Planning & Building Fences on the Farm

7/29/2019 Planning & Building Fences on the Farm

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Plann ing & Build ing

FENCESon the Farm

PB1541


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Contents

Pu rp ose of the Fen ce ...................................................................................................... 4Cattle.......................................................................................................................................................... 4

Sheep ......................................................................................................................................................... 4

Horses........................................................................................................................................................ 4

Swine ......................................................................................................................................................... 5

Plan nin g Th e Fen ce ........................................................................................................ 5Locatin g Permanent Fences.................................................................................................................... 5

Locating Temporary Fences ................................................................................................................... 5

Selecting Th e Proper Fen ce........................................................................................... 6Woven Wire Fences.................................................................................................................................. 6

Barbed Wire Fences ................................................................................................................................. 6

Board Fences............................................................................................................................................. 7

High-Tensile Fences................................................................................................................................. 7

Cable Fences ............................................................................................................................................. 7

Electric Fences .......................................................................................................................................... 9

Com paring Fences ................................................................................................................................... 9

Fencin g Materials and Eq uip men t ............................................................................ 10Fence Posts.............................................................................................................................................. 10

Wire .......................................................................................................................................................... 10

Stap les...................................................................................................................................................... 11Gates ........................................................................................................................................................ 11

Electric Fence Con trollers ..................................................................................................................... 11

Grounding .............................................................................................................................................. 12

Lightning Protection .............................................................................................................................. 12

Precau tion s ............................................................................................................................................. 13

Constru ction .................................................................................................................. 13Choosing the Fence Line....................................................................................................................... 13

Corner, End and Line Brace Assemblies ............................................................................................ 14

Setting Fence Posts ................................................................................................................................ 15

Runn ing Wire ......................................................................................................................................... 15

Tensioning Wire ..................................................................................................................................... 17

Repair an d Maintenan ce ............................................................................................. 17

References ...................................................................................................................... 18


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Planning and Build ing Fences

on the FarmMichael J. Buschermohle, Professor, Agricultural Engineering

James B. Wills, Professor, Agricultural and Biosystems Engineering

W. Warren Gill, Professor, Animal Science

Clyde D. Lane, Professor, Animal Science

Many innovations have occurred in the fenc-

ing indu stry in recent years, giving prod ucers an

array of options for fences to confine an d protect

livestock. Whether used as permanent, peripheryboundar ies, temporary pasture dividers or to

encircle a h ouse, fences need careful p lanning an d

construction for efficient usefulness, long life and

low maintenance.

Several decisions must be mad e when install-

ing fencing. First, what is the fence to be used for?

For example, is it going to be a bou nd ary fence or

a cross-fence to divide a pastu re? Is the fence for

sheep , cattle, horses or something else? What

type of fence is best suited and w here should the

fence be constructed for maximum effectiveness?

Other considerations includ e the typ e, spacing

and setting of posts, gate location and construc-

tion, brace post assembly and installation of stock

gaps or cattle guard s. This pu blication is de-

signed to help in planning a new or renovated

fencing system.

Purp ose of the Fence

The first considera tion in deciding th e best

fence is the pu rpose for wh ich it w ill be used.

Livestock p rotection and confinement ar e the

main reasons for considering fencing, but the

fencing needs for var ious types (species, age,

breed, p rodu ction system) of livestock vary

widely. Following are some of the livestock types

and situations with special requirements:

CattleMost types of fence can be u sed w ith cattle, so

most cattle producers assess factors such as

expense, ease of construction and exp ected life of

the fence when considering fencing strategy. Inthe past, woven w ire and barbed w ire were the

most common fence types; however,high-tensile

fencing is rapidly gaining popu larity in Tennes-

see. Fence height for perimeter cattle fences

should be a minimu m of 54 inches.

When bu lls are penned separately from cows,

special attention mu st be paid to construction.

Heavy posts with th ick-gauge w ire or cables are

requ ired, or electric fence may be effectively used .

Fences for hand ling facilities must be strong

enough to withstand heavy u sage, tall enough (60

inches minimu m) to prevent escape, and clearly

visible. Treated w ood or heavy w ire panel fences

are preferred.

SheepFences for sheep do n ot have to be as tall as for

cattle, but sheep have other special requirements.

Predator control is more imp ortant. Electric

fences are particularly useful for discouraging

pred ators such as dogs and coyotes. Barbed w ire

is not as effective with sheep , as the barbs tend to

become covered w ith wool.

