Fuse Derating Guidelines

Recommended Fuse Stress Factor [Fuse Derating]

Fuse Current Rating .... Fuse Derating Factor
2 - 1.5 amps 0.50%
1 - 1.5 amps 0.45
0.5 - 0.75 amps 0.40
0.375 amps 0.35
0.25 amps 0.30
0.125 amps 0.25

Derate a fuse by multiplying the rated current by the derating factor.
Derate an additional 0.5%/C above 250C

Keep in mind that a fuse holder, if used should be derated as well. When selecting a fuse holder be sure that the holder can withstand the maximum fuse rating for voltage and current. The fuse holder could melt trying to with stand the power dissipated by the fuse before the fuse opens.
No derating data has been found for a Fuse Holder; How ever in many cases a connector is derated to 25% of its maximum Dielectric Withstanding Voltage. Or the dielectric should with stand Ambient Temp + Ohmic heating Temp + 50C

Fuses are specified to interrupt within a maximum of 5 seconds when driven at 200% of their rated current for nominal ratings up to and including 10 amperes. A fuse with a nominal rating of 15 amperes is specified to interrupt within a maximum of 10 seconds when driven at 200% of its rated current.
The power supply shall be capable of delivering appropriate levels of current to achieve short fusing times. There is an additional derating of 0.2%/°C for an increase in the temperature of fuse body.

Ambient temperature and fuse load percentage operation
Fuse Derating by Ambient Temperature

Fuse Manufacturers
Fuse Holder Vendors

Derating guidelines for electrical parts;
Derating Electronic Components

Ribbon Fuse

Offset Slot Fuse
Slot Fuse

Engineering Tags:
Fuse Derating,
Fuse Reliability,
Rated Current

PC motherboard

Distributor rolodex Electronic Components Electronic Equipment EDA CDROM Software Engineering Standards, BOB card Cabled Computer Bus Electronic Engineering Design Table Conversion DB9-to-DB25.
DistributorsComponents Equipment Software Standards Buses Design Reference

Modified 3/17/12
Copyright © 1998 - 2016 All rights reserved Larry Davis