Whether it's the PC in our Wireless Access Truck, a massive 1000W amplifier or an extra power plug for a cell phone, the same rules apply... ignore 'em, and you could turn your car into a fire hazard... or just blow out its electrical system.
It's been raining sideways for the better part of a week here in San Francisco, and none of us own a garage, so progress on the Wireless Access Truck is moving a bit slower than we'd like.
But we've had lots of time to think about wiring up that puppy, and Patrick is looking to correct a laundry list of wiring issues for the accessories in his vehicle.
He's especially inspired by NASA's collection of Workmanship Standards, which includes the most excellent NASA WORKMANSHIP STANDARDS PICTORIAL REFERENCE, where you can see how rocket scientists properly crimp a terminal, and a whole lot more... a great reference!
Safely wiring your vehicle (especially if you have, say, 400W worth of lights or a massive 500W amplifier) is about choosing a heavy enough gauge, or size, of wire, and figuring out how far it has to travel from your battery.
The longer the distance, the lower the gauge wire you need for a given load... with wire gauges, the smaller then number the amperage it can carry.
To figure out the appropriate gauge wire, you'll use a gauge/distance table of some sort... we've used The12volt.com's chart, Recommended Power and Ground Cable Sizes along with RBE Electronics WIRE GAUGE SELECTION TABLE and PowerStream's Wire Gauge and Current Limits.
They all offer the same basic idea: chart the electrical load in Amps or Watts, go to the column for the distance, and you'll get a recommended gauge wire for the run. (We tend to go a size up 'cause we're paranoid, and, hey, you never know when you might want to add another gadget.)
Your car should be running a 12V system... to figure out that Amperage load from a device that lists its power consumption in Watts, divide the number of Watts by 12V. (For more on this, check out Episode 18: Obey The Laws (Of Power)
Patrick got all that burly wiring hardware from VTE... not just because he's looking to deal with 40A worth of lighting on the front of his truck, along with almost 80A worth of amplifiers... but because the prices are super cheap compared to the usual bling bling car audio stuff. The ANL Fuse Block was definitely a bit bigger than he expected, but the price was super cheap for an
Just don't skip putting a fuse in there!