HorsesVisibility is a necessary characteristic in fenc-

ing for horses. Barbed w ire shou ld be avoided

because there are m any opportu nities for horses to

tear their hide on the barbs. High-tensile wire

fences poses a threat to horses because they may

become entangled in the strand s. The chance of


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this can be decreased if high-tensile fences are

mad e m ore visible by p lacing posts closer to-

gether, or han ging ribbons or something else from

the wire. Board fences are ideal for horses. Wo-

ven w ire also works well, par ticularly with a

single board at the top so the horses can easily see

the fence.

SwineSwine requ ire strong fences that are bu ilt close

to the ground to p revent them from escaping by

rooting underneath the fence. Barbed w ire along

the ground helps prevent rooting. Fences need to

be no h igher than 54 inches.

As with cattle-working pens, fences aroun d

swine confinement units are likely to receive

heavy usage. Use heavy materials and sturdy

construction for long life and functionality.

Plann ing The Fence

Fencing is a costly investm ent. The location

and arrangem ent m ay affect p rodu ction efficiency,

so it makes good sense to plan before you bu ild.

This is true wh ether you are installing a fence

aroun d th e farm or a pasture for the first time, or

rep lacing an old, worn-ou t fence. Evaluate exist-

ing fences. If they are in good shape, you may

wan t to plan new fences aroun d them . If they are

old and falling d own , it may be cheaper in the

long run to rep lace them.

Pay attention to water resources wh en plan-

ning your fencearrangem ent. Wise placement of

fences can result in being able to use the same

water sou rce in tw o, three or even three or more

pastu res. Fencing cattle away from pond s and

using freeze-proof overflow tanks can imp rove

water qu ality and p revent disease problems

associated with cows standing in the pond s

du ring the sum mer. This also prevents injury and

death d ue to cattle breaking through frozen pond sin the winter. Plans and information about these

types of watering systems may be found at your

local Extension office or through the Soil Conser-

vation Service.

Locating Permanent Fences

Permanent fences should be well constructed

using h igh qua lity ma terials so they w ill last a

long time with minimu m repairs. A well-con-

structed perm anent fence that surrounds the farm

is essential. It establishes a fixed prop erty line

between you and your neighbors and prevents

losses du e to livestock getting killed on the high-

way or having to p ay your neighbors for livestock

dam age to their crops. Take care to prop erly

locate the property line wh en building bound aryfences to avoid costly mistakes.

Consider permanent fencing around pastures

wh ich w ill be used year after year and aroun d

cropland. These fences will probably never be

moved , so it makes sense to build a well-con-

structed, low m aintenance fence that will last a

long time. A perm anent fence is also a good idea

for a lane that g ives livestock access to water.

Locating Temporary FencesMovable fences are considered tempora ry

fences. They are normally used for a short period

of time, then removed and used in some other

location or stored u ntil needed . They are easy to

build and take dow n. They cost less than perm a-

nent fences, bu t they are not as effective and

usually w ill not last more than on e to three years.

They do not take th e place of perm anent fences,

but can be very ben eficial in some instances.

Temporary fences are well suited for con-

trolled grazing situations because p astures can be

divided into a substantial number of ind ividu al

cells w ith minimal labor an d cost. They can bemoved from year to year u ntil you decide the field

layout that best fits your p rodu ction scheme.

Locating Lanes an d GatesA lane is need ed to connect livestock bu ild-

ings, working facilities and wa ter with every field

that eventually may be pastured . Keep in mind

that a permanent pastu re located between other

fields can serve as a lane.

To keep gullies from forming on rolling land ,

plan the lane to followa terrace or natural ridge. If

a well-drained location is not possible, use mov-

able fences which can be relocated every few

years. Wherever possible, locate gates and p as-

sageways for livestock and equ ipment in the

corner of each field closest to farm buildings. If

you h ave fields on opposite sides of a road , locate

gates opp osite each other so livestock can go

directly across.


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Selecting The Proper Fence

There are many typ es of fences to meet vari-

ous fencing need s. Since fencing usu ally rep re-sents a rather large investment on most farms, it is

especially imp ortan t to select a fence that is

affordable, easy to maintain, durable and, most

importan tly, keeps livestock in. The kinds of

fences commonly u sed in Tennessee includ e

woven wire, barbed w ire, high-tensile, board,

electric or a combination of any of these.

Woven Wire Fences

Woven w ire fences consist of a nu mber of

horizontal lines of smooth wire held apart by

vertical wires called stays. The distance or spac-

ing between horizontal line wires may va ry from

as close as 1 1/ 2 inches at the bottom for small

animals, to as wide as 9 inches at the top for large

animals. In general, the spacing between w ires

gets wider as the fence gets taller.

