Remember that the fuse needs to be inside a weatherproof enclosure if it's in the engine compartment. They make special enclosures for that sort of thing- just "any old fuse holder" won't do.

Also, the wiring and connections to the battery should be done "properly", i.e., they make special heavy-duty attachments just for hooking your amp power cables up to your car battery. If you jerry-rig something, it's bound to get corroded quickly and you'll start having odd intermittent problems with noise etc.

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Tony Fabris