Electrical – Should power supply be fused on input and outputs

fusespower supply

I'm building an automation control panel. It uses a 120VAC to 24VDC power supply to power several IO cards and signal lines. The entire system will draw less than 500mA when in operation.

This PSU is rated to output 24VDC at up to 5A. The sticker also states that it draws up to 2.6A on the input side.

I have already installed a fuse on the input side, rated for 2A.

Should it also have a 5A fuse on the output? or will the 2A input fuse open if the output is overloaded/shorted?

What is the best practice in this situation?

Thanks!

Best Answer

The power supply is most likely already protected on the primary side. Check the spec sheet.

Since your secondary load is quite small compared to the capacity of the secondary, a best practice is to install secondary protection at the planned load in order to protect the load elements and associated wiring, rather than the supply.

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