Woven w ire is available in m any combinations

of wire sizes and spacings, as well as a number of

horizontal line w ires and fence heights. The

height of most w oven w ire fencing materials

ranges from 26 to 48 inches. The fence height

should be selected based u pon the animals sizeand their jum ping ability. Stay wires shoiuld be

spaced 6 inches apart for small animals and 12

inches for large an imals.

The stand ard d esign numbers listed on the tag

describe the wire. For

instance, a design num ber

1047-12-11 ind icates the

wire has 10 horizontal

wires and is 47 inches high,

stays are spaced 12 inches

apar t and stay-and-filler

wires (wires between the

top and bottom line wires)

are 11 gau ge wire. The top

and bottom w ires are

generally two sizes larger.

Stand ard w oven wire fence

sizes are show n in Table 1.

Barbed Wire FencesBarbed w ire fences are made of two or m ore

strands of smooth, galvanized-coated, steel wire

twisted together w ith two or four barbs spaced

every 4 to 5 inches. They are generally classified

as either a standard or suspension barbed wire

fence.

Stand ard barbed w ire fences usu ally have

three to five strands of barbed wire stretched

between p osts that are spaced betw een 15 to 25

feet apar t (Figure 1).

The suspension fence has 4 to 6 strands of

wire stretched taut so there is no more than 3

Design #

Horizontal

Wires Height (in .)

635 6 35

726 7 26

832 8 32

845 8 45

939 9 39

949 9 49

1047 10 47

1156 11 56

Table 1. Common Woven Wire Fencing Material

Figure 1. Common Spacings in Barbed Wire Fences


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High-tensile fences are constructed mostly

with 12 1/ 2 or 14 gauge Class 3 wires which have

tensile strengths from 170,000 to 200,000 or more

pound s per square inch (psi) and breaking

strengths of app roximetly 1,800 pou nd s (Figure 3).

This fence can w ithstand more than 1,100 pou nd s

of livestock pressure w ithout losing its elasticity,

yet it is flexible enough to bend, wrap , tie in knotsor clamp with crimping sleeves. Wires are held in

tension along wood, fiberglass, insulated metal

posts or a combination of posts and ba ttens or

drop pers. Tension in the wire is maintained by

perm anent in-line strainers. Adequ ate tension for

12 1/ 2 gauge high-tensile wire is 200 pound s. A

tension ind icator spring is used to indicate wire

tension.

High-tensile wire fences should be u sed w ith

electricity to improve animal-holding capability

and p redator control. It is importan t to use

treated w ood posts and set them p roperly in the

ground with adequate braces to withstand the

pressure caused by the tightly stretched wire.

Cable Fences

Because of their expense, cable fences are u sed

primar ily for confinemen t areas, such as hold ing

pens, feed lots and corrals. These fences usually

consist of 3/ 8-inch smooth steel wire cables

stretched betw een anchor posts. The cables are

norm ally mad e out of seven wires twisted to-

gether. Heavy du ty springs are placed at one end

of each cable to absorb the shock on the w ires

caused by animals pressing against them. Cables

are usually passed through h oles in wood en or

steel posts.

There is no limit as to the nu mber of cables

inches of sag between posts (Figure 2). Depen d-

ing up on the topograp hy, line posts are generally

spaced between 80 to 120 feet apart. The wires are

held ap art by tw isted w ire stays spaced 16 feet

apar t. Wind or anima ls hitting the fence cause it

to sway back and forth. This swaying motion

keeps animals away from th e fence and d iscour-

ages them from fighting through it. To allow the

fence to sway, the stays mu st not touch the

groun d or the effectiveness of the suspension

fence w ill be redu ced.

Board FencesBoard fences are very attractive, quite strong

and are safe for animals. They are typically used

as border fences around the farm or the home.Board fences consist of 1- to 2-inch thick, 4- to 6-

inch wide boards nailed to wood en posts spaced 8

to 10 feet apart. They can be built to any height ,

however, heights of 4 to 5 feet are m ost common.

The price of lum ber, nails, paint and other

materials along w ith the labor required makes the

cost of these fences considerably higher than most

perm anent w ire fences. Upkeep is also high,

especially if untreated lumber is used.

High -Tensile Fences

An increasingly p opu lar type of fence is high-

tensile wire fence. First used in New Zealand and

Australia, high-tensile wire fences offer several

advantages over conventional fencing:

easier to construct

last longer

cost less to build than m ost

conventional fences

require less maintenance

Figure 3. High-Tensile Fence

Figure 2. Suspension Barbed Wire Fence


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Table 2. Comparison of Common Fences


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that can be used ; how ever, a six-cable fence is

often u sed for large animals. The spacing be-

tween cables dep ends upon th e type of animals to

be confined .

