Relay or not ??

[Dave K]

2003 Tige 22i Type R

I am throwing up a set of 4 lights (2 front 2 rear) on the tower this weekend. I have a switch on the dash (factory) for lights front & back. I was wondering if I really need to wire in relays??

2 lights 2x55 watts/12 volts= less than 10 amps.

Opinions...Thank You

[Fast1911]

not sure what size fuse protects the switch you are using, as long as the fuse is rated for 10-15 amps you should be fine. Keep in mind your wire size and voltage drop, probably go with a 15 amp fuse just to be safe.

[chpthril]

Go with a couple of relays. Even though those switches are rated for 20A's, the power supply for all the switches is typically daisy-chained from one to the other. You would be adding an additional 10A's to a circuit that's already powering nav lights, blower, bilge, horn, etc.

Or, run a dedicated 12V of proper fuse and wire size just to the light switch and skip the relays.

[Fast1911]

Go with a couple of relays. Even though those switches are rated for 20A's, the power supply for all the switches is typically daisy-chained from one to the other. You would be adding an additional 10A's to a circuit that's already powering nav lights, blower, bilge, horn, etc.

Or, run a dedicated 12V of proper fuse and wire size just to the light switch and skip the relays.

good point, didn't even think that the main switch feed might be daisy chained from one fuse instead of separate circuits.........


need to make sure bilge pump, blower, lights, and everything else are not on the same circuit as the one he's trying to tie into......

[whitlock87]

I would use relays.
Switches run relays, relays run lights. No chance of damage to anything else.

[Dave K]

If I didn't use relays I would run a 12 gauge fused wire to the switch and then 14 ga up to the lights. Fuse at the battery and 1 fuse on the light side of the dash switch?? Sound ok?

[chpthril]

If I didn't use relays I would run a 12 gauge fused wire to the switch and then 14 ga up to the lights. Fuse at the battery and 1 fuse on the light side of the dash switch?? Sound ok?

Sounds ok!

[Fast1911]

If I didn't use relays I would run a 12 gauge fused wire to the switch and then 14 ga up to the lights. Fuse at the battery and 1 fuse on the light side of the dash switch?? Sound ok?

If your running a new circuit from the battery then you really dont need the relay. You can also use 14 gauge on both sides of the switch for 2 lights. If you plan on adding more lights in future run a 12 or 10 gauge to both sides

[Dave K]

If your running a new circuit from the battery then you really dont need the relay. You can also use 14 gauge on both sides of the switch for 2 lights. If you plan on adding more lights in future run a 12 or 10 gauge to both sides

I suppose that maybe I should run a 10 ga to a distribution block under the dash and I would have more power for additional accessories.

Thanks

[Fast1911]

I suppose that maybe I should run a 10 ga to a distribution block under the dash and I would have more power for additional accessories.

Thanks

Basically this is how it breaks down:

14 gauge = 15 amp rating

12 gauge = 20 amp rating

10 gauge = 30 amp rating

8 gauge = 50 amp rating

These numbers can fluctuate a little depending upon the insulation type on the wire itself, this is a decent guide though