Fuse Values

[Tony Hunt]

There are 2 fuseboxes in my GTD, and I haven't disturbed any of the fuses - yet.
It's fairly commonly known that some parts of the GTD system are unduly stressed by the amount of current they are asked to conduct - ignition switch, aircon switch, light switches and so on, and I have been installing fused relays in key circuits to cut down on these loads.
I'm now in the reverse situation, where I have much reduced currents flowing through the fusebox. The other day I inadvertantly shorted out a circuit, which cooked the lamp switch concerned and some wiring, but without blowing the fuse.
So, can anyone help with a rule-of-thumb for fuse values? It's easy to measure circuit loads with an ammeter, so what should I set the new fuse to? Twice the maximum current load, 1.5 times? 3 times?

[Bob Putnam]

If there's an electric motor in the circuit, 2X should cover the load. No motors: 1.5X should do it.

[Tony Hunt]

Many thanks, Bob. Exactly what I needed to know.
May I also add that any circuits with HID Xenon bulbs - main or dipped - should also have extra capacity because of the high starting currents. I'd probably treat them as 'motors'.