Electric FencesElectric fences are widely and su ccessfully

used in Tennessee. They can be an effective, safeand inexpensive means of provid ing both temp o-

rary and p erman ent fencing if they are con-

structed p roperly and energized w ith a properly

sized controller.

Electric fencing does not need to be strong

because it seldom comes under pressure, but it

mu st be well designed and constructed to absorb

the imp act of anim als. It is also essential that

there is adequate pow er for the length of fencing

and the type of animals to be confined. Several

advan tages of electric fencing are low cost, inex-

pensive to operate, can be used to extend the life

of old perm anent fences or they can be used for

deer and pred ator control. They can be built for

temporary or permanent use.

Various typ es of inexpensive, easily-erected

temp orary electric fences are available. Probably

the most popu lar are the polywire strands or

ribbons which are fine w ires woven together with

polyethylene fibers.

Polywire comes in var ious colors. Black is the

most d ifficult for anim als and people to see.

Brighter colors, such as orange or wh ite, are alsoavailable. The polytape, particularly the extra-

wide type, is easier to see than polywire. This

type works better for horses. It is very imp ortant

to keep weeds and grass cut aw ay from the fence,

especially w hen u sing low impedance controllers.

If grass and weed s are allowed to touch most

polywires, the charge produ ced from low imped -

ance controllers can cause the small-diameter

wires to burn in tw o. Polywires with stainless

steel wires are m ore durable, but electric conduc-

tivity is lower. Alum inum cond ucts electricitybetter, but it breaks m ore easily.

Aluminu m, stainless steel and high-tensile

wire can also be used. One ad vantage to using

these type of wires is they cond uct electrical

charges for longer d istances than the small-

diameter w ires of the polywire and polytapes.

How ever, they are harder for the animal to see. To

effectively train animals to stay with in an electric

fence, the animals need to see the w ire as they feel

the shock. Tying pieces of white cloth or bright ly-

colored plastic ribbon w ill help m ake these w ires

more visible.

An electric fence controller is used to energ ize

the wire. The moist earth is used for completing

the electrical circuit. Corners and end posts in

tempora ry electric fences require m inimal bracing.

Line posts can be sm all and spaced far apar t since

the fence will generally be u sed for a short period

of time.

Comparin g FencesAs p reviously stated, when selecting a fence,

the things to consider a re what the fence is to beused for, how easy it is to build, w hat it costs to

build an d maintain and how long it is supposed

to last. Table 2 gives some general comp arisons

Post TypeBending

strength

Expected

life (yrs)

Initial

cost

Fire

resistanceMaintenance

Steel-T, concrete Fair 25-30 Medium Good Low

Steel rod 3/ 8" dia Poor 15-20 Low Good Medium

Heavy-duty fiberglass-T Fair (flexible) 25-30 H igh Poor Low

Light-d uty fiberglass-T Poor (flexible) 15-20 Low Poor Med ium

Pressure treated wood Good 30-35 Medium Poor Very Low

Untreated wood Good 7-15 Low Poor High

Table 3. Fence Post Characteristics


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Table 4. Life Expectancy of Wood Posts

Kind UntreatedTreated

(Pressure)

Treated

(Soak)

Osage O. 25-35 yrs - -

R. Cedar 15-25 yrs 20-25 yrs 20-25 yrs

B. Locust 15-25 yrs - -

W. Oak 5-10 yrs 20-30 yrs 15-30 yrs

Hickory 2-6 yrs 15-20 yrs 10-15 yrs

R. Oak 2-6 yrs 20-30 yrs 20-30 yrs

Y. Poplar 2-6 yrs 20-25 yrs 15-25 yrs

S. Gum 3-6 yrs 20-30 yrs 20-30 yrs

S. Pine 3-7 yrs 25-30 yrs 15-20 yrs

wire or h igh-tensile wire fence, the first step is to

choose good corner posts. Corner and gate posts

shou ld have a d iameter of at least 8 inches. Brace

posts should be 5 inches or more in d iameter.

Line p osts can be as small as 2 1/ 2 inches, but

larger diameter posts w ill make the fence stronger

and m ore durable.

Steel posts have several advan tages. They

weigh less, can be d riven into the ground rathereasily, wont rot and are fireproof. They also help

ground the fence against lightning when the soil is

wet. They aremore likely to be bent or forced ou t

of line by livestock. A wid ely used method is to

use w ooden line posts every 50 to 75 feet to help

keep steel posts from bend ing and imp rove the

strength of the fence.

All posts mu st be long enough to accomm o-

date the height of the fence and dep th of setting.

To get the correct fence post length , add together

the depth of setting, the height of the top w ire and

6 extra inches. Recomm ended post spacings for

various fences are show n in Table 5.

