Load Calculation

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gstiles

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electrician
Hi everyone I am in need of a little help. Load calcutaions have not been a strong suit of mine and needing some help. Have someone wanting to install a feed/panel for 20 car chargers that are 240v 50a each and asking for a load cal. Load should be figured at 125% but for a load calculation....any help at all? Much much appreciated thank you
 
if each unit is 50 amps then you need 1000 amps x 125% of the largest =1063amps. that's assuming they will all be on at the same time. Not sure about a feeder on this.... you may need to take 125% of the entire load which would be 1250 amps. I am sure David will chime in. He is good at the calcs
 
If I may, your ampere (240 kw) load will be depending on the feed being 3 phase or single phase.
On single phase, Dennis' number would be good.
There has been discussion her about the load being "continuous" and I'll have to research that.
IMHO, it would not be a continuous load.
Edit: Art 625 does call for the feeder calculation to be continuous duty.. so 300 kw, as Dennis says 1250 amp
(be a 830 amp 3 phase 240v feeder but you can't balance 20, chargers so 830 would be a little shy)
(
 
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This seems like a simple thing but I am growing frustrated about it for some reason and struggling to put this together. The customer is asking for a new service or whatever is needed to accommodate 20 chargers in a parking garage. The utility company is asking for a load cal before going any further.
 
For power company purposes, I'd tell them 250kw.
It may get interesting. You may want to do a little research in advance. See if the units are designed to operate on 208. With that load (250kw) POCO may not offer you single phase 240 and will possibly want to give you 208 3 phase...If you chargers won;t operate on 208, it may be "meeting" time.
 
@augie47

625.42 Rating. The equipment shall have sufficient rating to
supply the load served. Electric vehicle charging loads shall be
considered to be continuous loads for the purposes of this article.
Where an automatic load management system is used, the
maximum equipment load on a service and feeder shall be the
maximum load permitted by the automatic load management
system.
Click to expand...
 
I didn't even think about 3 phase since he said 240v but it could have been a delta. Commercial service that is single phase and the power company wont accommodate? Sounds strange to me...

3 phase would mean 14 units would be on 2 phases so you wouldn't use 20
 
Dennis Alwon said:
I didn't even think about 3 phase since he said 240v but it could have been a delta. Commercial service that is single phase and the power company wont accommodate? Sounds strange to me...

3 phase would mean 14 units would be on 2 phases so you wouldn't use 20
Click to expand...
I think gstiles said single phase.
 
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