About once every three months or so, I tend to run an article like this. I’ve called grounding “the most important thing you’re not doing” and I stand by that. Even some professional installers don’t do a good job of grounding equipment, and in the end it’s up to you. You need to make sure that your home is protected. If you’re not the homeowner, you need to make sure the homeowner is protecting you.
What is grounding?
Grounding is a simple idea. When the air gets charged with electricity (as it does in a lightning storm), eventually that electricity has to go somewhere. We see the result of this all the time as lightning. Lightning is the air discharging its electricity and literally putting that electricity into the ground.
Electricity is like water in that it’s going to go the easiest possible way. Whatever the closest and most effective possible thing is, if that thing conducts electricity well, the electricity will flow into it. Often times that thing is at the top of a building. Sometimes it’s your TV antenna or satellite dish.
If lightning is going to strike your home, you want somewhere for the electricity to go. Electricity isn’t smart. It’s going to go the easiest possible path, as I said. So, we run a nice copper wire down into the ground for the electricity to follow. This is called “grounding.”
What equipment needs grounding?
Any piece of metal on top of your home needs to be grounded. Luckily the process is easy. You run a ground wire from that piece of metal to something connected to the actual ground. Often times you’ll see a green screw on that roof-mounted thing, that’s where the ground wire goes. If you’re grounding a cable you usually use a ground block. The cable passes through that and you attach a ground wire to it. Some antennas and dishes will be fully grounded if the cable is grounded and some will not. You should definitely consult any owner’s manual for proper grounding of anything you put on your roof.
How should you connect the ground wire?
This is really up to your local city hall. Many cities, towns, and counties allow you to run a ground wire to a cold water pipe. An iron cold water pipe that goes underground takes the place of a ground wire quite effectively. In many cases you can run the ground wire to the backplane of your circuit breaker box (some people call it a “buzz box.”) That’s for largely the same reason, because the breaker box has its own ground connection. It better have, anyway, or you have other issues.
The most important thing here is that you follow local ordinances. A local electrician or your city clerk can clear things up for you.
Is it necessary to ground indoor equipment?
If the you see a green screw on the equipment, you should ground it or bond it. (Bonding means attaching a ground wire to the building’s master grounding system.) If it has a three-prong plug, it’s going to bond itself through the electrical plug into your house ground. If it has neither of those things, don’t try to ground it. Some home theater equipment does not need grounding. In these cases the ground terminal (the round prong on a 3-prong outlet) can allow for an audible buzz if there is stray RF signal on the ground line. This happens a lot actually. If you see a device with a two-prong plug and you think it needs a three-prong one, don’t try to ground it.
Will proper grounding prevent damage?
Here’s the real answer: proper grounding might not prevent 100% of damage if lightning strikes your home. A lightning bolt is very powerful and a skinny little wire is probably not going to contain 100% of the electricity. There could be a power surge that knocks out some of your really sensitive electronics, and some of the electrical lines themselves might overload. However, lightning will cause far less damage to a properly grounded home compared to if the home’s grounding system wasn’t there at all.
What’s the best place to get grounding supplies?
Your local hardware store or industrial supply house will have a lot of grounding equipment. Honestly you are really better off going to SolidSignal.com for your grounding needs. Why? Because we have all the right parts to ground audiovisual equipment and antennas. There’s no guarantee that your local person is going to have the right stuff or even know what the right stuff is.