WireWire is covered with zinc, comm only called

galvan izing, to protect it from ru sting. The length

of time before fence wire begins to rust depend s

on the thickness of the galvanized coating . The

more ou nces of zinc per square foot of wire means

you can use to h elp select the type of fence that

best fits your need an d budget.

Fencing Materialsand

Equipment

Fence Posts

There are many typ es of posts available in

Tennessee (Table 3 ). Always try to find the best

post to meet the dem and s of the situation. For

example, it is best to u se good, treated posts for

perm anent peripheral fences, while light fiber-

glass or steel posts would be more suitable for

constructing temporary fences in a controlled

graz ing cell.

Often the least expensive option is to cut you r

own posts or purchase untreated, wooden posts.

They are highly variable in size, shap e and du ra-bility (Table 4 ). Osage orange posts have a

lifespan of 25 to 35 years, black locust or red cedar

posts w ill last for 15 to 25 years. Other wood s

such as oak, pine and pop lar will rot in just a few

years unless they are pressure treated.

Wood p osts come in an array of sizes and

lengths. The larger the top d iameter, the stronger

the post. Corners are the backbone of a fence.

Whether you plan to install a woven wire, barbed

Table 5. Recommended Post Spacings*

FenceSpacing

(feet)

Woven Wire 14 - 16

Barbed Wire 12 - 14

Suspension 100

Electric 40 - 75

High Tensile 40 -60

Board 8

Corrals 6

* Driven p osts are 1.7 times a s strong

as tamped p osts


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materials, including h eavy p ipes, railroad rails

and w ooden beams.

Electric Fence Con trollersMost producers will agree that touching an

electric fence is very unp leasant. The exper ience

for animals are no different. When an imals come

in contact with an electric fence, the shock they

receive affects their nervou s system. The severity,

or the amou nt of shock the animal feels, depend s

on the voltage and am perage as well as the dura -

tion of the shock. It takes a minim um shock of 700volts to effectively control short -haired breed s of

cattle, pigs and horses, and around 2000 volts for

long-haired cattle, sheep and goats. The controller,

often referred to as the charger or energizer, that

delivers th is shock is the hear t of any electric fence

and m ust be selected carefully. There are two

types of controllers currently on the m arket: high-

and low-imp edan ce controllers.

Electric fence controllers of year s ago, and

some brand s today, pu t out relatively high voltage

with low amperage. These are known as high-

impedance controllers. Because of their high

voltage and low current outp ut, there is no stay-

ing power of the charge. The first weed or blade

of grass to touch the fence will drain the power to

the extent that little or no shock is felt by the

anim al, after even a shor t distance of fencing.

Low-imp edance controllers have the capacity

to pow er long d istances of single or m ulti-wire

fence. These controllers pu t out a lower-voltage,

Climatic Conditions

Dry Humid

Class 1 Class 3 Class 1 Class 3

Wire Size Years u ntil ru st ap p ears on th e w ire

9 15 30 8 13

11 11 30 6 13

12 1/ 2 11 30 6 13

14 1/ 2 7 23 5 10

more years of service before rusting

starts (Table 6).

Fence manu facturers and the

American Society for Testing Mater i-

als have estab lished classes of zinc

coatings for fence wire. Class 1 has

the lightest coating of zinc and Class

3 has the heav iest. Because ofcompetition, many local fencing

supply dealers only stock wire w ith

Class 1 coating. Fencing ma terials

with Class 3 coating may h ave to be

specially ordered. Galvanizing

delays rusting. The more galvaniz-

ing on th e wire, the longer it w ill be

before rust starts to app ear.

Once steel wire starts to show

rust, it isnt long before the w hole

fence is ru sted. It usu ally takes from

one to three years from the time rust first app ears

un til all the wire is rusty. The durability of the

fence then depends on how fast rust weakens the

wire. Rusting slowly reduces the diameter of the

wire. As the diameter of the wire gets smaller, its

strength is redu ced.

StaplesSelecting the app rop riate stap le is just as

importan t to the overall strength and longevity of

the fence as selecting the right wire. Stap le pu ll-

out is a comm on fencing problem wh en usingpressure-treated softwood posts. The lubricating

action of the preservative, combined with the soft

natu re of the wood , makes it easy for staples to

loosen and fall out over time. To avoid th is

pu lling-out action, use 1 3/ 4-inch or 2-inch long,

8- or 9-gauge, hot-dipp ed, galvanized stap les with

cut points and barbs. If you are using untreated

hard wood posts, shorter staples can be used

because they cannot be pu lled ou t of hard wood

very easily.

