Amprobe A-5000 Sheath Fault Locator Manuale utente

A-5000

Sheath Fault Locator

Users Manual

Mode d’emploi•

Bedienungshandbuch•

Manuale d’Uso•

Manual de uso•

Användarhandbok•

1

English

A-5000

Sheath Fault Locator

Users Manual

A5000_Rev002

2

Limited Warranty and Limitation of Liability

Your Amprobe product will be free from defects in material and workmanship for 1 year from the date of purchase. This

warranty does not cover fuses, disposable batteries or damage from accident, neglect, misuse, alteration, contamination, or

abnormal conditions of operation or handling. Amprobe’s warranty obligation is limited, at Amprobe’s option, to refund of

the purchase price, free of charge repair, or replacement of a defective product . Resellers are not authorized to extend any

other warranty on Amprobe’s behalf. To obtain service during the warranty period, return the product with proof of purchase

to an authorized Amprobe Test Tools Service Center or to an Amprobe dealer or distributor. See Repair Section for details. This

warranty is your only remedy . All other warranties - whether express, implied or statutory - including implied warranties of

ﬁtness for a particular purpose or merchantability, are hereby excluded. Neither Amprobe nor its parent company or afﬁliates

shall be liable for any special, indirect, incidental or consequential damages or losses, arising from any cause or theory. Since

some states or countries do not allow the exclusion or limitation of an implied warranty or of incidental or consequential

damages, this limitation of liability may not apply to you.

Repair

All test tools returned for warranty or non-warranty repair or for calibration should be accompanied by the following: your

name, company’s name, address, telephone number, and proof of purchase. Additionally, please include a brief description of

the problem or the service requested and include the test leads with the meter. Non-warranty repair or replacement charges

should be remitted in the form of a check, a money order, credit card with expiration date, or a purchase order made payable to

Amprobe® Test Tools.

In-Warranty Repairs and Replacement – All Countries

Please read the warranty statement and check your battery before requesting repair. During the warranty period any defective

test tool can be returned to your Amprobe® Test Tools distributor for an exchange for the same or like product. Please check the

“Where to Buy” section on www.amprobe.com for a list of distributors near you. Additionally, in the United States and Canada

In-Warranty repair and replacement units can also be sent to a Amprobe® Test Tools Service Center (see below for address).

Non-Warranty Repairs and Replacement – US and Canada

Non-warranty repairs in the United States and Canada should be sent to a Amprobe® Test Tools Service Center. Call Amprobe®

Test Tools or inquire at your point of purchase for current repair and replacement rates.

In USA In Canada

Amprobe Test Tools Amprobe Test Tools

Everett, WA 98203 Mississauga, ON L4Z 1X9

Tel: 888-993-5853 Tel: 905-890-7600

Fax: 425-446-6390 Fax: 905-890-6866

Non-Warranty Repairs and Replacement – Europe

European non-warranty units can be replaced by your Amprobe® Test Tools distributor for a nominal charge. Please check the

“Where to Buy” section on www.amprobe.com for a list of distributors near you.

European Correspondence Address*

Amprobe® Test Tools Europe

Beha-Amprobe GmbH

In den Engematten 14

79286 Glottertal, Germany

Tel.: +49 (0) 7684 8009 – 0

*(Correspondence only – no repair or replacement available from this address. European customers please contact your

distributor.)

3

➊

On/Off Button

➋

Reference indicator

➌

Active indicator

➍

Bargraph indicator

➎

A-Frame spikes

4

A-5000

Sheath Fault Locator

CONTENTS

Introduction ................................................................................................................................................................................................ 5

General Information and Safety .............................................................................................................................................................. 5

Symbols used in this manual ................................................................................................................................................................ 5

Safety Precautions ................................................................................................................................................................................ 5

A-5000 Sheath Fault Locator Quick Start Guide For The Experienced User ........................................................................................... 5

A-5000 Receiver Technical Speciﬁcations .................................................................................................................................................. 8

Linear A-Frames For Telecom Utilities: ................................................................................................................................................ 8

A-Frame Receiver Controls And Indicators .......................................................................................................................................... 8

