04-13-2017, 08:27 PM
If you fuse it at twice the normal draw, it may not blow under overload conditions. Consider that a slow blow fuse will carry 110% of its rated current indefinitely, and may take two minutes or more to blow at twice rated current. You probably want to spec the fuse closer to the actual draw.
If the radio was drawing .78A I would go with a 1A slow blow. If the fuse is easily accessible you can experiment with the lowest rated fuse that holds under normal operation, which will give the greatest safety factor.
A fast blow fuse will give more protection, but will typically blow under the current surge at turn on. Raising the current rating of the fast blow will prevent turn on blowing, but the higher rating may not give overload protection, which defeats the whole purpose.
If the radio was drawing .78A I would go with a 1A slow blow. If the fuse is easily accessible you can experiment with the lowest rated fuse that holds under normal operation, which will give the greatest safety factor.
A fast blow fuse will give more protection, but will typically blow under the current surge at turn on. Raising the current rating of the fast blow will prevent turn on blowing, but the higher rating may not give overload protection, which defeats the whole purpose.