On 1/15/2015 8:35 PM, donovanf@starpower.net wrote:
NEC quotes relevant to this discussion:
How things change. When "we" installed an underground service, in our
area 3 ground rods were required, but they are in triangle
"more-or-less" and only 3 feet apart. This was roughly 10 to 15 years
ago. All are tied together with a single ground wire back to the
common point at the entrance panel. So all ground systems tie to that
commom point
Note: I don't know the size, but those ground rods appear to be 8' and
no more than 5/16ths, or maybe 3/8ths inch.
Although I hear, "don't do it" the shortest route from the station SPG
is a direct line, under the house to the common point in the main
panel. It was that compared to nearly a 100' run around the house.
Typical rise time would allow a much higher voltage differential in the
station by going around Vs going through.
Twice I have "dug up" the rods and both times the clamps were loose.
The one time I replaced them. I've been tempted to replace them with a
current setup and larger ground rods. I thought the mechanical
connections were not to be buried, but I don't know the requirements
back then. I "assume" it was OK as the installation was hooked up be
the power company and inspected by the local inspector.
Since then we have "picked up an inspector" who worked as a union
electrician. "Rumor-has-it" according to a number of people in the area
it's difficult to get him to OK anything that was not done by a licensed
electrician even if it is perfect.
73
Roger (K8RI)
Not less than two driven ground rods placed at a minimum of 6 feet
apart when a non-metallic water piping system exists or is to be installed.
A separate grounding conductor to each ground rod shall be utilized
The grounding electrode conductor shall be solid or stranded , sized in
accordance with the requirements of the NEC but shall in no case be less
than No. 6 AWG copper or No. 4 AWG aluminum or copper-clad aluminum.
All ground rods will be required to be minimum 1/2" x 8' copper weld or
5/8” x 8’ copper plated only.
No galvanized rods or piping will be accepted as a grounding electrode.
73
Frank
W3LPL
----- Original Message -----
From: "Donald W. Kane via RFI" <rfi@contesting.com>
To: eedwards@oppd.com, rfi@contesting.com
Sent: Friday, January 16, 2015 1:23:03 AM
Subject: Re: [RFI] w7ekb & ground rods
NEC requires minimum 6 ft. between ground electrodes..for better
performance minimum 2X electrode length (e.g. 16 ft for 8 ft rods).
73
Don
WB2BEZ
In a message dated 1/15/2015 4:46:00 P.M. Eastern Standard Time,
eedwards@oppd.com writes:
Excellent point Jim. All services' grounds (AC, telephone, television,
internet and ham shack cable entry point & ham tower) must be bonded to a
single-point ground system. There's no limit on number of ground rods as long
as they're bonded (i.e. tied to the same grounding system). 8 foot ground
rods need to be within 16 ft of each other, but can be closer if needed to
shorten cable run to each service ground connection.
Couple more good references for grounding and bonding standards from
Motorola & Harris:
http://www.radioandtrunking.com/downloads/motorola/R56_2005_manual.pdf
http://www.repeater-builder.com/ge/lbi-library/t4618r3a.pdf
73, de ed -K0iL
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