Principles Of Operation ............................................................................................................................................................................. 9

Functional Theory ................................................................................................................................................................................. 9

Calibration Test Procedure ...................................................................................................................................................................... 12

Operation ................................................................................................................................................................................................. 13

Synchronize The A-Frame Receiver .................................................................................................................................................... 13

Conﬁrm That A Fault Exists ................................................................................................................................................................ 13

Trace The Cable With The R-5000 Receiver ....................................................................................................................................... 13

Pinpoint The Fault .............................................................................................................................................................................. 13

Verify The Fault ................................................................................................................................................................................... 14

Advanced Techniques .............................................................................................................................................................................. 14

Faults Under Inaccessible Surfaces ..................................................................................................................................................... 14

Faults Under Pavement ...................................................................................................................................................................... 15

Long Distance Tracing ........................................................................................................................................................................ 15

High And Low Impedance Faults ....................................................................................................................................................... 16

Multiple Faults .................................................................................................................................................................................... 16

Maintenance ............................................................................................................................................................................................. 16

A-5000 Receiver Battery Replacement. ............................................................................................................................................. 16

Technical Speciﬁcations ........................................................................................................................................................................... 17

Appendix .................................................................................................................................................................................................. 17

APWA Marking Colors ........................................................................................................................................................................ 17

5

INTRODUCTION

The Amprobe AT-5000 Utility Locator with Sheath Fault Locating (SFL) option is designed to detect and pinpoint sheath and

other conductor faults that are in direct contact with the earth.

The AT-5000 with A-5000 (SFL) offers these unique features:

Fault level measurement at the transmitter•

Simultaneous fault ﬁnding and line tracing•

LCD bar graph representing the A-Frame signal strength for judging the proximity to faults, comparing multiple faults, and •

detecting pinholes and “trees” in a power cable

Detection of low and high resistance faults•

Automatic battery checking and low battery warning•

Non-polarized A-Frame•

Single-handed operation. No need to carry an R-5000 receiver as well as an A-frame during fault locating•

Active SFL ohmmeter and voltmeter in the Transmitter•

GENERAL INFORMATION AND SAFETY

This manual contains basic advice for the installation and operation of Amprobe Utility Line and Sheath Fault Locators as well

as accompanying accessories. The manufacturer is not liable for damage to material or humans due to non-observance of the

instructions and safety advice provided in this manual. Therefore, this manual should be provided and reviewed by all personnel

associated with the line and sheath fault locating equipment.

Symbols used in this manual

Important instructions concerning the protection of staff and equipment as well as technical safety within this document are

labeled with one of the following symbols:



Indicates a potentially hazardous situation, which, if not avoided, may result in minor or moderate injury or material

damage.



Indicates a potentially hazardous situation, which, if not avoided, could result in death or serious injury.

Notes have important information and useful tips on the operation of your equipment. Non-observance may result

in incorrect measurement results.

Operating personnel

Amprobe utility line and sheath fault locators are intended for use by utility and contractor professionals.

Repair and maintenance

Repairs and service must only be done by Amprobe.

Safety Precautions

Observed safety practices

Familiarize yourself with all required safety practices of the local utility company, or other owner of the plant before entering an

access area, or connecting an Amprobe transmitter.

Ensure that the line is de-energized and out of service, BEFORE connecting the transmitter directly to any conductor. NEVER

make a direct connection to a live power cable.

Follow the appropriate safety procedures to avoid the risk of injury if using a clamp on energized electrical or control lines.

Pay special attention when using a locator in high trafﬁc areas.

Intended application

Safe operation is only realized when using the equipment for its intended purpose. Using the equipment for other purposes

may lead to human danger and equipment damage.

The limits described under the technical data section may not be exceeded.

A-5000 SHEATH FAULT LOCATOR QUICK START GUIDE FOR THE EXPERIENCED USER

Check Batteries Prior to Departing for the Field 1.

Check the battery level in the Transmitter, Receiver, and A-Frame by powering up each instrument.

Maximum use of the Transmitter’s SFL feature requires that the battery be fully-charged prior to ﬁeld use. Amprobe

recommends charging the battery to full capacity before locating faults.

