?'s About Wiring Work Lights On A Mahindra

[MUDONTHETIRES]

Hello All,

I've been reading all the posts about wiring work lights and I think I have everything I need to install some on my tractor but have just a few questions. First, let me tell you what I have. My tractor is a 2007 Mahindra 4530 4WD. For the work lights install, I have (2) 55 watt traps, 10 gauge wire, 14 gauge wire, (1) 30 amp relay, (2) 15 amp inline fuses and a switch. One 15 amp fuse is for the 10 gauge wire going to the battery. The other 15 amp fuse is for the wire going to "the other power supply".

Here are my questions:

1. Do the 15 amp fuses need to be 30 amp fuses and if so, why?

2. The wire coming from terminal 30 of the relay goes to the battery.
Where should the wire coming from the switch going to a "fuse panel" go if you don't have a fuse panel? At least I don't think I have a fuse panel. Please pardon me as I'm not very "electrically literate". Kennyd, you would be a great help here! I have supplied the wiring diagram for my tractor in pdf format below for reference if anyone has any ideas!

Thanks a million in advance!

 

[Mike058]

If my math is right, two 55 watt lights (110 watts total) draw about 8 amps at 13.8 volts. The 14 gauge wire should handle that just fine. (Seems it can handle 15 amps total) So your 15 amp fuses will be fine and you don't really need the 10 gauge wire. It's really stiff and can be a bear to work with.
Well the diagram's a bit bigger than I was planning on, but at least you can see it. Attach the 14 gauge wire to a positive volt source, doesn't have to be at the fuse box, you're using a separate fuse. Put your fuse in the line close to the source though. Use the switch, to ground the coil on the relay. Hook 30 and 85 to the battery, 87 to the lights and 86 to the switch. When you close the switch, the coil energizes, closes the relay and on go the lights.

 

[MUDONTHETIRES]

Mike,

I'll try that. Thanks for the great graph!

 

[POC]

Sorry to dredge this up.....but do you really need the relay? Can't you just run it straight through the switch?
Thanks,
Patrick

 

[mjncad]

POC: Sorry to dredge this up.....but do you really need the relay? Can't you just run it straight through the switch?
Thanks,
Patrick

Patrick:

Assuming the switch is rated for the current the lights draw; yes you can run it through the switch. However, automotive industry practice is to run heavy loads through a relay. Be safe and use the relay, they aren't that much hassle to use.

Mike058:
Re: ?'s About Wiring Work Lights On A Mahindra
If my math is right, two 55 watt lights (110 watts total) draw about 8 amps at 13.8 volts. The 14 gauge wire should handle that just fine. (Seems it can handle 15 amps total) So your 15 amp fuses will be fine and you don't really need the 10 gauge wire. It's really stiff and can be a bear to work with. Attachment 98945
Well the diagram's a bit bigger than I was planning on, but at least you can see it. Attach the 14 gauge wire to a positive volt source, doesn't have to be at the fuse box, you're using a separate fuse. Put your fuse in the line close to the source though. Use the switch, to ground the coil on the relay. Hook 30 and 85 to the battery, 87 to the lights and 86 to the switch. When you close the switch, the coil energizes, closes the relay and on go the lights.

Mike:

It would be better if your control switch was on the hot side of the circuit upstream of the relay instead of downstream as your wiring diagram depicts. Even though the switch will work as drawn, you still have juice running into the relay. In this case, you want the switch to de-energize everything downstream of the switch.

Mud: The wire coming from terminal 30 of the relay goes to the battery.
Where should the wire coming from the switch going to a "fuse panel" go if you don't have a fuse panel? At least I don't think I have a fuse panel. Please pardon me as I'm not very "electrically literate". Kennyd, you would be a great help here! I have supplied the wiring diagram for my tractor in pdf format below for reference if anyone has any ideas!

I've seen worse wiring diagrams than Mahindra's that you supplied; but I'm sure it has a fuse panel in spite of Mahindra showing each fuse separately, thus implying that each circuit has it's own inline fuse holder. I think Jeep used to use inline fuses many decades ago; but fortunately quit that silly practice. More than likely the fuse panel is behind the instrument cluster or hopefully it's like it is on my Deere....easily accessible via a removable cover below the steering wheel near the floor mat. Mahindra is showing the fuse as a rectangle with the text "10A," "15A," etc in it. That's how I was taught to draw fuses many years ago, and I still do to this day.

Matt

 

[snafukelly]

Can someone explain to me why that is not a short circuit in mike058's diagram?
Is the wire from 30 to 85 not creating a short circuit.
Someone please explain.

Thank you.

 

[Danno1]

.

No, it's not.

He's applying 12vdc through the fuse to the coil of the relay at term 85. Closing the switch in the lower center of the pic energizes the relay coil which closes the switch inside the relay. This sw needs 12vdc to turn the lights on. It gets that 12vdc from term 30.

.

 

[kennyd]

Can someone explain to me why that is not a short circuit in mike058's diagram?
Is the wire from 30 to 85 not creating a short circuit.
Someone please explain.

Thank you.

No short, it's just the battery + feed to the coil of the relay and to one side of the contact.

 

[Mike058]

Mike:

It would be better if your control switch was on the hot side of the circuit upstream of the relay instead of downstream as your wiring diagram depicts. Even though the switch will work as drawn, you still have juice running into the relay. In this case, you want the switch to de-energize everything downstream of the switch.

If I put the switch on 85, I'd have to run a 12 volt line to the switch and then down to the relay. By putting the switch on 86, I have to run one wire to the relay and find a ground for the other. I've found it's usually easier to find a ground point than a 12 volt source. I don't see any advantage to having the switch between the battery and the relay. When the switch is open, no current flows anywhere in that line regardless of what side of the relay it's on. If the switch isn't between the battery and the relay and I'm going to work on the relay, I can remove the fuse. But, the important point is, like you said, it will work either way. If you can sneak 12 volts from something else in the dash, run it to the switch and then down to 85. If that can't work. run a wire from 86 up to the switch and ground the other side. The other thing is to use the relay to keep the heavy wires short. Decreases voltage drop and saves money on expensive heavy gauge wire.

 

[mjncad]

If I put the switch on 85, I'd have to run a 12 volt line to the switch and then down to the relay. By putting the switch on 86, I have to run one wire to the relay and find a ground for the other. I've found it's usually easier to find a ground point than a 12 volt source. I don't see any advantage to having the switch between the battery and the relay. When the switch is open, no current flows anywhere in that line regardless of what side of the relay it's on. If the switch isn't between the battery and the relay and I'm going to work on the relay, I can remove the fuse. But, the important point is, like you said, it will work either way. If you can sneak 12 volts from something else in the dash, run it to the switch and then down to 85. If that can't work. run a wire from 86 up to the switch and ground the other side. The other thing is to use the relay to keep the heavy wires short. Decreases voltage drop and saves money on expensive heavy gauge wire.

I understand your points Mike; but look at any automotive or house wiring diagram, and the switch is always between the source of electricity and the load. You would have to use a lot of heavy gauge wire to make a big difference dollar wise and the voltage drop is not going to be as bad as you might think, especially when using the proper gauge wire for the load.