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Understainding Required Protection for FR3 UL Classification

Thread starter Jerry123
Start date Nov 7, 2012

Status: Not open for further replies.

Nov 7, 2012

Jerry123

Electrical

Team,

I'm really lost on how to determine the required protection columns for the UL Classification for FR3.

We are installing a 1000KVA 13.2 - 480/277 FR3 station type transformer next to building. Under NEC 450.23 we have met all the requirements for an UL install except for the Required Protection per the UL classification Markings for FR3. I need help explaining how to calculate the Maximum I2T for Current Limiting Fuses or Required Overcurrent Protection columns.

Thanks,
JD