Replace/recharge if necessary. Turn the instruments OFF.

Ensure All Conductors Are De-Energized2.

Lift Grounds3.

Lift Grounds (of all conductors in the circuit) at both ends of the faulted cable section.

WARNING When the T-5000 transmitter is ON, the external OUTPUT JACK produces a high voltage. Do not touch the jack!

Electrical shock will result!

Attach Transmitter to Conductor – Check Fault Resistance4.

Make sure T-5000 transmitter is powered OFF.1.

6

Plug Black and Red conductive leads into the transmitter.2.

Stretch the Black-lead 180° away from conductor.3.

Push the ground rod into earth and clamp the Black lead to ground rod. Establish the best ground possible. See Figure 3-14.

Figure 3-1: Clamping Black Lead to Ground Rod; Clamping Red Lead to Conductor

Clamp Red lead to target conductor sheath. See Figure 3-15.

Push T-5000 transmitter SFL key. Check measured fault resistance on transmitter display. See Figure 3-2 6.

Fault Severity Guide:

0-100 KΩ – Severe Fault

100 – 500 KΩ – Medium Fault

1 MΩ and above – Light Faults

Figure 3-2: Transmitter display in SFL mode

Select frequency - 9.8 KHz or 82 KHz, pressing the f button on the Transmitter keypad.7.

Use the R-5000 Utility Line Locator Receiver to Trace the Cable5.

Press the frequency softkey (Freq) on the receiver until the frequency selected on the transmitter is displayed. Trace and mark

the cable as you proceed towards the fault.

Synchronize the A-5000 A-Frame Receiver and Establish Reference Value of Fault 6.

(A-Frame receiver has a one-color band above each spike (Black or White)

Hold the A-5000 Receiver so the spike with the Black band is about two (2) steps away from the ground rod and the spike 1.

with the white band is in-line with the targeted cable. The A-5000 receiver must be placed as shown in Figure 3-3 for

synchronization and for unit to operate correctly. Push the A-5000 spikes ﬁrmly into the ground. Turn the A-5000 ON.

Wait until the arrow ﬂashes.

7

Figure 3-3: Positioning of A-5000 Receiver for Synchronization

Monitor bar-graph LCD display for arrow direction. If the arrow points AWAY from the ground rod, there is a fault.2.

If the arrow points TOWARDS the ground rod, there is no fault, and grounds and connections need to be rechecked.3.

The number of bars on the LCD indicates the potential gradient associated with the fault at the synchronization location.4.

The number of bars will decrease when you move away from the synchronization location and will increase when you get 5.

closer to the targeted fault. See Figure 3-4

Figure 3-4 : Locating the Cable Fault with A-5000 Receiver

Pinpoint the Fault7.

Keep the A-5000 parallel to the target cable.1.

Insert the A-5000 ﬁrmly in the ground every 10’ – 20’ (3 -6 m). Follow the arrow.2.

When the arrow changes direction, the fault may have been reached or passed.3.

Look at the number of bars activated as well as the “Actual” LCD reading and compare them to number of bars you

read at synchronization point as well as the “Reference” LCD reading. If the number of bars or the “Actual” and

“Reference” readings are similar to the number of bars at synchronization point, you have located the main fault.

8

Backtrack. 4.

Insert the A-5000 every 2’ (.5 m) until the arrow changes direction again. 5.

Move the A-5000 across the cable until a slight movement causes the arrow to change direction. The fault is located at the 6.

center of the A-5000.

Check entire cable for multiple faults. If more faults are present, check the “Active” LCD number at each fault site and 7.

compare it to the “Reference” number. The higher the “Active” number the larger the fault.

A-5000 RECEIVER TECHNICAL SPECIFICATIONS

Linear A-Frames For Telecom Utilities:

Telecom faults, however, are typically higher resistance faults than power. The Linear A-frame A-5000 provides greater sensitivity

in the fault range of 100 KΩ – 10 MΩ to detect multiple faults in a cable.

A-Frame Receiver Controls And Indicators

See Figure 4-1 for the location of the Receiver controls described below:

Figure 4-1: A-5000 Controls and Indicators

On/Off Button:

Push and release to turn ON. Push and release to turn OFF.

