Lights

[millwrightdude]

I'm going to be adding some lights to my Case/Ih C50 real soon. I would like to know when and where to install relays. I want to add 2 lights to the rear and 2 light in the front

 

[Soundguy]

If you want them on with the tractor main lamps, then find the existing lamp switch wire and tap off there and let that power the field of the relay or relays you are using. size the relay/(s) for the lamp load, and size the wire gauge accordingly, taking into account length of run.. I think I'd go 10ga minimum or even 8g.. put the relays where they will be protected.. perhaps near the tractor's electrical panel... etc.

when you turn on the tractor headlamps, it will energize the fields onthe relay and turn them on as well. tap power for the relays from wherever the oem lamp switch grabs power as long as the wire point is rated for the extra load.. or if not, then from the hot side of the solenoid which is where the alternator usually hits. make sure you fuse the lines appropriatly.. I prefer to fuse them as close to the power source as practical.

soundguy

 

[DELInstallations]

without figuring my ohm's law vs. lamp sizing, I'd say that awg is overkill+1. I'd say that 12 or 14 should be plenty even factoring in the drop based on wire length and what the majority of lights would draw, even a pair.

Pigtail the relay to the existing switch, then pull power where you see fit, if you want to turn on with the existing lights, otherwise you can run a separate circuit and either run a straight toggle or via a relay.

 

[Soundguy]

how can you say what is too big or too small without knowing the wattage of lamps he's running and how long the wire run is? 10awg is a good safe bet if you want brite lights and don't want a 15' chassie heater disguised as a feed wire to a bank of lamps..

break out ohm law? e=ir p=ei p/e=i

use the last one with total wattage and source volts to figure fuse and wire size.
i've yet to ever have an oversized wire cause a problem with lighting.. I have however seen lotrs of problems with undersized conductors...


soundguy

 

[mjncad]

OK, let's assume the OP is going to use common 55W halogen work lights. If that is the case, #14AWG will be just fine on the light side of the relay, and #18AWG for the switch side of the relay.

Figure 4.6 AMPS per light. Just make sure to fuse the light's side of the relay, and if you are using a separate circuit off the battery for the switch(es) controlling the relay(s), then fuse the switch(es) too. A single 5 AMP fuse is fine for switch(es).

I also suspect the OP intends to keep the lights' wiring as short as possible.

 

[BXRICK]

I'm with Chris on this one - if in doubt, round up on wire size. And since we don't have all the information, we're in doubt.

It really isn't any harder to run a slightly larger wire than a slightly smaller one (until you get to #0 vs. #2 type scenarios).
The only reason to try to justify a slightly smaller wire is because you already own a spool of it, and you don't have any of the bigger stuff lying around.
Next time you need s pool, buy a spool of the bigger stuff instead.

The factory has an incentive to use the smallest wire possible because they use a lot of it.
When adding on, we'er only doing one tractor (not thousands) and, we don't know all the variables and tolerances and safety margins the factory engineers used. It's easy to play it safe with this stuff.

So:
- Round up on wire size.
- Use a relay. If you think you maybe kinda should use a relay, do so. You also can often avoid having to add in your own switches with a relay.
- Fuse any wire run that isn't fused already. And fuses should go as close to the power source as you can get them.

 

[Soundguy]

yep.. never hurts to be safe.. plus lets you have extra capacity if needed later for that extra rear worklamp you forgot to add when you ran the anemic just barely adequate wire 2 weeks before you knew you needed a couyple lamps facing backwards.. and heck, a fender mounted lamp on a swivel to look at your fenceline...

soundguy

 

[Stampeder]

I'm with MJNCAD, 14 AWG will do just fine. Remember your house is wired (at least most of them) with 14 gauge wire and rated for 15 Amps of current. That's the trip point of the breakers. Breakers and fuses are there to protect the wire from overheating and burning through the insulation. If we assume that he is using the 55 watt Halogen lights then I agree 14 AWG will do just fine. My tractors lights are running 16 gauge and that's from the factory.

 

[Soundguy]

I'm with MJNCAD, 14 AWG will do just fine. Remember your house is wired (at least most of them) with 14 gauge wire and rated for 15 Amps of current. That's the trip point of the breakers. Breakers and fuses are there to protect the wire from overheating and burning through the insulation. If we assume that he is using the 55 watt Halogen lights then I agree 14 AWG will do just fine. My tractors lights are running 16 gauge and that's from the factory.

Not an apples to apples comparison.. but...

15a at 120vac = alot more wattage of power disipation than 12vdc at 15A

still other variables too.. like stranded vs solid and single wire vs paired wires.. etc..

soundguy