Product Line:
Mini Power-zone
Environment:
Low Voltage Transformers
Cause:
Looking at MPU15S40F which has a 2-pole HDL breaker. The source voltage is a corner-grounded Delta which requires a 3-pole circuit breaker. Need to know if it can be swapped out with a 3-pole version.
Resolution:
The MPUs have not been UL tested and approved using a 3-pole main breaker in the single-phase units. So since they are UL listed as built with the HDL26060, we can not advise a customer to change the design on them. The hole pattern is also different on the 2-pole and the 3-pole HDLs, so the sheet metal back pan would have to be physically re-drilled to accommodate the larger breaker, which is an even further physical modification we can not endorse. The UL rules and regulations are our guiding principle regarding modifications to Transformers in almost every situation.
Mini Power-zone
Environment:
Low Voltage Transformers
Cause:
Looking at MPU15S40F which has a 2-pole HDL breaker. The source voltage is a corner-grounded Delta which requires a 3-pole circuit breaker. Need to know if it can be swapped out with a 3-pole version.
Resolution:
The MPUs have not been UL tested and approved using a 3-pole main breaker in the single-phase units. So since they are UL listed as built with the HDL26060, we can not advise a customer to change the design on them. The hole pattern is also different on the 2-pole and the 3-pole HDLs, so the sheet metal back pan would have to be physically re-drilled to accommodate the larger breaker, which is an even further physical modification we can not endorse. The UL rules and regulations are our guiding principle regarding modifications to Transformers in almost every situation.