[ItsPeteReally]

Don't worry, Suby Fan is proposing a wiring resistance test, not an alternator test.

If you have a fully charged battery then the alternator output will automatically be less than 10 amps. It's difficult and possibly dangerous to try to measure the alternator output current anyway.

If you can maintain 14.4 volts (or close) across the battery with the engine running, and the headlights on, then your charging system should be fine.

If you turn on more stuff, like the rear screen defroster and heated seats (if you've got them), etc. etc. you might see the voltage across the battery drop, but revving the engine a little more should bring it back up. If you turn on everything you can find you might just find that eventually the alternator can't keep up with the current demand and then the battery voltage will drop.

Really, if you find a significant voltage drop across any part of your wiring (not just the part that Suby Fan described, and I would certainly include the earthing (grounding) strap from the battery to the car body in this too) then it's a good plan to find out why.

The part that is under the most strain under this very severe test is the fusible link (mounted with the other main fuses next to the engine) which protects the alternator from delivering too much current. If your car is anything like mine you might see that the lid of the fuse box shows some pre-existing signs of heat damage from the current flowing through this link.

Do not bypass this link in an attempt to make things better, it's there specifically to protect your alternator from meltdown from supplying too much current.