Satalite Ground Connection (810.21(e)) Question

jamiedolan · 02-20-2009, 04:31 PM

Goodafternoon,

I need to get my satellite dish grounded. (just delt with my parrents a couple weeks ago, there ground is droping to a fairly close ground rod already connected to there se with 6awg) I've read the code, and understand the allowable bonding points.

810.21(e) is my concern;

"(E) Run in Straight Line. The grounding conductor for an
antenna mast or antenna discharge unit shall be run in as
straight a line as practicable from the mast or discharge unit
to the grounding electrode."

The closest bonding point would be my water meter (with 5' of entrance), which will be about a 50' run with about four 90degree turns.

My dish is not high, it is about 6 feet off the ground mounted on the attached garage. So the risk of a lightning hit is likely fairly low.

Do you think this run to the water meter would be effective?

My only other option is to drive a rod for the dish and use around 90' of 6awg through the house to bond the rod to my other rods.

Thanks
Jamie

wirenut1110 · 02-20-2009, 04:45 PM

You can do the rod and then go to your water pipe. Within 5' of where it enters. You don't have to go to the ground rods.

jamiedolan · 02-20-2009, 06:55 PM

Quote:

Originally Posted by wirenut1110

You can do the rod and then go to your water pipe. Within 5' of where it enters. You don't have to go to the ground rods.

Thanks, so would this fall under 250.54 and that is why it can run to the water pipe instead of bonding to the other rods?

Do I still use 6awg to the water meter, or would 10awg be acceptable in this case?
Thanks
Jamie

wirenut1110 · 02-20-2009, 07:06 PM

810.21(F)(2) 1-6, whichever is closest/easiest and yes use #6

Billy_Bob · 02-21-2009, 07:02 AM

Code aside, be sure to bond all grounds together. This prevents "ground loops" which electronic things don't like and which can cause electrical "noise".

Water meters can use rubber grommets which electrically isolate the pipes on both sides of the meter. So good to install pipe clamps on both sides of the meter and a wire bonding jumper.

Then sometimes plastic PVC is run for water pipes or metal water pipe is replaced with plastic. So if using the water meter as a ground, be sure there is metal pipe all the way to the house and this metal pipe is also bonded to your electrical system ground rods.

Then all your grounding will be bonded together (satellite antenna as well as satellite receiver in house via house electrical system).

The satellite antenna uses a coax cable which has a metal braid. This metal braid typically connects to the metal on the dish via the "LNB" as well as to the ground on the satellite receiver. And if the two grounds are at a different "potential" (not bonded), then you can get a ground loop current running through that coax braid.

Then the bigger the grounding wire the better, but this also costs a fortune, so do what you can.

If this is a paid satellite TV antenna, then the grounding is not very critical as these satellite signals are quite strong. But if something like free-to-air MPEG satellite, then some of these satellites are quite weak and this would be quite important.

Ground loop problems...
http://www.epanorama.net/documents/groundloop/

FYI - free-to-air satellite...
http://www.google.com/search?hl=en&q...Search&aq=f&oq=