LCD Bar Graph Display:

The bar graph indicates three types of information:

Battery Status:

The solid bars indicate the battery level. If only one bar appears, replace the battery. The battery status is displayed for three

(3) seconds at Power ON.

Direction of Fault:

The ﬂashing arrows will display the direction to the fault

Magnitude of Fault

The bar graph consists of twelve (12) bars with each bar representing the magnitude of the fault(s) as described below.

9

Impedance (Ω) Linear Active/Reference Bars

450 828 12

1K 694 11-12

5K 413 11

10K 302 10-11

20K 222 10

30K 182 10

50K 139 9-10

100K 90 8-9

327K 45 7-8

1M 21 6-7

Additional A-Frame Receiver Features

Battery Access Plate

Located on the underside of Receiver control panel. Remove the two thumbscrews to release the plate. See Figure 9-1.

Conductive Pads

The A-Frame Receiver is shipped with two protective foam pads with large washers attached to the Receiver probes. These

pads are used for tracing on dry, hard surfaces. Protect and save these conductive pads and washers.

PRINCIPLES OF OPERATION

Functional Theory

Reviewing the basics of sheath fault locating is a valuable exercise before proceeding even for experienced users. This will

improve the chances of ﬁnding the fault and saving time.

Comparing electrical current to water ﬂowing through a pipe applies extremely well to fault locating. Just like trying to ﬁnd a

leak in a water pipe, you might seal off one end, pump water into the other, and look for water to appear near the leak. The

principles of sheath fault locating are identical. The cable equivalent of sealing off the pipe is to lift all connections at both

ends of the cable, creating a high resistance open condition. The “water” in this case is the current ﬂowing through the cable

towards the fault. We look for the current “leak” with an A-Frame.

Both ends of the cable must be disconnected from ground.

The T-5000 transmitter applies a low frequency signal between an isolated conductor with an earth fault and another ground

point. This 4.8 Hz signal is induced into the ground from the fault location. The A-5000 Receiver contact probes detect this

signal pattern.

A typical hookup for locating a sheath fault, also called a shield-to-earth fault, is illustrated in Figure 5-1.

10

Figure 5-1: Typical T-5000 Transmitter Connection

1 Black Lead

2 Red Lead

3 Ground Rod

4 Fault

5 Faulty conductor open on both ends

As current ﬂows from the transmitter and through the fault, an earth voltage gradient ﬁeld is created. Its center is at the

fault. This gradient ﬁeld has a pattern as depicted in Figure 5-2, like pond water ripples when you throw a rock in it or

the rings of a tree stump.)

11

Figure 5-2: Signal Pattern Around Fault and Ground Point

The A-Frame Receiver compares the readings taken by the two probes and determines the direction and size of the fault.

Directional blinking arrows guide the operator to the exact source of the fault. The A-5000 bar graph and numerical active LCD

display indicates the relative distance to the fault and it is size.

Earth Voltage Gradient

Note in Figure 5-2 that the gradient pattern appears to be concentric circles near the fault. Properly interpreting this pattern is

the key to successful operation of the A-5000.

Equipotentials

The circles shown in Figure 5-2 represent lines of equal voltage. The boxes show what the bar graph will display with the A-5000

in different positions. Thus, if the A-5000 A-Frame were inserted so that both of the ground spikes were on the same circle,

there would be no difference in voltage between them. The bar graph will show zero, the arrows will become erratic and the

numerical active display will show a zero. One of these positions occurs when the fault is directly between the spikes.

This result can also occur midway between the ground spike and a fault and when the A-5000 is exactly perpendicular to the

fault. There is a return ﬁeld around the transmitter ground spike. As you move toward the fault, the bars and the active

numerical number will decrease until you reach the midpoint between the fault and ground spikes. At the half waypoint

between the fault and ground spike, the signal strength is at it is absolute lowest. At this point the bar graph and active display

will show zero and the arrows become erratic.

To determine if you are midway between faults or directly over a fault, move the A-5000 further from the transmitter and

measure again. If the arrows tell you to continue in this direction, the zero point was a midpoint. If the arrows tell you to return

toward the transmitter, the zero point was a fault. As you continue, they will increase until you reach the fault.

