What Size Circuit Breaker should be used with the MEAN WELL DDR-120B-48?

8 October 2021

We were contacted by a customer wanting to use the MEAN WELL DDR-120B-48 to convert a 24V source to power a 30W, 48V power injector for another piece of equipment.

The customer wanted advice on an appropriate circuit breaker for the system and wanted some advice on current draw.  

MEAN WELL DDR-120 Series DC to DC Converter


They wanted to know if they should base the current draw on the 30W/48V=0.625A or should they take the typical DC current from your datasheet (5.6A @ 24V). 

Based on the presumption the customer wanted a circuit breaker on the 24V input to the DDR-120, we suggested a DC breaker of 2 to 3 amps. This will allow for any inrush current on startup and protect the circuit in case of a short on the output. 

Please do not hesitate to contact Power Supplies Australia if you have a question about using a MEAN WELL power supply.