GatesAlways place gates in logical places so live-

stock will move throu gh easily. Avoid pu tting

gates in the middle of a straight fence. It is best

topu t them in corners. Build or buy sturdy gate

materials, especially hardw are items such as

hinges and closures.

Stock gap s or cattle guards are u seful for high

traffic areas. Cattle guard s can be mad e of various

Table 6. Approximate Prootection Given W ire

by Class 1 and Class 3 Galvanizing


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higher-amperage charge. Their pu lse is extremely

short compared to h igh-imp edan ce controllers.

Since the pu lse length is shor t, the cond uctive

capacity of the wire isnt saturated . Consequ ently,

there is less imped ance or resistance to current

flow, resulting in m ore livestock-influen cing

energy d elivered over miles of fence that weed s

and grass wont short out.If all the fields you plan to fence are not nea r a

120-volt pow er source, you h ave no choice but to

use a battery-operated controller. They do an

excellent job of confining an imals and are very

pop ular controllers because they can be used at

any location w ithout connection to a 120-volt

pow er source. These controllers operate on either

a 12, 24 or 36 volt (1, 2 or 3 batteries) system . The

batteries can be disconnected from the controller

and recharged every two to six weeks dep ending

on the type of charger and the amount used . With

a solar energy collector kit, thebattery can be

recharged da ily for the life of the battery. Deep

cycle, marine and RV type-batteries are best suited

for battery-operated controllers. Batteries de-

signed for u se in autom obiles will not last as long

as deep-cycle batteries.

If your fields ar e near w here they can be

served by a 120-volt controller, it is probably you r

best selection. There is no problem of changing or

recharging batteries and they cost less than the

battery-operated controllers equipp ed w ith solar

kits. Cost of operation is reasonable, averagingaroun d 50 cents a month .

For good an imal control, it is importan t to

match the capacity of the controller to the fence

you wan t to charge. Most man ufacturers ind icate

the strength of the controller by the n um ber of

miles it will power. A good ru le of thum b for

sizing controllers is to determ ine the nu mber of

miles of electrified wire in the fence and add 25

percent to offset any pow er drain caused by grass

and weed s touching the fence. For examp le, if

you have a 5-mile long, 6-strand high-tensile fence

and four of the wires are electrified, you w ouldneed a controller rated at a m inimum of 25 miles

(4 x 5 = 20 + 25% = 25).

GroundingGrounding is very important when using

electric fence controllers, especially with the low -

imped ance types. A minimum of three, 6-foot

long galvanized groun d rods d riven in the groun d

6 feet apart and tied together w ith a #12 gauge

copper w ire are required for the smaller units

(Figure 4). If rocky ground prevents the rods from

being driven into the ground, it is recomm ended

the rods be laid end to end in a deep trench and

tied together with the copper wire. More power-

ful units may require a minimum of eight rods.

Check manufacturers recommend ations for

prop er grounding procedu res. Make sure groundrods a re at least 50 feet from any u tility comp any

ground rod , und erground telephone or power

cable. Firmly attach the ground wire to each rod

with ground clamps.

Figure 4. Grounding Electric Fence Controllers

Lightning ProtectionLightning strikes are a major problem w ith

electric fences. It is rather comm on for lightn ing

to hit a w ire fence directly or ind irectly through a

tree or building near the fence, and then travel as

far as two miles on the fence before it is ground ed.

Whenever possible, disconnect the charger from

the fence line du ring a thund erstorm.

The best and least destructive way to protectelectric fence controllers is to provide a quick pa th

to ground for the lightning charge. Lightning

arrestors and chokes offer some p rotection against

lightning strikes, although they do not gu arantee

complete protection and will notprotect the

controller from a d irect strike (Figure 5). The

choke blocks the extremely high voltage lightning

strike from getting to the charger by making it


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jum p the carbon discs insid e the lightn ing arr es-

tor, then d isperses the charge to ground. Light-

ning always finds the quickest and easiest way to

earth. Thus, earth/ grounding system of the

lightning arr estor must be as good as, or better

than, the grounding system of the controller. Inbad lightning areas, groun ding the top w ire of the

fence has helped protect the controller.

Precautions Never use hom e-made electric fence control-

lers. Nu merous deaths to both hum ans and

animals have occurred from the u se of

home-mad e controllers.

Do not tamper w ith or attempt to repair the

controller. Repairs should be mad e only by

an au thorized service agency or the man u-facturer.

Use only one controller on any one continu-

ous fence.

Never charge a battery on a battery-type

controller with the charger connected to the

fence.

Never attach your electric fence wire to a

utility pole. Leaks from high voltage current

down a w et pole can be very dangerous.

Fasten yellow signs withElectric Fence

painted on both sides to the fence at dis-

tances no more than 200 feet apart.

