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Chapter 3
Safety
This chapter was written by James N.
Woods, W7PUP, and includes additional
contributors as well. This chapter will
focus on how to avoid potential hazards as
we explore Amateur Radio and its many
facets. We need to learn as much as pos-
sible about what could
go wrong
so we can
avoid factors that might result in acci-
dents. Amateur Radio activities are not in-
herently hazardous, but like many things
in modern life, it pays to be informed.
Stated another way, while we long to be
creative and innovative, there is still the
need to act responsibly. Safety begins with
our attitude. Make it a habit to plan work
carefully. Don’t be the one to say, “I didn’t
think it could happen to me.”
Having a good attitude about safety is
not enough, however. We must be knowl-
edgeable about common safety guidelines
and follow them faithfully. Safety guide-
lines cannot possibly cover all situations,
but if we approach each task with a mea-
sure of common sense, we should be able
to work safely.
This chapter will address some of the
most popular ham radio activities: build-
ing and erecting antennas, constructing
radio equipment, and the testing and
troubleshooting of our radios. Safety as-
sociated with emergency disaster opera-
tions are covered best by the agencies and
organizations affected.
Although the RF, ac and dc voltages in
most amateur stations pose a potentially
grave threat to life and limb, common sense
and knowledge of good safety practices
will help us avoid accidents. Building and
operating an Amateur Radio station can be,
and is for almost all amateurs, a perfectly
safe pastime. Carelessness can lead to
severe injury, or even death, however. The
ideas presented here are only guidelines; it
would be impossible to cover all safety
precautions.
Remember: There is no sub-
stitute for common sense.
Fires in well-designed electronic equip-
ment are not common but are known to
occur. Proper use of a suitable fire extin-
guisher can make the difference between a
small fire with limited damage and loss of
an entire home. Make sure you know the
limitations of your extinguisher and the
importance of reporting the fire to your
local fire department immediately.
Several types of extinguishers are suit-
able for electrical fires. The multipurpose
dry chemical or “ABC” type units are rela-
tively inexpensive and contain a solid pow-
der that is nonconductive. Avoid buying the
smallest size; a 5-pound capacity will meet
most requirements in the home. ABC ex-
tinguishers are also the best choice for
kitchen fires (the most common location of
home fires). One disadvantage of this type
is the residue left behind that might cause
corrosion in electrical connectors. Another
type of fire extinguisher suitable for ener-
gized electrical equipment is the carbon
dioxide unit. CO
2
extinguishers require the
user to be much closer to the fire, are heavy
and difficult to handle, and are relatively
expensive. For obvious reasons, water ex-
tinguishers are not suitable for fires in or
near electronic equipment.
Involve your family in Amateur Radio.
Having other people close by is always
beneficial in the event that you need im-
mediate assistance. Take the valuable step
of showing family members how to turn
off the electrical power to your equipment
safely. Additionally, cardiopulmonary re-
suscitation (CPR) training can save lives
in the event of electrical shock. Classes
are offered in most communities. Take the
time to plan with your family members
exactly what action should be taken in the
event of an emergency, such as electrical
shock, equipment fire or power outage.
Practice your plan!
Antenna and Tower Safety
Since antennas are generally outdoors,
they are affected by such potentially haz-
ardous weather as wind, ice and lightning.
Learning about the potential hazards of
towers and antennas and how to do
antenna work safely will pay dividends.
ARRL Technical Advisor Paul Krugh,
N2NS, reminds us to remember that put-
ting up a tower has a set of responsibilities
associated with it.
Any heavy, large and
permanent structure that fails or collapses
can potentially hurt or even kill somebody.
The complete installation
must
comply
with all applicable structural and building
codes. Professional engineers design
towers to withstand code loadings — that
is, dead weight, wind and ice loadings that
are applicable to the environment at your
particular location. The latest revision of
the EIA-222 standard is the document
from which professional engineers work
to ensure that their tower designs are struc-
turally safe. For further information, con-
tact the Electronic Industries Alliance
(EIA) in Arlington, CA.
To ensure structural safety and integ-
rity, you must demonstrate that your tower
has been designed by a qualified engineer
to withstand EIA-222 loadings at your
specific geographic area. Further, the
tower, foundation, guys and anchors must
be installed (and maintained) according to
any drawings, instructions and specifica-
tions supplied by the professional engi-
neer. Remember: A properly designed,
installed and maintained tower should be
Safety
3.1
as safe as a building or a bridge!
