Fuse Taps

[Greenie]

I am considering using a fuse tap on my interior fuse panel to activate a relay for some auxiliary lights. A fuse tap appears to offer a cleaner connection than chasing down some other source of switched power and splicing wires.

Is this a safe alternative and if so which side of the fuse connection is the hot side and which is the load side as observed when the cover is removed? I would like to utilize the existing fuse as protection for this new connection thus the question on which side of the fuse to make the connection.

[los211]

The best way is to use a digital meter to find the input side of a fuse. Take out the fuse you are going to use, ground one lead of the meter and probe each terminal where the fuse was while cycling the key to the on/acc. That will give you what you need. Some fuse boxes have spare slots in them and you may be able to set up the circuit that way. Using a fuse tap may cause that circuit to get too hot an melt the box. But if you are only using it to operate a relay there shouldn't be any issues like that. Just make sure the current draw on the circuit you are adding does not go above the amperage of the existing tie in circuit and don't change the fuse to a higher rating. Also you could add a fuse inline to the relay to protect the vehicle if the relay should fail.

[SE2000]

Put the tap on the supply side, not the load. Your new circuit can have its own fuse.
That way you won't affect the other circuit.
Since it is a relay and if you tap something you could live without then maybe doing the other way will be ok.
Is your plan to make a switched power out of non switched circuit?