What I Learned Today With Jeff Smith – Clean Power On Demand

It should be obvious why this clutter of connectors is not what you want. A single, large power wire coming off the battery will feed the separate terminal and remove this junk off the battery.

We quickly learned while working on older hot rods and muscle cars that a reliable source of switched 12-volt electrical power sounds good but frankly is often difficult to access. Most older cars usually offer only one switched 12-volt power connector on the fuse box and that is almost always taken by some accessory.

What is needed is an easily-accessed terminal block where you can connect to either 12-volt power directly from the battery or a switched 12-volt source. There are dozens of power strips on the market but they just didn’t fit our needs until we came across this simple dual-stud power terminal from Jegs.

This Jegs twin-post power terminal uses both ¼- and 3/16-inch posts. These two studs can be electrically tied together or used separately for access to both constant battery power and switched power. A relay can be used to provide the switched power.

This terminal has both 1/4- and 3/16-inch studs that can be used as separate power sources (switched and unswitched) or they can be easily joined together with a shunt. We like to mount a relay alongside this terminal and pull power directly from the battery with an inline 30-amp fuse to the larger ¼-inch stud which becomes straight battery power. We then feed switched power from the relay to the smaller 3/16-inch stud. Another feature of this Jegs terminal is that it comes with a snap-on cover that prevents accidental shorting across the terminals to ground. The terminal block is part number 555-10521

We’ve also mounted this terminal under the hood to give us easy access to electrical power without stacking a bunch of wires to the positive terminal of the battery. Nothing looks tackier than a stack of large cables stringing from the positive terminal of the battery. Plus, this terminal can be easily hidden near the battery using only one large wire feeding off the positive terminal. As an alternative to a stack of cables of a top terminal battery, consider a Group 34/78 battery that offers both top and side terminals to offer cleaner connections.

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About the author

Jeff Smith

Jeff Smith, a 35-year veteran of automotive journalism, comes to Power Automedia after serving as the senior technical editor at Car Craft magazine. An Iowa native, Smith served a variety of roles at Car Craft before moving to the senior editor role at Hot Rod and Chevy High Performance, and ultimately returning to Car Craft. An accomplished engine builder and technical expert, he will focus on the tech-heavy content that is the foundation of EngineLabs.
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