TROOPER
10-12-2008, 05:07 PM
Grounding How and Why
Grounding your equipment is something that many people often overlook either from ignorance or being in a hurry. Proper grounding is one of the most important things in a satellite or any other electrical installation. Your installation is not complete unless it is grounded.
Technically “grounding” is referred to as “bonding” as you are attaching to a pre existing ground in most cases rather than creating a ground source. For purposes of this document “bonding” is referred to as “grounding”.
Why Ground?
1. Prevents and discharges static buildup on dish. Static charge can interfere with your signal and damage your LNB, switch & STB. Have you ever noticed your signal/quality go down before a storm and stay low after it has passed and cleared? This is usually static charge on the dish causing this.
2. Longer switch life and reliable operation. Static charge can interfere with switching commands and shorten switch life.
3. Lightning protection. Grounding will not save your equipment from a direct lightning strike but it can help to protect your TV, DVD and household wiring from damage by providing a partial path for current to discharge.
4. NEC requirement for all outdoor antennas (dishes) and electrical equipment. (USA)
5. Off air signal interference. This can be reduced/eliminated by proper grounding.
How and what to ground
Every component in the system should be grounded. This includes the LNB, dish, cables, switches and enclosures if applicable.
LNB’s are grounded by grounding both the dish and the RG-6 coaxial cable. Both single and duel RG-6 is available with #17 messenger wire attached. This is a 17 gauge solid copper wire that is molded into the outside of the cable shielding. If you do not use this type wire NEC requires you to run a separate 10 gauge copper or 8 gauge aluminum wire from the dish to the grounding block.
http://i38.tinypic.com/eitg6b.jpg
The dish is grounded by hooking up the messenger wire or the #10 copper wire to a metal point on the dish or mast. Most masts have a hole where a green ground screw goes, this is the ground point. If you do not have this you can use a nut/bolt on the back of the reflector to attach your wire(s). If using a metal in ground pole mount it does not hurt to drill a hole and hook up a ground wire. The pole itself does not constitute a legal ground.
All grounds should run to a grounding block or multiswitch that is designed with a ground spot. This grounding block ideally should be within 20 feet of the actual ground point, that is the grounding rod or house ground.
http://i33.tinypic.com/2r3yyp3.jpg
Run a #10 or bigger copper wire from the ground block to your ground source. Try to avoid sharp bends in the ground wire. High voltages can arc across tight turns/bends. Use wire that is shielded if possible rather than bare wire.
Acceptable grounds
1. Ground rod. This is a copper clad rod either 4, 5 or 8 feet long that is driven into the ground. A clamp goes at the top to attach your grounding wires. A ground rod should already exist as part of your household electrical system. Search around the electrical entry point of the home for it
http://i34.tinypic.com/15gfd02.jpg
2. Electrical meter. This is the meter outside of your house. There are clamps that will allow you to attach a wire to the corner of a meter box. You can also get ground clamps that will attach to conduit coming from the meter. (Metal conduit only.) Clean the attaching surface before applying the clamp.
3. Grounded water pipe. Ideally this should be a metal pipe within 20 feet of the ground source. Clean the area before applying the clamp. There are different types of clamps for different types of metals, this is to prevent corrosion caused by junctions of dissimilar metals.
In some applications you can drive a new ground rod for use with your equipment. There is a small risk of creating a ground loop by doing this. A ground loop is created when the potential difference between the household ground and the new ground rod is high. Current can actually flow thru your coaxial cable out of the house into your dish & switches. In extreme cases you can receive a dangerous shock from equipment that is in a ground loop. This is a very rare occurance and can be checked for with a multimeter by measuring voltage between the household ground and the grounding rod you installed.
Grounding your equipment is something that many people often overlook either from ignorance or being in a hurry. Proper grounding is one of the most important things in a satellite or any other electrical installation. Your installation is not complete unless it is grounded.
Technically “grounding” is referred to as “bonding” as you are attaching to a pre existing ground in most cases rather than creating a ground source. For purposes of this document “bonding” is referred to as “grounding”.
Why Ground?
1. Prevents and discharges static buildup on dish. Static charge can interfere with your signal and damage your LNB, switch & STB. Have you ever noticed your signal/quality go down before a storm and stay low after it has passed and cleared? This is usually static charge on the dish causing this.
2. Longer switch life and reliable operation. Static charge can interfere with switching commands and shorten switch life.
3. Lightning protection. Grounding will not save your equipment from a direct lightning strike but it can help to protect your TV, DVD and household wiring from damage by providing a partial path for current to discharge.
4. NEC requirement for all outdoor antennas (dishes) and electrical equipment. (USA)
5. Off air signal interference. This can be reduced/eliminated by proper grounding.
How and what to ground
Every component in the system should be grounded. This includes the LNB, dish, cables, switches and enclosures if applicable.
LNB’s are grounded by grounding both the dish and the RG-6 coaxial cable. Both single and duel RG-6 is available with #17 messenger wire attached. This is a 17 gauge solid copper wire that is molded into the outside of the cable shielding. If you do not use this type wire NEC requires you to run a separate 10 gauge copper or 8 gauge aluminum wire from the dish to the grounding block.
http://i38.tinypic.com/eitg6b.jpg
The dish is grounded by hooking up the messenger wire or the #10 copper wire to a metal point on the dish or mast. Most masts have a hole where a green ground screw goes, this is the ground point. If you do not have this you can use a nut/bolt on the back of the reflector to attach your wire(s). If using a metal in ground pole mount it does not hurt to drill a hole and hook up a ground wire. The pole itself does not constitute a legal ground.
All grounds should run to a grounding block or multiswitch that is designed with a ground spot. This grounding block ideally should be within 20 feet of the actual ground point, that is the grounding rod or house ground.
http://i33.tinypic.com/2r3yyp3.jpg
Run a #10 or bigger copper wire from the ground block to your ground source. Try to avoid sharp bends in the ground wire. High voltages can arc across tight turns/bends. Use wire that is shielded if possible rather than bare wire.
Acceptable grounds
1. Ground rod. This is a copper clad rod either 4, 5 or 8 feet long that is driven into the ground. A clamp goes at the top to attach your grounding wires. A ground rod should already exist as part of your household electrical system. Search around the electrical entry point of the home for it
http://i34.tinypic.com/15gfd02.jpg
2. Electrical meter. This is the meter outside of your house. There are clamps that will allow you to attach a wire to the corner of a meter box. You can also get ground clamps that will attach to conduit coming from the meter. (Metal conduit only.) Clean the attaching surface before applying the clamp.
3. Grounded water pipe. Ideally this should be a metal pipe within 20 feet of the ground source. Clean the area before applying the clamp. There are different types of clamps for different types of metals, this is to prevent corrosion caused by junctions of dissimilar metals.
In some applications you can drive a new ground rod for use with your equipment. There is a small risk of creating a ground loop by doing this. A ground loop is created when the potential difference between the household ground and the new ground rod is high. Current can actually flow thru your coaxial cable out of the house into your dish & switches. In extreme cases you can receive a dangerous shock from equipment that is in a ground loop. This is a very rare occurance and can be checked for with a multimeter by measuring voltage between the household ground and the grounding rod you installed.