It is not feasible to discuss each type of
antenna and tower in detail, so this section
will include only highlights. For a full
understanding of the specific hardware
you will be working with, consult the
manufacturer or supplier. You should dis-
cuss your antenna plans with a qualified
engineer. The ARRL Volunteer Consult-
ing Engineer program can steer you to a
knowledgeable engineer.
In addition, your town or city will prob-
ably require that you obtain a building
permit to erect a tower or antenna. This is
their way to help ensure that the installa-
tion follows good practices and that the
installation is safe. Wise amateurs realize
that an independent review of drawings
and site inspections are beneficial and can
result in fewer problems in the future.
Towers must have a properly engineered
support, both for the tower sections them-
selves as well as guy wire attachments.
Sometimes towers are braced to buildings
for added support. The Antenna Supports
chapter of
The ARRL Antenna Book
covers
this subject in greater detail. Towers are
available commercially in both guyed and
self-supporting styles, and constructed of
both steel and aluminum materials. Masts
may be wood or metal. One popular and
inexpensive mast used to support small
antennas is the tubular mast often sold for
TV antenna use. These come in telescoping
sections, in heights from 20 to 50 ft.
Aluminum extension ladders are some-
times used for temporary antenna sup-
ports, such as at Field Day sites. One
problem with this approach is the diffi-
culty in holding down the bottom section
while “walking up” the ladder. Do
not
try
to erect this type of support alone.
Trees are sometimes pressed into ser-
vice for holding one end of a wire antenna.
When using slingshots or arrows to string
up the antenna, be sure no one is in range
before you launch.
FACTORS TO CONSIDER WHEN
SELECTING A TOWER
•
Towers have design load limitations.
Make very sure the tower you consider
has the capacity to safely handle the
antenna(s) you intend to install in the
kind of environment that is applicable
to your QTH.
•
The antenna must be located in such a
position that
it cannot possibly tangle
with power lines, both during normal
operation or if the structure should fall.
•
Sufficient yard space must be available
to position a guyed tower properly. A
rule of thumb is that the guy anchors
should be between 60% and 80% of the
tower height in distance from the base
3.2
Chapter 3
of the tower.
•
Provisions must be made to keep chil-
dren from climbing the support.
•
Always write to the manufacturer of the
tower before purchasing and ask for in-
stallation specifications, including guy-
ing data.
•
Soil conditions at the tower site should
be investigated. The footings need to be
designed around actual soil conditions,
particularly on a rocky site.
TOWER TIPS
•
Beware of used towers. Have them pro-
fessionally inspected and contact the
manufacturer for installation criteria.
•
Always follow manufacturer’s instruc-
tions, using only parts that are designed
for the model you have.
•
Never rush into projects. Consult the
most experienced amateurs in your
community for assistance, especially if
you are new to tower installation.
•
Check with your local building officials.
•
Liability may be increased with a tower
installation. Check with your insurer to
ensure your coverage is adequate.
•
Consider your neighbors about any haz-
ards your antennas may present to them.
•
Don’t let your installation become an
“attractive nuisance.” Take steps to in-
stall barriers so your tower cannot eas-
ily be climbed by others, particularly
adventurous children.
•
Use only the highest quality materials
in your system.
•
Make sure you have all the tools needed
before starting. Some specialized tools
(such as a gin pole) may be required.
•
Never erect an antenna, tower or rotor
during an electrical storm or rainstorm,
or when lightning is a possibility.
•
The assembly crew as well as those
climbing the tower during erection must
wear hard hats and use appropriate per-
sonal protective equipment including
gloves, boots, climbing belt or harness.
Don’t forget that lifelines are needed
when the belt is unattached from the
tower while moving.
•
Be careful not to over-stress the tower
when it is being assembled. The tower
manufacturer can offer suggestions that
will avoid jeopardizing the tower.
•
Install guy wires using the proper tools.
Care should be exercised especially when
handling loose, un-terminated, and sharp
guy wire ends! Avoid wrapping guy wire
around your hands to pull it into place,
and instead use sufficient length to easily
attach it to the anchors. Use tower-rated
turnbuckles or similar devices to adjust
tension evenly around the tower.
• Assign someone in the erection crew to
monitor the use of safety equipment.
• After the tower is installed, keep the
installation safe. Inspection and main-
tenance recommended by the tower’s
manufacturer should be carefully fol-
lowed.
•
If making attachments to houses or in-
stallations on roofs, have a qualified
person determine that the method is ade-
quate and the loading conditions are sat-
isfactory.
•
Avoid metal ladders if there are any util-
ity lines in the vicinity. Assume that any
line is energized — including cable tele-
vision and telephone lines.