Construction

Building a fence requires good materials,

prop er construction techniques and good common

jud gm ent. Every fencing job presents slightly

different problems. The following steps are

typically followed in constructing a high-tensile

wire fence. Detailed instructions are provided by

most d istributors of high-tensile wire fence prod -

ucts. Many of the same techniques app ly to the

construction of barbed wire and woven w ire

fences.

Choosing th e Fence LineFirst, carefully p lan you r fencing arrangem ent.

Check property lines closely and arrange cross-

fences to take maximum advantage of your

situation. The fence line shou ld, if possible, avoid

rough, stony, broken, steep areas. With electrified

high-tensile fencing it is easier to zig zag a little

rather than go straight over places which may

Figure 5. Protecting Electric Fence


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need leveling or more p osts and tie downs, and

possibly more m aintenance in the futu re.

In some situa tions it is ad visable to level thearea first. Where this is done, re-grass the area to

prevent erosion and/ or weed growth. Animals

standing on grass get a greater electrical shock

than w hen stand ing on bare soil.

Corner, End and Line Brace Assemblies

Corner-post and end -post assemblies are the

backbone of the fence. A prop erly tensioned high-

tensile fence puts a trem endou s pu ll on these

assemblies. Both corner and end assemblies must

be strong enough to withstand this force. The key

is to build them right and p ut them in deep. Someprod ucers have literally ripped their corner- and/

or end -assemblies out of the ground wh ile tight-

ening the w ires because the p osts were set in the

ground too shallow (Figure 6).

A corner p ost will need a brace assembly for

each fence leading to it. When th e fence is more

than 200 feet long, it is best to use a double span

assembly (Figure 7). The double span assembly is

more than tw ice as strong as a single span. Set the

Figure 6. Corner Brace Assembly


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corner posts leaning back from the d irection of the

fence approximately five degrees. Brace wire

should p ull in the opp osite direction than the

fence is pulling.

When a fence is more th an 650 feet between

corner posts, use braced line post assemblies

every 650 feet in the fence line. A braced line

assembly is the same as a single span braced

corner, except a second diagonal brace w ire is

used to take fence pull in the opposite direction.

In some situations, such as where ad equate post

dep th cannot be achieved, additional bracing may

be required to m aintain tension.

Settin g Fence PostsWooden fence posts can be driven in the

groun d or tamp ed into place. A driven post is 1.7

times as strong as a tamp ed post. Posts larger

than 4 inches may need to be sharp ened to a dull

point or d riven in an auger-drilled p ilot hole

wh en using a post driver. For un iform dep th,

mark the d igging tool or a steel post to the desireddep th. You can drive the post in the ground with

a man ual post-hole driver or a tractor type.

Another m ethod for setting p osts is to dig the

hole larger than the post d iameter, place the post

in the hole and then repack the soil aroun d it.

Center the post in the hole before tamp ing. This

makes tam ping easier and gives the tightest soil-

pack around the post. Replace small amounts of

soil and tam p. Plumb the post wh ile tamp ing to

Figure 7. Double Brace assembly

see that it is in prop er alignment.

The distance between line posts depend s

primarily on topography. On extremely flat land,

line posts are generally spaced from 10 to 16 feet

apart if the fence is not electrified, to as mu ch as

150 feet apart for an electrified fence. Battens or

spacers are installed in all dips or at a m aximu m

of 30 feet apart for five strand s and 50 feet for tw o

to three strands. Line posts are moved closer and

closer together a s the terrain goes from flat to

hilly.

Runn ing WireHigh-tensile w ire is packaged in various size

coils. Wires can be run from the coil one wire at a

time using a payou t spinner, or several at a time

using a mu lti-wire fencer. When walking from the

far corner p ost to the first one, make sure the

wires are in a straight line. If the fence is on flat

land this is easy, but if it is over gently rolling

terrain, the wire can be straightened by lifting it

and letting it drop on its own u ntil it falls onto thesame position. Where the fence line is on very

uneven ground , getting the first wire straight is

not so easy and may have to be done by driving in

two p egs or sighting p osts where each can be seen

at the same time as the corner posts. Then sight

over the guide posts and move them u ntil they are

all in line with the tw o end posts.

Run the bottom w ire out first and tension it

sufficiently as a gu ide for setting line posts. Wires


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are secured to corner, end or gate posts with

crimp ing sleeves or approp riate knots. Secure the

bottom w ire to each line p ost as it is driven to

assist in determining the next post position.