Nearly 70% of the signal exists within the last 1/3 of the distance between the ground spike and the fault. The amount of signal

measured and displayed by the A-5000 is proportional to the number of ﬁeld lines in Figure 5-2 between the A-5000 A-Frame

spikes. Thus, the maximum signal point occurs when one A-Frame spike is directly above the fault.

By probing around the ground point, a user can learn what to expect at the fault from the A-Frame bar graph response. As

shown in Figure 5-2, the signal pattern around the fault and ground point is identical (if there are no nearby conductors). This

means that the A-Frame will react the same way around the fault as at the ground point.

As you move toward the fault, the bars and the active numerical display will decrease until you reach the midpoint between the

fault and ground spike. As you continue, they will increase until you reach the fault.

Multiple Fault Patterns

The signal pattern created by two faults in a line is depicted in Figure 5-3. The two faults are shown without the ground point.

Notice that from a distance the two faults will have the appearance of a single fault due to the equipotential circle around

them both. As you get closer, the individual faults become apparent. There is an area between two faults where the A-Frame

may give a false indication of another fault. This is caused by the two faults canceling each other. Errors can be avoided in this

situation by following the procedure described in Section 7.7.

We recommend that multiple faults be attacked one at a time. Whenever a fault is positively located, it should be repaired

before looking for the other faults.

12

F1

F2

Figure 5-3: Multiple Fault Signal Patterns

Distortion Due to Adjacent Conductors

Whenever a non-insulated adjacent conductor lies between a fault and the ground return point, the return current tends to

concentrate on the conductor instead of ﬂowing through the earth. This situation can shrink the signal pattern near the fault,

which would tend to reduce the detectable signal away from the fault. Possible distortion problems such as the described

situation can be avoided by ﬁrst tracing the faulty conductor and looking for adjacent conductors prior to fault locating.

CALIBRATION TEST PROCEDURE

Perform this instrument test procedure on a lawn prior to ﬁeld site use. If grass or dirt is not available, indoor carpeting may be

used.

Check the Batteries1.

Turn the T-5000 transmitter ON. The transmitter LCD will display the battery capacity level. Ensure the transmitter battery is

fully charged for optimal operation. Turn the transmitter OFF.

Turn the A-5000 Receiver ON. The solid bars indicate the battery level. If only one bar appears, replace the battery (1 each,

9V). The battery status is ON for 3 seconds at turn on.

Connect the Test Cables2.

Connect the Black and red connection leads to the transmitter OUTPUT JACK. See Figure 6-1.

Figure 6-1: Checkout Test Set-Up

Spread the Test Leads as Far Apart as Possible3.

Insert the ground spike and attach the Black cable. Insert a screwdriver into the ground and connect the Red cable to it,

creating a simulated fault.

This test can also be done by pushing the metal end of the clamps directly into the ground so that they make electrical

contact. When using a carpet in this checkout procedure connect test cable clamps directly to the carpet.

Push the SFL T-5000 transmitter button on the keypad4.

Wait for the SFL high-voltage output to be generated and observe the fault resistance transmitter display.

Synchronize the Receiver5.

Hold the A-5000 so that the black spike is closer to the ground connection. Push the A-Frame ﬁrmly into the ground.

Push the A-5000 Receiver On/Off Switch to ON6.

13

The A-Frame Receiver will repeat its battery test. After the battery test, the arrow facing the simulated fault (Red test clamp)

ﬂashes and a potential gradient number is shown on the Active and Reference LCD display.

Rotate the A-5000 180°7.

Note that the arrow now facing the red test clamp ﬂashes. As the A-Frame is moved around the fault the arrow closest to the

simulated fault should ﬂash.

OPERATION

Synchronize The A-Frame Receiver

By synchronizing, the A-5000 memorizes the phase of the transmitter signal. This allows it to recognize the reverse phase signal

coming from the fault and direct you to it.

Resynchronize the Receiver every 45 minutes to maintain optimum calibration. You may do this near the ground rod or

near a fault. At the ground rod, the black A-Frame spike must be nearer to the ground rod with the white spike facing

toward the fault. At a fault, the white A-Frame spike must be nearer to the fault.

