I have a piece of UV disinfection equipment at a treatment facility we are designing the electrical connections to. We provide a single point connection to the equipment power terminals. The load is say 5KVA power draw and 480V 3-phase voltage. The equipment does not have a local overcurrent protection device and is to be provided by the others. Hence we need to note the breaker / circuit size. The manufacturer does not indicate the required overcurrent protection size (asked them). Hence, would the circuit be designed per article 210.20(C), which would then take us to table 240.3. Per the table, would this be a branch circuit or an Industrial machine?
If a branch circuit, we are back to 210.20(A). Now we need to ask the question if the load is continuous or not. Regardless, both would calculate out to be a 15A breaker (smallest breaker size) and conductors. Would still specify #12 conductors though. However, this would be the minimum size. What determines the maximum? Since the manufacturer did not provide any input on the OCPD, what would keep us from noted a 20A or even a 50A circuit?
If this would be considered an industrial machine, article 670 is now in play. However, there does not appear to be any motors, just UV lamps. 670.4(C) notes if no protection is provided with the machine, refer to 430.52 and 430.53. However, this may not be applicable since we don?t think there are motors. Even if there are, all we know is the manufacturer noted the load as being say 5KVA power draw.
Not sure what direction to proceed.
If a branch circuit, we are back to 210.20(A). Now we need to ask the question if the load is continuous or not. Regardless, both would calculate out to be a 15A breaker (smallest breaker size) and conductors. Would still specify #12 conductors though. However, this would be the minimum size. What determines the maximum? Since the manufacturer did not provide any input on the OCPD, what would keep us from noted a 20A or even a 50A circuit?
If this would be considered an industrial machine, article 670 is now in play. However, there does not appear to be any motors, just UV lamps. 670.4(C) notes if no protection is provided with the machine, refer to 430.52 and 430.53. However, this may not be applicable since we don?t think there are motors. Even if there are, all we know is the manufacturer noted the load as being say 5KVA power draw.
Not sure what direction to proceed.