Eight to 10 wires are recomm ended for non -

electric high-tensile wire fences for cattle. Three

to five wires are all that are necessary if the fence

is electrified. String the wires on the inside of the

posts or on the outside of curves. Drive staples

slightly off the ver tical so they strad dle the w ood

grain, as shown in Figure 8. When d riving staples

into posts, rotate the staples around 25 degrees

from the flat surface of the point. Rotating spread s

the legs, which h elps give the staple greater holding

Figure 8. Proper Stapling Procedures


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pow er. Drive staples at an up ward angle into

posts in d ips, and at dow nward angles into posts

on rises. Do not d rive staples in too deeply. The

wire mu st be allowed to slide throu gh the staples

for adjusting tension. All energized wires mu st be

insulated from posts and battens. If using the

fence for p redator control, it is imp ortant to

alternate at least two or three hot wires with theremaining wires. These are used as a ground so

pred ators receive a severe shock when attem pting

to squeeze between the hot and groun d wires.

Always p lainly label electric fences to avoid

danger to p eople.

Tensioning WireAs a safety precaution, always w ear heavy

gloves and eye protection w hen tensioning wire.

Tension each w ire to 200 pou nds with a ratchet in-

line strainer or tightener . Excessive tension not

only dam ages the wire but m ay lift the fence out

of the ground in gullies. The ratchet also perm its

seasonal adjustm ent for temperatu re changes, if

necessary. Use a tension indicator spring to obtain

the p roper w ire tension on each w ire (Figure 9).

Then, tighten all other w ires by feel to match the

tension on the wire with a spring. On runs

shorter than 600 feet, the in-line straineran d

tension spring can be located anywhere along the

fence, usually near one of the end s. How ever, on

long runs, it is recomm ended to p lace them in the

center of the fence so that the wire p ulls in fromboth sides. On long straight run s of more than

600 feet, place them at the friction center w hich is

at the center point between the tw o corners or

ends. On long runs w ith a straight section on one

end and several bends on the other, the friction

center will be in the bend s section rather th an in

the straight section.

Repair and Main tenance

Properly-built and well-maintained fences will

give you the most trou ble-free service for your

money. A maintenance program is a must. In-

clud e some of the following tips in your regular

maintenance program: Keep the fence wires properly stretched.

Fences will natu rally loosen over time or

with seasonal changes. If tighteners are

placed in the fence, check at least twice per

year. Other fences may be tightened by

resetting or by putting several small kinks or

creases in the wire u sing pliers, a hamm er or

special tool designed for this pu rpose.

Splice broken wires when necessary.

Repair or replace anchor post assemblies

whenever they show signs of weakness.

Refasten loose wires to p osts.

Old woven wire and barbed wire fences

wh ich have deteriorated enough to need

replacement can be restored to last for m any

more years by running an electrified w ire on

one or both sides of the fence throu gh offset

brackets attached to the old fence. These

offset brackets are mad e of galvanized high-

tensile wire and are easily attached to the

existing fence. They should be attached at

two-thirds the height of the anim als to be

controlled, next to posts wh ere they w ill beheld m ore securely than sagging on old

wires in the center between tw o posts.

Use herbicides or manu al clearing to keep

weeds and vines from covering fences.

Grass and w eeds touching the wire can

ground it and make the fence ineffective for

controlling livestock. An inexpensive fence

tester should be secured and used frequently

to assure p roper functioning of the fence.

A carpen ters apron is very hand y for

holding na ils, staples and sm all tools, and a

good p air of gloves prevents hand injury

and h elps in gripping w ire. Specialized

fencing p liers are an excellent investmen t for

anyone w ho builds or ma intains fences.

Figure 9. Tensioning Device s


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ReferencesPlanning Fences. 1980. American Association of Vocational Instruction Materials.

Kay, F. W. 1990. Fences for the Farm. University of Georgia Cooperative Extension Service

Publication.

9th Intern ational Power Fence Manual. 1990. Gallagher Power Fence Inc.

Selders, A. W., J. B. McAninch. 1987. High-Tensile Wire Fencing. NRAES-11. North east

Regional Agr icultu ral Engineering Service.


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Visit the Agricultural Extension Service Web site at:

http://www.utextension.utk.edu/

The Agricultural Extension Service offers its programs to all eligible persons regardless of race,

color, national origin, sex, age, disability, religion or veteran status and is an Equal Opportunity Employer.

COOPERATIVE EXTENSION WORK IN AGRICULTURE AND HOME ECONOMICS

The University of Tennessee Institute of Agriculture, U.S. Department of Agriculture,

and county governments cooperating in furtherance of Acts of May 8 and June 30, 1914.

Agricultural Extension Service

Charles L. Norman, Dean

PB1541 -2.5M-5/01(Rep) E12-4315-00-02-01

Planning & Building Fences on the Farm

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