POWER LINES
Hundreds of people have been killed or
seriously injured when attempting to in-
stall or dismantle antennas. In virtually all
cases, the victim was aware of the haz-
ards, including the potential for serious
electrical shock, but did not take the nec-
essary steps to eliminate the risks. Never
install antennas, towers and masts near
power lines. How far away is considered
safe? Towers and masts should be in-
stalled twice the height of the installation
away from power lines. Every electrical
wire must be considered dangerous. If the
installation should contact power lines,
you or those around you could be killed! If
you have any questions about power lines,
contact your electrical utility, city inspec-
tor or a qualified professional.
If, for some reason your tower or antenna
structure begins to fall, get away from it
immediately! If it contacts energized lines,
it can become a lethal hazard if you are
touching any part of the conductive struc-
ture. If a coworker becomes energized,
do
not touch the person!
The safest practice
is to keep all others clear of the area, call
911, and just wait for the power company
and rescue team to arrive and assist the vic-
tim. At some greater risk, a well-insulated
pole such as fiberglass or PVC pipe — as
long as possible for safety — can be uti-
lized in an attempt to dislodge the live wire
or collapsed metal structure from the vic-
tim (with moisture, etc., wood can be a
poor
insulator
— especially at high voltages!).
If the victim can be well cleared of the haz-
ard and is not breathing, immediately start
CPR procedures and seek emergency as-
sistance.
Remember, use caution and un-
derstand that during such an accident,
the live conductor or live antenna struc-
ture can further move (lurch) suddenly
and without warning. One accident is
bad enough — there is no need to have
two victims! It is best to just seek quali-
fied emergency help if you are unsure of
the situation-specific hazards.
Further information about tower safety
appears in
The ARRL Antenna Book.
Electrical Wiring Around the Shack
The standard power available from
commercial mains in the United States for
residential service is 120/240-V ac. The
“primary” voltages that feed transformers
in our neighborhoods may range from
2000 to about 10,000 V. Generally, the
responsibility for maintaining the power
distribution system belongs to a utility
company, electric cooperative or city. The
“ownership” of conductors usually trans-
fers from the electric utility supplier to the
homeowner where the power connects to
the meter or weatherhead. If you are
unsure where the division of responsibil-
ity falls in your community, a call to your
electrical utility will provide the answer.
Fig 3.1
shows the typical division of re-
sponsibility between the utility company
and the homeowner.
There are two facets to success with
electrical power: safety and performance.
Since we are not professionals, we need to
pursue safety first and consult profession-
als for alternative solutions if performance
is unacceptable.
STATION CONCERNS
The primary electrical power supplied
to your radio equipment should be con-
trolled by one master switch so that it is
easy to kill the power in an emergency.
One convenient means is a switched outlet
strip, as used for computer equipment. The
strip should be listed by a nationally rec-
ognized testing laboratory such as Under-
writers Lab and incorporate a circuit
breaker. See “What Does UL Listing
Mean?” and “How Safe are Outlet Strips?”
for warnings about poor quality products.
It is poor practice to “daisy-chain” several
power strips. If you need more outlets than
are available on a strip, have additional
convenience outlets installed.
Before adding equipment to your home,
be sure that it does not overload the circuit.
National and local codes set permissible
branch capacities according to a rather
complex process. Here’s a safe rule of
thumb: consider adding a new circuit if the
total load is more than 80% of the circuit
breaker or fuse rating. (This assumes that
the fuse or breaker is correct. If you have
any doubts, have an electrician check it.)
Do It Yourself Wiring?
Amateurs sometimes “rewire” parts of
their homes to accommodate their hobby.
Most local codes
do
allow for modifica-
tion of wiring (by building owners), so
long as the electrical codes are met. Gen-
erally, the building owner must obtain an
electrical permit before beginning changes
or additions to permanent wiring. Some
Fig 3.1 — Typical division of responsibility for maintenance of electrical power
conductors and equipment. The meter is supplied by the utility company.
What Does UL Listing
Mean?
CAUTION: Listing
does not
mean what most consumers
expect it to mean! More often than
not the listing
does not
relate to
the performance of the listed
product. The listing simply indi-
cates that a sample of the device
meets certain manufacturers’
construction criteria. Similar
devices from the same or different
manufacturers may differ signifi-
cantly in overall construction and
performance even though all are
investigated and listed against the
same UL product category
Fig 3.2 — If the switch box feeding
power to your shack is equipped with a
lock-out hole, use it. With a lock
through the hole on the box, the power
cannot be accidentally turned back on.