Hold the A-5000 so that the black spike is closest to the ground rod.1.

Push the A-Frame spikes into the ground.2.

Switch the A-5000 Receiver ON. Wait until the arrow ﬂashes on the bar graph.3.

If the arrow points away from the ground spike, there is a fault.4.

If the arrow points towards the ground spike, there is no fault. Recheck the grounds and connections if a fault is wrongly 5.

given. See Figure 7-1.

Figure 7-1: Synchronizing the A-5000

Conﬁrm That A Fault Exists

Remove the A-Frame from the ground.1.

Rotate it 180° and re-insert it into the ground. The arrows should reverse directions and point away from the ground spike.2.

Trace The Cable With The R-5000 Receiver

The AT-5000 Utility Line Locator allows you to trace the line and search for the fault at the same time.

Check the R-5000 Receiver for cable tracing frequency. Aim the Receiver at the Red lead and cycle through the Receiver 1.

frequencies – 9.8 KHz or 82 KHz, to conﬁrm that the selected tracing frequency is being received.

Trace and mark the cable as you proceed towards the fault.2.

Pinpoint The Fault

Keep the A-5000 parallel to the target cable1.

Insert the A-Frame every 10’ – 20’ (3 - 6 m). Follow the arrow and monitor the active number.2.

When locating with the A-5000, make sure that the probes are inserted well into the ground. A good physical ground 3.

connection is needed to receive strong signal.

14

When the arrow changes direction, back track. Check the “Active” LCD number and compare it to the “Reference” LCD 4.

number. If both active and reference numbers have the same or similar value, you have found the major fault.

Insert the A-Frame every 2’ (50 cm) until the arrow changes direction again, then turn it 90 degrees. Check for obvious causes 5.

where a fault is suspected, such as recent excavation.

Continue to move the A-Frame across the cable until a slight movement causes the arrow to change directions. When this 6.

happens, the fault is located at the center of the A-Frame.

Verify The Fault

Move slightly off to one side of the cable.1.

Insert the A-Frame into the ground at various positions around the suspected fault site (like the hands of a clock).2.

The arrow should always point toward the fault.3.

Place the other spike in the ground at the fault site and repeat the process. The arrow should always point inward, toward 4.

the fault. See Figure 7-2.

Figure 7-2: Fault Conﬁrmation

ADVANCED TECHNIQUES

Faults Under Inaccessible Surfaces

When the faults exist beneath a paved or other inaccessible area, the fault may be located using one of the following methods.

Perpendicular Method

Carefully trace the location of the faulty conductor. Hold the A-5000 parallel to the cable path. As you move away from the

ground rod the bar graph and the active number will gradually decrease until reaching the midpoint. It will then increase until

reaching the fault. When the A-Frame center passes a line perpendicular to the Sheath fault, the directional arrow indicators

will rapidly change positions and the bar graph and active number will drop to zero. See Figure 8-1.

Paved Surface

Ca ble Fault

Figure 8-1: Perpendicular Method

Triangulation Method

As shown in Figure 8-2, (the point where the signal strength is a minimum) if the A-5000 is positioned exactly on an

equipotential circle, a perpendicular line from the center of the A-Frame will pass through the fault. The intersection of any two

such perpendicular lines deﬁnes the fault location.

15

Paved Surface

Ca ble Fault

Figure 8-2: Triangulation Method

To ﬁnd an equipotential circle (see Figure 8-3) insert the A-Frame into the ground and pivot around one spike. Rotate the

A-Frame back and forth until the exact point is found where the ﬂashing arrows change direction. The A-Frame is now on

an equipotential circle and is perpendicular to the fault. By marking this line and repeating the process with the A-Frame at

another nearby location, the two lines will intersect or cross at the fault.

Figure 8-3: Locating an Equipotential Circle

Faults Under Pavement

Faults under pavement or other slightly conductive surfaces can be found using the foam pads supplied with the unit. Saturate

the pads with water and insert the A-Frame spikes into the pads. Locate the fault as you normally would. Be sure to keep the

pads as moist as possible, but do not let the water form a continuous puddle between the pads as this will short out the signal.

