Short-Circuit Iron Fires
It’s practically impossible to operate modern equipment without the use of black-box devices that run off a tractor, combine, or sprayer’s 12-volt system. Be warned: There is a right and wrong way to connect such devices to a vehicle’s electrical power. Doing it the wrong way could result in the equipment catching fire in the field or, worse, in storage where the entire shed could burn down.
To their credit, manufacturers have recognized the need for a safe and convenient source of auxiliary power in cabs and, as such, have provided properly switched and overload-protected outlets within the cab.
Some outlets are backed up with 30-amp fuses, which is more than enough power to run any device. Those same outlets are arranged so you can have a choice between switched power (on with the key only) and full-time power. Each of those two selections has its own particular advantages.
Never Hook Directly to a Battery
What you never want to do is connect any device directly to the battery group in the tractor.
Yes, I know that some devices might come with long power leads that suggest doing that. This is never an option, however, and here is the reason.
The tiny wiring that feeds power to a device is nowhere near capable of taking full battery current in the event that a wire becomes pinched or otherwise shorted to ground. When the very high amperage from the battery group is brought to bear on those little wires, it will easily melt, burning them away if you are fortunate or causing a fire in the cab if you aren’t quite so lucky.
When making power connections in a cab, you should be visualizing the overall power system of the vehicle, making absolutely certain that if you do connect to the battery group, there is always a low-amperage fuse located between the battery and any power leads. That low-amperage fuse should always be set very close to where the power is taken off the battery group. Having a fuse holder sitting on top of the battery group is a good way to provide a safe connection, but it might not be the most convenient place to have a fuse when you are trying to find an electrical glitch.
You should also keep two things in mind when plugging a device into a factory-provided outlet in a cab.
First, if you run short of places in the cab to plug into, you can get a splitter from the dealer that makes it possible to use one outlet to provide power to more than one device.
Second, remember that factory outlets are usually backed up by very heavy fuses. If the device you are connecting has a very low amp draw, it’s a good idea to insert the fuse holder that came with the device into the wire that is located close to the factory plug. The smaller fuse will properly protect the device, and it will be in a convenient location should you ever need to check on it.