Ground Bars & Their Place in a Grounding System
A grounding system is a subset of your electrical system as a whole. It is comprised of several parts: A ground rod, wiring to connect the ground rod to a service panel or utility meter base grounding lug, and a ground bar. Its primary purpose is safety, with the goal being to have a path to dissipate a static discharge of voltage (such as lightening, for example) into the earth where it will be harmless.
The reason that a designated path is necessary is simply that without one, current seeks (And finds) its own path back to its voltage source, and of course, if left to its own devices, it will almost invariably pass through your expensive equipment. If this should happen, your equipment will either be badly damaged (best case) or outright destroyed (worst case).
Thus, the grounding system is important not only for safety, but also, it serves as cheap insurance. Simply by planning for the eventuality of a surge or static discharge and routing it appropriately, you can save yourself tons of time, money, and headaches down the road.
As a part of the system, the ground bar is a metal bracket (often copper, but any conductive metal will do), which serves as a central grounding point for equipment. If needs be, your power system manufacturer can create a custom ground bar to suit your specific needs.
The end point of the grounding system is the ground rod, which can be made from a variety of metals. The two most popular are copper and galvanized steel, specifically because their conductivity allows electricity to flow freely through them and away from your electrical panel. These rods are typically 8’ or longer in length, and can be anywhere from 3/8” to 1” thick.
The grounding rod is connected to the rest of the system using highly conductive wire, generally copper or aluminum, which is clamped in place to the rod using a grounding clamp. These are mechanical clamps that have set screws that tighten the clamp around the rod in order to form a solid connection. An acorn clamp is a fairly commonly used type of clamp for making ground rod connections and it is suitable for direct burial. An acorn clamp is an oval-shaped clamp that has a bolt, which is used to tighten it to the grounding rod. Alternately, there’s a brass-toothed clamp, a two-piece device that has a pair of setscrews, which are used to attach it to grounding rod. This type of clamp is most often used indoors to make grounding connections around water pipes.
Finally, there is the matter of welding. Most of the time, cad welds are utilized for industrial and commercial applications because they provide a secure grounding connection. This type of weld is accomplished by using a mold and a small amount of molding mixture. The mold is clamped to the ground rod, and a small disk is placed to hold the molding mixture in place until lit.
The mold mixture is inserted, the mold “cap” is lowered down into position, and the mold is lit. When this happens, the mixture ignites brilliantly, and the now-molten mixture begins to adhere to the rod, encompassing both the rod itself, and the ground wire. Once the mixture cools and the clamp is removed as it is no longer needed. If the weld is good and the connection is secure, you’re finished!
