This section is going to explore how an electrical ground works, why grounding our satellite system is so important, and what represents a properly grounded installation.
The NEC defines grounding as:
A source intentionally connected to the earth through a ground connection, or connections of sufficiently low impedance and having sufficient current carrying capacity to prevent the build-up of voltages that may result in undue hazard to connected equipment or persons .
Reasons to Ground Each System
Electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilize the voltage to earth during normal operation.
The intent of the grounding provisions of the NEC is to ensure that electrical systems are as safe as possible to the individuals that use them.
Lightning & Surge
For electricity to flow, it has to have a complete circle or circuit.
The ground connection to Earth gives the excessive electricity or over current conditions a quick path away from equipment and the people inside the house and allows it to dissipate through the earth.
By the time the surge gets in the ground and travels a bit, it loses much of its strength and becomes harmless.
This does not guarantee complete protection from lightening / surge damage or injury. As it states, it reduces the likelihood of such damage or injury.
Static can build up on the dish like it builds up in you when you walk across a carpet.
When the static electricity build-up exceeds what the antenna can store, it discharges wherever it can.
If this static gets to the receiver or LNBF, it could damage internal electronic components.
A common symptom of this is a temporary interruption of signal which leads to a call from the customer requesting a technician to correct the problem.
Radio Frequency Interference (RFI)
Radio Frequency Interference (RFI) occurs when stray RF signals are picked up by the cables and, if not grounded, can find their way onto a customer’s TV.
This can cause a disturbance or distortion of the satellite signal.
Without a proper ground, the wires outside the house work like a big coat hanger antenna.
Identify the acceptable grounding locations in the diagram.
Acceptable Grounding Locations
1. A properly installed grounding rod. This is the grounding electrode system.
2. A grounded interior metal water pipe within 5 ft from the point of entrance into the building and in contact with soil. No external water pipes should be used !
3. The exterior of a main power service entry enclosure.
4. The power service metal conduit (sometimes called a “metallic raceway”).
5. Steel structure of a mobile home frame.
The bonding must be separate – it cannot share the same clamp
with telephone or cable companies.
Grounding Block Installation
The following EchoStar installation standards must be followed:
Ground blocks are always mounted vertically with connectors facing left and right. This helps prevent water from dripping directly into the connector.
Ground the dish antenna and all cables.
Only one wire is to be used per lug screw on the ground block. Do not stack wires.
Grounding Block Installation (Pg 2)
Use 10AWG ground wire from the ground block(s) to the ground source.
17AWG copper glad steel may be used between the dish and ground block.
Ensure the distance from the ground block(s) to the ground source is not more than 20 feet.
A grounding block is acceptable for DNS installation if it is stamped with a UL label and have blue plastic in the ports.
The messenger ground wire is an NEC-approved 17AWG ground wire molded into the jacket of the coaxial cable to simplify the grounding of the satellite dish. The messenger cable eliminates the need to run a separate wire from the dish to ground. When using the messenger wire to ground, wrapping the ground wire through the drip loops minimizes the grounding effectiveness and violates NEC code.
Ground Lugs / Ground Screws
When grounding the mast, the green ground screw is to be used in the small holes in the side of the mast footplate.
If a pole mount is used, the hole for the green screw must be predrilled with a 11/64” drill bit and the ground screw is to be installed on the base of the skew plate.
When using a 1000.2 dish, one of the 3 holes at the top of the skew plate can be used.
Multiple Dish Grounding
When grounding multiple dishes, there are two available options depending on where the dishes are.
If the dishes are within 10 feet of each other:
The 10AWG wire can be run from a ground lug/screw on the footplate to another ground lug/screw on the other footplate. Then using a separate ground lug/screw use the 17AWG messenger wire to the ground block.
Do not stack the ground wires on the same ground lug/screw.
Multiple Dish Grounding (Pg 2)
If the dishes are located over 10 feet apart:
A separate messenger wire is run from each dish to a separate ground block.
These ground blocks are then bonded together by a piece of 10 AWG wire.
A separate piece of 10 AWG is connected from one of the ground blocks to the ground source.
Multiple Dish Grounding (Pg 3)
Connecting Multiple Ground Blocks
All wires coming down from the dish must be grounded. Sometimes the use of multiple ground blocks is required to accomplish this. Grounding multiple ground blocks is done following the same rules as grounding multiple dishes that are over 10 feet apart.
Remember to use a separate piece of 10 AWG from one ground block to the next.