(Photo courtesy of American ED-CO)
jobs may require drawings of planned
work. Often the permit fee pays for an in-
spector to review the work. Considering
the risk of injury or fire if critical mistakes
are left uncorrected, a permit and inspec-
tion are well worth the effort.
Don’t take
chances
— seek assistance from the build-
ing officials or an experienced electrician
if you have
any
questions or doubts about
proper wiring techniques.
Ordinary 120-V circuits are the most
common source of fatal electrical acci-
dents.
Never use bare wire for exposed
circuits or open-chassis construction with
exposed connections! Remember that
high-current, low-voltage power sources
can be just as dangerous as high-voltage
sources.
Never work on electrical wiring with the
conductors energized!
Switch off the cir-
cuit breaker or remove the fuse and take
positive steps to ensure that others do not
restore the power while you are working.
(Fig
3.2
illustrates one way to ensure that
power will be off until you want it turned
on.) Check the circuit with an ac voltmeter
to be sure that it is “dead”
each time you
begin work.
Before restoring power, check
your work with an ohm meter: There should
be good continuity between the neutral
conductor (white wire, “silver” screw) and
the grounding conductor (green or bare
wire, green screw). An ohmmeter should
indicate a closed circuit between the con-
ductors.
There should be no continuity between
the hot conductor (black wire, “brass”
screw) and the grounding conductor or the
neutral conductor. An ohmmeter should
indicate an
open
circuit between the hot
wire and either of the other two conduc-
tors.
Safety
3.3
A commercially available plug-in tester
is the best way to test regular three-wire
receptacles.
NATIONAL ELECTRICAL CODE
Fortunately, much has been learned
about how to harness electrical energy
safely. This collective experience has
been codified into the
National Electrical
Code,
or
NEC.
The
Code
details safety re-
quirements for many kinds of electrical in-
stallations. Compliance with the
NEC
provides an installation that is
essentially
free from hazard, but not necessarily effi-
cient, convenient or adequate for good
service (paraphrased from NEC Article
90-1a and b). For example, the
NEC
re-
quirements discussed here are
not
ade-
quate for lightning protection and high
transient voltage events. Look at “Light-
ning/Transient Protection” for more infor-
mation. While the
NEC
is national in
nature and sees wide application, it is not
universal.
Local building authorities set the codes
for their area of jurisdiction. They often
incorporate the
NEC
in some form, while
considering local issues. For example,
Washington State specifically exempts
telephone, telegraph, radio and television
wires and equipment from conformance
to electrical codes, rules and regulations.
However, some local jurisdictions (city,
county and so on) do impose a higher level
of installation criteria, including some of
the requirements exempted by the state.
Code interpretation is a complex sub-
ject, and untrained individuals should
steer clear of the
NEC
itself. The
NEC
is
not written to be understood by do-it-
yourselfers. Therefore, the best sources of
information about code compliance and
acceptable practices are local building
officials, engineers and practicing electri-
cians. With that said, let’s look at a few
NEC
requirements for radio installations.
Antenna conductors —
Transmitting
antennas using hard-drawn copper wire:
#14 for unsupported spans less than
150 ft, and #10 for longer spans. Copper-
clad steel, bronze or other high-strength
conductors must be #14 for spans less
than 150 ft and #12 for longer spans.
Open-wire transmission line conductors
must be at least as large as those speci-
fied for antennas.
Lead-ins —
There are several
NEC
requirements for antenna lead-in conduc-
tors. For transmitting stations, their size
must be equal to or greater than that of the
antenna. Lead-ins attached to buildings
must be firmly mounted at least 3 inches
clear of the surface of the building on non-
absorbent insulators. Lead-in conductors
must enter through rigid, noncombustible,
3.4
Chapter 3
nonabsorbent insulating tubes or bush-
ings, through an opening provided for the
purpose that provides a clearance of at
least 2 inches; or through a drilled win-
dowpane. All lead-in conductors to trans-
mitting equipment must be arranged so
that accidental contact is difficult.
Lightning arrestors —
Transmitting sta-
tions are required to have a means of drain-
ing static charges from the antenna system.
An antenna discharge unit (lightning arres-
tor) must be installed on each lead-in con-
ductor that is not protected by a permanently
and effectively grounded metallic shield,
unless the antenna itself is permanently and
effectively grounded. (The code exception
for shielded lead-ins does
not
apply to coax,
but to shields such as thin-wall conduit.
Coaxial braid is neither “adequate” nor
“effectively grounded” for lightning pro-
tection purposes.) An acceptable alternative
to lightning arrestor installation is a switch
(capable of withstanding many kilovolts)
that connects the lead-in to ground when the
transmitter is not in use.
