I have a 400amp 3 phase 480volt feed to a panel box. I have to install battery chargers to this system. Each charger has a lable rating of 15 amps. I called the manufacturer and spoke to the electrical engineer and was told that i could install 26 chargers on this feed and it would be code compliant. I thought you could only use 80% of your total capacity. 15x26=390. Isn't 80% 320amps. Where is the code that says to only use 80% anyway. Whos right?
Industrial battery chargers
- Thread starter Timboe
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Twoskinsoneman
Senior Member
- Location
- West Virginia, USA NEC: 2020
- Occupation
- Facility Senior Electrician
This is the code I think you are looking for. But I don't think the loads you have are considered continuous so it doesn't apply.
215.3 Overcurrent Protection. Feeders shall be protected
against overcurrent in accordance with the provisions of
Part I of Article 240. Where a feeder supplies continuous
loads or any combination of continuous and noncontinuous
loads, the rating of the overcurrent device shall not be less
than the noncontinuous load plus 125 percent of the continuous
load.
Is the 15 amp load single phase or three phase?
Non continuous loads can be connected at 100% of the feeder rating. Continuous loads, runs more than three hours at the rating, load at 80%. The max rating of the charger may be for special duty, like fast charging a dead bank. Slow and float charging most likely draw less. If you look at the characteristic charging duty cycle, what expectation is there that the chargers will run at 100% for three hours? It's probably a noncontinuous load.
Non continuous loads can be connected at 100% of the feeder rating. Continuous loads, runs more than three hours at the rating, load at 80%. The max rating of the charger may be for special duty, like fast charging a dead bank. Slow and float charging most likely draw less. If you look at the characteristic charging duty cycle, what expectation is there that the chargers will run at 100% for three hours? It's probably a noncontinuous load.
Twoskinsoneman
Senior Member
- Location
- West Virginia, USA NEC: 2020
- Occupation
- Facility Senior Electrician
I think you have your answer. You haven't said the application. Unless these chargers will run at max rated for 3 hours or longer they are non-continuous.
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