Fuse the Wire or Fuse the Device?

Don Johnstone wrote:

The power requirements of all my instruments are well
below 3 amps.

Have you checked the amperage while the radio is transmitting? A glider
with a GPS (.2 -.3 amps), PDA (.4 to .8 amps), vario, and a good radio
transmitting (Becker 4201 2+ amps) can draw 3 amps, so you might be
closer to the fuse rating than you think. And if you turn on the T&B
(.7-.9 amps), you will almost surely exceed 3 amps during transmission.

I suggest you go to at least 5 amps, since you use smaller fuses to
protect the individual devices. This will also reduce the voltage drop
across the fuse, a good thing.
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Eric Greenwell
Washington State
USA