Long Distance Tracing

As the distance to the fault increases, the signal picked up by the A-5000 is proportionally reduced. This condition can lead to

problems if the signal levels are reduced to the point that they can no longer be detected by the A-Frame.

Whenever working with weak signals due to long distance faults (or other reasons), increased sensitivity can be obtained by

extending the distance between the A-Frame spikes using the extension cable. This extension method can be applied to any of

the previously discussed methods including the conductive foam pads. When working with very long distances, as in ﬁber optic

runs, the sensitivity can be increased even further using a longer insulated wire to extend the A-Frame span. See Figure 8-4.

16

Figure 8-4: Fault Location Using Extension Cable for Increased Sensitivity

High And Low Impedance Faults

Before beginning a fault search it is a good idea to know the severity of the fault. This is measured in terms of its resistance

or impedance to ground. Faults where the ground is wet and/or a very large piece of the insulation is missing are found at the

low end of the range (<500 Ohms). Conditions where the ground is very dry and/or the actual fault is a small pinhole where the

conductor has a very small ground contact area are found at the high end of the fault range (>1-3 MΩ).

A low impedance fault is the easiest to ﬁnd since there is more signal to detect.

Generally, the more bars and a higher number displayed at synchronization, the larger the fault.

A high impedance fault is more difﬁcult to locate. Characteristically, the A-5000 Receiver may not detect the signal after moving

a short distance away from the ground point. The higher the impedance of the fault, the closer you must be to detect it.

Example

If the A-Frame only reliably points away from the ground connection within 20’ (3 m), then the A-frame will only detect the

fault within about 20’ (3 m). Outside this distance the signal is too weak to reliably detect.

For this reason we highly recommend tracing and marking the line before searching out high impedance faults.

Multiple Faults

Locating multiple faults is the most difﬁcult and confusing fault situation. It is especially important in this case to accurately

trace the faulty conductor before beginning the fault search. Stay exactly above the line if possible and verify each suspected

fault by monitoring the active number to see which fault has the higher number. Remember that a very strong or low

impedance fault will mask the detection of a weak or high impedance fault. The safest and best way to ﬁnd multiple faults is to

repair each fault as it is positively identiﬁed and then continue the search. See Figure 5-3.

MAINTENANCE

A-5000 Receiver Battery Replacement.

Loosen the two thumbscrews located on the underside of the Receiver housing. Gently pull out battery door. Be careful not

to pull on the battery wires. Remove battery from battery holder and disconnect battery. Reverse procedure for installing new

battery.

17

C onne c tor

Figure 9-1: A-5000 Receiver Battery Replacement

TECHNICAL SPECIFICATIONS

Frequency: 4.8 Hz Crystal Controlled

Input Sensitivity: 5 MV

Sensitivity Control: Automatic

Active/Reference Signal Sensitivity Logarithmic: 0 − 120

Linear: 0 − 999

Battery: 9 V NEDA 1604 or equivalent

Battery Life: 100 hr. continuous use

Battery Test: Automatic at power ON for 3 sec.

Weight: 4.4 lb (2.0 kg)

Dimensions: 32” H x 22” W x 1” D

(81 cm H x 56 cm W x 2.5 cm D)

Operational Temp: -4°F − +120°F

(-20°C − +50°C)

APPENDIX

APWA Marking Colors

The following color markings have been established by the American Public Works Association (APWA):

Conductor Color

Electric power lines, cables, or conduits Red

Communication lines, cables, Conduits, CATV Orange

Gas, oil, petroleum, or other gaseous materials Yellow

Sewers, storm and sanitary, drain lines Green

Water, irrigation, or slurry lines Blue

If you have any questions regarding marking requirements or procedures in the United States, please call your local One Call

Center. International customers: please check with your local regulatory authorities or utility companies required color markings

may vary between different countries.

18

La pagina sta caricando ...

Amprobe A-5000 Sheath Fault Locator Manuale utente

Amprobe A-5000 Sheath Fault Locator Manuale utente

in altre lingue

Documenti correlati

Altri documenti