House ground layouts
House Ground Layouts
Common Mode Current (some practicality to
lightning and safety
lightning and safety
and entrance wiring
RF In Station
Equipment (mostly RF related)
antenna random wire (RF related)
small 160 meter
antenna (RF related)
radiation resistance (RF related)
Corrections to confusing text made on July 21,
Ham Radio and Communications Grounding Solutions
People claim there isn’t anything that can be done to
prevent lighting damage. This is often used as an excuse to do nothing at all,
other than a complete disconnect during storms. While nothing is 100% certain,
installations near 100% are quite possible with a little work and care.
Since 1998, my station has been connected with some equipment active 24 hours a
day, every day of the year. I have several towers between 50 feet and 318-ft
tall, with taller towers being struck in nearly every significant local
thunderstorm. I also have miles of wire and cables in receiving arrays, spread
out over 100 acres.
My station never has significant lightning damage inside
buildings to consumer electronics, modems, security systems, or radio gear.
Damage has been confined to outdoor antennas and hardware.
Even a modest ground system, when things are done
correctly and carefully, will greatly increase lighting immunity. An abundance
of commercial grounding specifications exist, but they are either too costly or
physically impossible to install in a residential hobby installation. Hams (amateur radio operators) and CB
radio operators almost always cannot have ideal
grounds, but with care and planning very safe systems can be installed for
Trouble spots are usually caused by not following simple rules.
Poor but Commonly Used
The most severe and frequent damage is normally not caused by a voltage
difference between each conductor in a multiple wire cable, but from those
conductor groups or bundles to other conductor groups or bundles. Nearly all severe lightning damage is caused by
lightning currents flowing through the house wiring as common mode current.
This first example has severe ground loops. It is a danger for many reasons. It does
not protect for
power line neutral faults, equipment failures, or lightning.
With a system like this, we should plan on damage when lighting strikes
anywhere near electrical power lines or antennas.
Drawing on Left
This system is the most common type of wiring used by Hams and
CB’ers. It has a tower ground rod or rods, an equipment ground rod or water pipe
connection, and an entrance panel ground at the electric meter. It does not comply with national
electrical and fire codes, because it is independent entrance grounds.
The dashed line from the
electrical service entrance panel
to the radio room represents the power line leads in the house.
The heavier solid line represents all control and feed line cables from the
This is a very poor setup. Lightning protection, regardless of quality entrance
protection devices that might be installed, will be almost nonexistent. Common mode lightning currents,
the worse kind, will simply loop through equipment to the powerline. This is
true if lightning strikes on or near power, CATV, or Telco lines, or if lightning strikes
on or near your antenna system.
Better but Not Perfect
This system adds a wide, heavy connection (shown as a thick black line
outside house) between the entrance grounds. This connection could go under the
house. My bonding connection, for example, goes directly under my house in the
crawl space. I use 3-4 inch wide copper flashing with no splices or bends under
the house. My bonding connection is kept away from other metallic objects like
plumbing, ductwork, and wiring, even though it routes right under the house.
This bonding connection significantly reduces chances of damage from power line neutral
faults and lightning strikes on the power lines or your antennas. This system meets
national fire protection suggestions. (Although it is much better than the
common isolated ground installations, lightning
protection can still be improved.)
The nearer the radio room entrance panel and ground is to the electrical
service entrance ground, and the lower bonding
conductor resistance and impedance is compared to the impedance and distance of
mains wiring to the radio in the house, the better this system will work!
(Remember lightning has considerable higher frequency energy, treat it like RF.)
The dashed line from the entrance panel to the desk again represents
all of the power and telephone lines.
The lighter solid line represents feed line and control
lines. It goes through a grounded entrance panel.
The heaviest line is the bonding conductor.
Any desk ground wire should route parallel and near the operating desk to
feed line and control wire bundle entrance panel to the feed line entrance panel.
Do NOT run the desk ground directly to the station ground rod.
Remember while this is much better and meets codes, it is still not the best configuration.
A portion of common mode lightning currents will still flow through equipment to
the mains ground unless the radio equipment is unplugged or disconnected from
all cables and grounds going to the entrance panel, or both.
Better For Gear but Bonding Missing
This is another system that significantly improves protection of the equipment at the operating
desk. Unfortunately it omits the critical ground bonding necessary for full house protection.
It does NOT meet national code requirements. The mains ground is not
bonded to the station entrance ground.
EVERYTHING on the desk or connected to the operating desk in the radio room
has to routed from the room common point entrance to the desk. No exceptions!
The three lines from the panel to the desk are all of the power lines, a line
representing all of the control lines and antenna cables, and the ground wire.
These lines can and should be bundled or closely spaced if possible.
The problem? While it forms a protection zone in the radio room, the path for
common mode lightning currents between the antennas and the power lines is
through house wiring! This can cause a large voltage difference between
electrical wires and other metallic conductors throughout the house.
