What is MEAN WELL’s suggestion for using an external input fuse?

All MEAN WELL power supplies come with at least one fuse on the line path1. The internal fuse is designed to handle the nominal current on the whole range of input voltages; for the same power, at low input voltages, the current drawn by the PSU will be higher:

LPV-100 input ratings (internal T 4AL-250VAC fuse)

If you want a more adapted protection for a specific input voltage, you could add an external fuse to protect the power supply. Considering that it will only protect the PSU (no other appliances connected after it), you should refer to the datasheet of the power supply and look for the typical input current under your input voltage. The fuse should be rated slightly higher than this current value. The selected external fuse should be a Slow-Blow type, this to avoid it is triggered by the inrush current of the power supply. For reference, most of MEAN WELL power supplies use type-T slow acting fuses. 

Further please take into consideration that fuses characteristics are given for an operating temperature of 25oC. Exceeding this value will lower the current rating and shorten its lifetime. Similarly, when operated in cold areas, the current rating will be increased.

Note 1: Except for DDRH-60 series

Categories: Industrial, Medical, Others
Tags: External Input Fuse, Slow-Blow

Contact us

Give us a call or fill in the form below and we'll contact you. We endeavor to answer all inquiries within 24 hours on business days.

    Required fields*