Properly grounding my mast

protivakid · 25-Sep-2013, 5:02 PM

I have a 2ft J shaped mast holding up my small antenna on the highest point of my house. There are many trees taller than this antenna around my house but want to properly ground. I had rigged up what I thought was a proper way to ground the small mast but want to correct my setup.

I read the info from http://www.starkelectronic.com/cmig8.htm and have some questions. I have two ground rods that are inside my basement along the wall where the electricity & cable comes in. My antenna is on the roof ~30 ft above these ground rods.

I have some bare #8 aluminum wire that I planned on running from the mast, down the side of the house, inside the house, and down to the grounding rod. I was then going to use another short piece of #8 aluminum wire and run it from a coax grounding block outside of the house, to the inside of the house, and down to the grounding rod again.

Does this setup make sense or am I horribly off? Also I know copper is better than aluminum but the site I referenced above says to use either and I already have the aluminum. Will it make a huge difference to use copper wire instead? If so what type of wire should I use and where is the best place to get it?

GroundUrMast · 25-Sep-2013, 6:48 PM

You'll need to take steps to protect the aluminum from damage and corrosion. That requires the use of connectors rated for use with aluminum. It's amazing how quickly aluminum can corrode into white powder when in contact with a dissimilar metal, concrete or soil. What may appear solid and secure is actually insulated by the aluminum oxide that may be a few thousands of an inch thick. You also need to coat the connectors and the wire in the connectors with an anti-oxidizing paste. Frankly, I avoid the problem by using copper exclusively.

Copper is a better conductor so you can use the next smaller trade size, #10 AWG. If you need to pass through a wall near the ground, use conduit and/or insulated wire to protect the wire from contact with concrete, conduit, plumbing, etc.

I prefer to avoid leading the mast or coax ground into the building. You may be able to avoid that in your case if you can connect the ground leads to the exterior of the meter base or metal conduit that enters or exits the base. There are several ground clamp options to choose from, ex. http://www.cesco.com/resources/78378...achmentURL.pdf - http://www.tnb.com/ps/fulltilt/index.cgi?part=J2D - http://www.electricmotioncompany.com...?type=ibonding

You can almost always find the wire and connectors in the electrical department of the big box home centers.

protivakid · 25-Sep-2013, 7:19 PM

So grounding the antenna mast to the meter base will work just as well? I would also prefer to keep from running the mast ground into my home.

Would this work clamp wise for the mast?

http://www.ebay.com/itm/380434965011...84.m1439.l2649

GroundUrMast · 25-Sep-2013, 10:05 PM

The NEC code provides the option to use the meter base, service panel and conduit (raceway) in addition to the ground rod(s).

I prefer to go directly to ground... But I also like to avoid leading fault current into my house.

The clamp looks like it's the right type, but double check your mast diameter. Many J-poles are a bit larger than 1 1/4".

protivakid · 26-Sep-2013, 2:07 PM

Thanks I'll check the pipe diameter. As far as meter box clamps I am having trouble finding quantities for sale less than 10 but does this look like it will do the job?

http://www.ebay.com/itm/Electric-Mot...item4ac9794ae9

GroundUrMast · 26-Sep-2013, 8:14 PM

Quote:

Originally Posted by protivakid

Thanks I'll check the pipe diameter. As far as meter box clamps I am having trouble finding quantities for sale less than 10 but does this look like it will do the job?

http://www.ebay.com/itm/Electric-Mot...item4ac9794ae9

'BINGO!'... Yes, that looks great, provided there's a lip on you meter base that that clamp can grip.