Best by Far
This system meets all codes. This system is nearly as good as bringing all
antenna system cables and wiring in at the house utility
entrance (which would be perfect).
EVERYTHING on the desk or connected to the operating desk in the radio room
has to run from the room common point entrance. No exceptions!
The closer the radio room cable entrance is to the power mains entrance, the
more effective this system is.
The two lines from the radio room entrance ground panel to the desk include all power lines,
with the medium size solid line
representing a bundle of all control wires, all antenna cables and any desk grounding
wire. These lines should be bundled or closely spaced.
Everything entering the desk area, including Telco and power connections, must be routed from the radio room entrance panel common
The value of the optional tower-to-station bonding conductor connection
(longer dashed line) depends on distances. If the tower or antenna is near the
house, it is better to bond it in. If the tower if more than 50 feet away, it
might as well be isolated on its own ground because the impedance will likely be
too high to be an effective bond.
The system to the left is my basic system. Pictures are shown below.
Desk Equipment Grounding
In the old days, desktop radio equipment needed a ground. This is because we
did not have three wire plugs with safety grounds, and because gear used high
voltages. Without a three-wire cord safety ground, there was a risk of 120 volts
appearing on the chassis from power line wiring and component shorts. Even
worse, a short between a power transformer primary and secondary could put
thousands of volts on the equipment case!
Sometime around the 1960’s, equipment and wiring started changing. Outlets
added a third round pin. That pin connected back to the breaker panel case, and
electrical system ground. Equipment started using a three wire cord with a
permanent chassis ground, or was double insulated. Control wires also changed
from 120 VAC (run directly from power mains) to low voltage 12-24 volt control
wires. These changes worked to eliminate the need for a desk ground on modern
A second issue is RF desk
grounding. In early days, we didn’t have resources to explain balance and
common mode RF currents. Long wire and Windom antennas were more common. While
we still have equipment improperly manufactured, largely because of design
errors in the book Baluns and UnUn’s or lack of good cabinet integrity, most
problems have gone away. For the most part, unless we have something wrong,
there is no need for a desk RF ground.
Four common manufacturing defects causing RFI and making a desk hot with RF
- Use of a single-core 4:1 current balun. This
described by Sevik in “Baluns and UNUN’s”, and has found its way into
several commercial products. This balun forces systems into gross unbalance.
Some commercial tuners and commercial baluns used this very flawed design.
- Use of insulated or isolated areas of enclosures. One very expensive
tuner actually intentionally insulated the cabinet cover, supposedly to
reduce eddy currents. Insulating the cover does not reduce eddy currents at
all, and causes the cover to be “hot” with RF.
- Use of marginal ground or “no-ground” Marconi antennas. Such
“no radial” antennas
promote common mode on feed lines, making cable shields and cabinets of
- Use of
end-fed halfwave antennas. End-fed antennas promote common mode on
feed lines, making cable shields and cabinets of equipment radiate.
Another misconception or myth is that
filters divert harmonics and
unwanted RF to ground. Filters on coaxial lines do NOT need to be grounded
to block harmonics. Filters on power lines or balanced lines should be grounded
to the equipment chassis, but not to earth ground.
One thing is very important. ALL equipment on the desk should be operated
with the same cabinet potential. We want the RF transmitting shield connections
between desktop gear to be as low as possible. This means we NEVER
want RF isolators on desktop transmitting RF cables. It is good salesmanship or
product marketing to tell people to install transmitting cable line isolators on
the desk, but it is terrible scientific advice.
This is my house station entrance.
All control cables are shielded.
All shields are grounded.
The house is surrounded by a halo ground.
All desk power is grounded to station ground buss.
This is my “wire hider” built to look like a window seat. A finished cover
fits over it.
All cables feed out from here in a bundle to the desk.
Just outside the rear wall is my outside grounding point. All cables
enter through a 4 inch corrugated pipe.
Under desk. All equipment on desk feeds from common outlets, and all wiring is parallel
Without my “wire hider” I would have many dozens of cables feeding the desk
instead of only several cables. The wire hider was the single best thing I ever
did to clean up my desk wiring.
The only grounds running up to desk gear go to my old “unsafe” boatanchor
Picture January 2010.
All this equipment runs from only several cables entering the desk area. With
just a few cables I have the selection of almost 30 receive antennas, dozens of
transmitting antennas, and five amplifiers (1500 watts from one sixty through
In addition the flip of a few switches and moving two or three
multi-conductor plugs to new sockets transfers all antennas to my contesting
Not only does lightning protection improve, station wiring is much more
The Globe Scout was the first commercial transmitter I ever owned. It was
bought used from WRL and arrived via Railway Express at Central Union Terminal
in Toledo, Ohio. It was a gift for passing my General. Prior to that all of my
gear was home brew, including my receivers. See my