220.87 Determining Existing Loads

[jim dungar]

I have found the optional calc pretty favorable to EVSE's.

Can you clarify what you mean by 'sliding window' say that for 60 1 min values say every 5th minute reads at 10 and all the other values were 2.

A sliding windows has no beginning and end, where the counting stops and then starts again.
interval 1 = minutes 1 to 15
Interval 2 = minutes 2 to 16
Interval 3 = minutes 3 to 17
and so on.

This methodology will always produce the interval(s) that is higher than any other method.

In your case:
Interval 1 = 1+1+1+1+5+1+1+1+1+5+1+1+1+1+5 = 27
Interval 2 = 1+1+1+5+1+1+1+1+5+1+1+1+1+5+1 = 27
Interval 3 = 1+1+5+1+1+1+1+5+1+1+1+1+5+1+1 = 27

In wwhitney's case
Interval 1 = 0+0+0+0+0+0+0+0+0+0+0+0+0+0+1 = 1
Interval 2 = 0+0+0+0+0+0+0+0+0+0+0+0+0+1+1 = 2
Interval 3 = 0+0+0+0+0+0+0+0+0+0+0+0+1+1+0 = 2
....
Interval 15 = 1+1+0+0+0+0+0+0+0+0+0+0+0+0+0 = 2
Interval 16 = 1+0+0+0+0+0+0+0+0+0+0+0+0+0+0 = 1

 

[tortuga]

When doing a load calculation by hand I came to 79 Amps.

Can you share the details of the load calc? I have found 220.83(A) to be pretty favorable to installing additional loads.
There are also fewer questions on methodology as 220.83(A) is extremely simple, although it does take some elbow grease to gather all the nameplates and with existing HVAC I have to be sure to not use the MCA.

 

[tjdilly]

Are you talking about the Wallbox? I am eagerly waiting for ChargePoint to include a reasonably priced load management system that could be added to their EVSE.

I just purchased a DCC-12 load shedder for $800 for a job. This thing is a pair of contactors, a circuit board, and a couple CT’s. It just shuts the charger down dead when the load approaches 80% of the service ampacity. I don’t like anything about this.

Chargepoint already has this for their commercial lines, it's included within the startup programming and software. You can set the chargers to limit the current draw on a branch circuit, panel, and service level.

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