At work, I recently put in a ground system for our new translator, which requires a good ground system. A critical part of that is properly bonding the copper ground wires to the ground rod. The best way to do that is exothermic welding.

A lot of people call it CADweld, which is a registered trademark of Erico, which is one source. However their less expensive One Shot has been difficult to acquire. In searching the internet, I found a different company that makes the same thing. They call it a Uni-Shot, made by Harger and can be found at tessco.com.

 Using this method of bonding ground wires to your ground rods, prevents corrosion, and high resistance connections to your ground rods. If you use a clamp, or other compression method to bond your ground system, it will require cleaning the connections regularly, and still won't insure a good ground connection.

In this blog post, I will show you how to use a CADweld uni-shot to exothermically weld your ground rods. The photo below shows all of the components of the CADweld uni-shot.

How to Bond Ground Rods with Cadweld uni-shot exothermic weld

 From left to right, you have the following items:

 1. Uni-Shot Mold
 2.Ceramic Disk
 3. Metal Disk
 4. Starting Powder
 5. Ceramic Lid

Steps to bonding a ground rod:

1. This step is very important. Do not skip this step, or your exothermic weld will not take. Buff the ground rod, and the ends of each copper wire to be attached to the ground rod with steel wool. Sometimes if the ground rod is too corroded, its easier to take a hack saw and cut of the top inch of the ground rod.

2. Roll the mold on to the ground rod. Its important to roll it on, and not just slide it on. This keeps the rubber seal in good shape.

3. Place the copper grounding wire into the holes on the side of the uni-shot mold. The end of the copper wire needs to be over the center of the ground rod. The photo below is looking down from the top of the mold:

 

How to bond ground rods with Cadweld exothermic weld