Ground Conductors
Grounding conductors may be made
from copper, aluminum, copper-clad steel,
bronze or similar erosion-resistant materi-
als. Insulation is not required.
[Lightning
and high-voltage transient events may
require much larger conductors. —Ed.]
The “protective grounding conductor”
(main conductor running to the ground rod)
must be as large as the antenna lead-in, but
not smaller than #10. The “operating
grounding conductor” (to bond equipment
chassis together) must be at least #14. There
is a “unified” grounding electrode require-
Fig 3.3 — At A, proper bonding of all grounds to electrical service panel.
Installation shown at B is unsafe — the separate grounds are not bonded. This
could result in a serious accident or electrical fire.
ment — it is necessary to bond
all
ground
rods to the electric service entrance ground.
All utilities, antennas and any separate
grounding rods used must be bonded to-
gether.
Fig 3.3
shows correct (A) and
incorrect (B) ways to bond ground rods.
Fig
3.4
demonstrates the importance of cor-
rectly bonding ground rods. (Note: The
NEC
requirements do not address effective
RF grounds. See the
EMI/Direction Find-
ing
chapter of this book for information
about RF grounding practices.)
Additionally, the
Code
covers some
information on safety inside the station.
How Safe are Outlet Strips?
CAUTION: The switch in outlet strips is generally
not
rated for repetitive
load break
duty. Early failure and fire hazard may result from using these
devices to switch loads. Misapplications are common (another bit of bad
technique that has evolved from the use of personal computers), and
manufacturers are all too willing to accommodate the market with marginal
products that are “cheap.”
Nonindicating and poorly designed surge protection also add to the safety
hazard of using power strips. Marginally rated MOVs often fail in a manner
that could cause a fire hazard, especially in outlet strips that have nonmetal-
lic enclosures.
A lockable disconnect switch or circuit breaker, as shown in Fig 3.2, is a
better and safer station master switch.
All conductors inside the building must be
at least 4 inches away from conductors of
any lighting or signaling circuit except
when they are separated from other con-
ductors by conduit or insulator. Transmit-
ters must be enclosed in metal cabinets,
and the cabinets must be grounded. All
metal handles and controls accessible by
the operator must be grounded. Access
doors must be fitted with interlocks that
will automatically disconnect all voltages
above 350 when the door is opened.
Ground-Fault Circuit Interrupters
GFCIs are devices that can be used with
common 120-V circuits to reduce the
chance of electrocution when the path of
current flow leaves the branch circuit (say,
through a person’s body to another branch
or ground). The
NEC
requires GFCI outlets
in all wet or potentially wet locations, such
as: bathrooms, kitchens, and any outdoor
outlet with ground-level access, garages
and unfinished basements. Any area with
bare concrete floors or concrete masonry
walls should be GFCI equipped. GFCIs are
available as portable units, duplex outlets
and as individual circuit breakers. Some
early units may have been sensitive to RF
radiation but this problem appears to have
been solved. Ham radio shacks in poten-
tially wet areas (basements, out buildings)
should be GFCI equipped.
Fig 3.5
is a sim-
plified diagram of a GFCI.
LIGHTNING/TRANSIENT
PROTECTION
Nearly everyone recognizes the need to
protect themselves from lightning. From
miles away, the sight and sound of light-
ning boldly illustrates its destructive
potential. Many people don’t realize that
destructive transients from lightning and
other events can reach electronic equip-
ment from many sources, such as outside
antennas, power, telephone and cable TV
installations. Many hams don’t realize that
the standard protection scheme of several
decades, a ground rod and simple “light-
ning arrestor” is
not
adequate.
Lightning and transient high-voltage
protection follows a familiar communi-
cations scenario: identify the unwanted
signal, isolate it and dissipate it. The dif-
ference here is that the unwanted signal is
many megavolts at possibly 200,000 A.
What can we do?
Hams
cannot
expect to design or install
effective lightning protection systems, but
reasonably complete protection from
lightning is available in systems designed
by lightning protection professionals.
Hams
can
easily follow some general
guidelines that will protect their stations
against high-voltage events that are in-
Safety
3.5
Fig 3.4 — These drawings show the importance of properly bonded ground rods.
In the system shown in A, the 20-A breaker will not trip. In the system in B, the
20-A circuit breaker trips instantly. There is an equipment internal short to ground
— the ground rod is properly bonded back to the power system ground. Of
course, the main protection should be in a circuit ground wire in the equipment
power cord itself!

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