Couple Relay Questions

[bikinpunk 10+ year member]

I've bought a 30amp fused relay to use for 2 amp turn-on. I was previously tapping them both into the Headunit's power wire, which was blowing fuses in the fuse box. I have two questions regarding the installation of the relay:

1. Do I need to get the power for the relay from a seperate power source OTHER than the headunit's power wire? Or can I simply tap into that wire? I'm guessing it would cause the same problem if I tap into it, but not sure.

2. How do I determine what size fuse to use with the relay? The total combined fuse rating of the 2 amplifiers is 120 amps. One has an RMS of 1000w, the other has RMS of 100x2 watts.

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[helotaxi 5,000+ posts]

If it is only used on the remote wire, the fuse rating of the amps is irrelevent. The current drawn by a remote turn on is usually only on the order of a hundred milliamps or so. A 1A fuse for the relay should be plenty.