How to correctly derate DC Fuse Holders | James Explains

Correctly derating DC Fuse Holders when used in a Fuse Board or a DC Combiner Board.

James– ‘If you look at the data sheet (below) of the DF Electric Fuses, you’ll notice there are two sections around rating or derating’

DF Electric Fuses Data Sheet

The first section is the group rating, that’s when you have your fuse holders side by side. A group of 4- if you have two strings or you might have them in bigger groups, up to 20. What you have to account for, is when you have them in these groups, they have to be derated. So it’s important that you take the equation in the data sheet above into consideration when doing your board, as that will give you a derated figure. Then we have to look at the ambient temperature rating expected to be within the board or within the fuse box. Once we’ve got that derated figure from the group, if we are having them in groups of more than 4 we then take the ambient, whether it be 30 – 40 degrees and we add that to the derating that we’ve already added within the group. So just make sure that that final derated figure is above the string fuse rating because the fuse holders start at 32amps and they can very quickly drop down to 19, 17 amps etc… If you have them in groups of 12 on a 40 degree day, then you are already getting round to 17, 18 amps and if you’ve got 20amp fuses in there or optimsers or DC fuses running at 20 amps, you’re already well under’

Keep in mind the group ratings and the temperature ratings when correctly derating the fuses to go in your next Combiner Board or Fuse Box.

If you have any questions or would like to chat to us about derating fuse holders, we are more than happy to help.

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