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Fuse position in circuit

Practical Motorsport Wiring - Club Level

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You guys recommend putting the fuse on the output side of circuit between relay and load device? As opposed to between power supply position 30 on relay.

Hello Adam,

OEMs do it both ways. If you are running multiple circuits off one relay, running fuses after the relay allows for different current limits on the individual circuits (you could also add a large fuse before the relay of the combined current limit if you wanted to). Alternatively, if you are running one circuit off the relay, putting it before will protect the wire between the 12V & fuse if that was ever to short, although often the proximity of the the fuse and relay is so close, (being together in a power distribution box) it doesn't make much of a difference in the amount of protection it offers.

Normal practice is to have the fuse as close as practical to the battery/power supply and/or bus.

However, there is some variation as different circuits and applications will have different requirements.

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