Mike Dolt Enterprises
Mike Dolt Enterprises
User: hhsting, Location: Glen bunie, md, us
Asked on: Friday, May 28, 2021 at 10:43 am EDT
Answered on: Thursday, June 20, 2024 at 10:59 am EDT
Question: I have pizza shop that has Commercial kitchen. SEF-1 fan inside duct for smoke/economizer with 5hp breaker sizing 208V three phase. What is the breaker size for this according to NEC 2017? 40A is provided
No, 40A is not correct.For a 5hp motor, the full-load current (FLA) can be calculated using the following formula:FLA = (HP x 746) / (Voltage x Efficiency x Power Factor)Assuming an efficiency of 90% and a power factor of 0.8, we get:FLA = (5 x 746) / (208 x 0.9 x 0.8) = 22.1AAccording to NEC 2017 Table 430.250, the minimum branch circuit size for a motor with a FLA of 22.1A is 30A.Therefore, the correct breaker size for the SEF-1 fan is 30A. Flag for review