

[Dennis Alwon]

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]

I’m still trying to work out this site so don’t mind if I’m not sure who I am replying to .

 

[Sparky366]

So I’m looking at a 600 amp service for 10 -40amp car chargers . (why doesn’t that sound correct?)

 

[Dennis Alwon]

So I’m looking at a 600 amp service for 10 -40amp car chargers . (why doesn’t that sound correct?)

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?

 

[ron]

So I’m looking at a 600 amp service for 10 -40amp car chargers . (why doesn’t that sound correct?)

Is the Condo 120/240V single phase service or three phase 120/208V? You are right if single phase and no interconnected chargers like Dennis pointed out to control the load.

 

[LarryFine]

By the time things get going it will probably be 2020 code

Here, the code cycle enforced is the one in use at the time of permit application.

 

[GeorgeB]

Etc, specific customer analysis called for IMO.

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.

 

[LarryFine]

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.

 

[Sparky366]

In sitting down with them this morning to go over site.

 

[Sparky366]

There are no permits at this point