Underground Cable Tracing
&
Earth Return (Sheath) Fault Locating
[ Basic Concept ]
Prepared By:
Roger C. Valencia
U.S. & International Technical Service Engineer
3M Test & Measurement Systems
3M Austin Center
Austin, TX, USA - March 1996
1
INTRODUCING
The New And Most Advanced Cable & Earth Return (Sheath) Fault Locators
A GLOBAL PRODUCT
FOR
GLOBAL SOLUTIONS
2
Dynatel TM 2200 Series Cable & Earth Return (Sheath) Fault Locators
Dynatel
2273
TM
cm
ACCESSORY COMPARTMENT
Trace
Frequency
Fault / Tone
On
Hz
Off
Dynatel
TM
2273
Trace
Off
Ref
On
Output Level
Volume
TRANSMITTER
Gain Adjust
Depth/Current
RECEIVER
3
THE RADIO BROADCAST SYSTEM
RADIO
TRANSMITTER
L
GNA
I
S
O
I
RAD
RADIO
RECEIVER
THE BASIC CONCEPT OF CABLE TRACING IS THE
SAME AS THE ONE USED IN A RADIO BROADCAST
SYSTEM.
BOTH SYSTEMS MAKE USE OF THE FOLLOWING:
? ? TRANSMITTER
? ? RECEIVER
BY USING A UNI-DIRECTIONAL ANTENNA IN THE
RECEIVER, THE DIRECTION AND LOCATION OF THE
SIGNAL SOURCE CAN EASILY BE DETERMINED.
4
Basic Concept of Cable Tracing
Receiver
Strong Signal
Decaying Signal
Cable Shield
Red Clip
Near-End
Ground
Removed
Far-End
Ground
Current Flow
Transmitter
Ground Rod
Soil
Black Clip
Current Flow
? In cable tracing, the trace conductor is connected to the output of the Transmitter. The CABLE and
EARTH (SOIL) must form an electrical circuit where signal current can flow through.
? As the current flows through the cable, its entire length radiates a signal allowing one to trace the cable
path using a Receiver.
? Also, as the signal travels further out, its strength gradually deteriorates due to the increasing resistance of
the conductors and the capacitances between them.
5
TERMS COMMONLY USED IN CABLE TRACING
? TRACE CONDUCTOR - any metallic component of a
cable which is used to trace the cable path. (Ex:
Cable Shield, a conductor of a power cable, or a
telephone wire or pair inside a telephone cable, etc.)
? TRACE FREQUENCY - is the selected transmit frequency
(Audio or RF) to trace the cable path.
? NEAR-END GROUND - is the grounding point of the
trace conductor which is located closer to the
Transmitter.
? FAR-END GROUND - is the remote grounding point of
the trace conductor which is located further away
from the Transmitter.
? TARGET CABLE - the cable being traced.
6
TERMS COMMONLY USED IN CABLE TRACING
(con’t ...)
? CONTINUOUSLY GROUNDED CABLE - a cable having its
entire outer metallic sheath in direct contact with Earth
(Soil). (Ex: A lead cable having no outer insulating jacket).
? CENTER / INNER CONDUCTOR - Any conductor other than,
but within, the metallic shield of a cable. (Ex: the center
conductor of a coax cable (CATV or a shielded power cable)
a wire or a pair of conductors within a shielded telephone
cable, etc.).
? EARTH RETURN FAULT - An electrical leakage path between
any cable conductor and Earth (Soil).
? SHEATH FAULT - The same as EARTH RETURN FAULT but
the current leakage path is between the cable SHIELD and
Earth (Soil).
7
CABLE TRACING MODES
? PEAK
? NULL
?
DIFFERENTIAL
? SPECIAL PEAK
8
CABLE TRACING - PEAK MODE
Note:
In this mode, a flag appears below
the PEAK symbol on top of the
LCD display.
Display Indications:
? Location #1:
?? Bargraph - moves to max.
closed
position towards center
of the
display.
? ? Numeric Indicator Higher
compared to the
reading in
either location
#2 or #3.
? ? Audio Tone Stronger compared
to that of
location #2 or #3.
? Location #2:
? ? Bargraph - Opens up or moves
away from center of display.
? ? Numeric Indicator - Lower
compared to that location #1.
? ? Audio Tone - Weaker
compared
to that of location
#1.
? Location #3:
? ? Bargraph - Opens up or moves
away from center of display.
? ? Numeric Indicator - Lower
compared to that of location
#1.
? ? Audio Tone - Weaker
compared
to that location
#1.
PEAK
TRACE
RECEIVER
2
1
3
SOIL
TARGET CABLE
9
Cable Tracing - Peak Mode
DynatelTM 2273
Trace
Frequency
Receiver
Fault/Tone
ON
Hz
OFF
Ref
Volume
Gain Adjust Depth/Current
Cable
10
Cable Tracing - Peak Mode
DynatelTM 2273
Receiver
Trace
Frequency
Fault/Tone
ON
Hz
OFF
Ref
Volume
Cable
Gain Adjust Depth/Current
11
CABLE TRACING - NULL MODE
Note:
In this mode, a flag appears below the
NULL symbol on top of the LCD
display.
Display Indications:
NULL
TRACE
Location #1:
? Bargraph - Moves to max.
closed
position towards center of
display.
? ? Numeric Indicator - Lower
compared to that of
location #2
or #3.
? Audio Tone - Weaker
compared to
that of location #2
or #3.
Location #2:
RECEIVER
2
1
? Bargraph - Opens up away from
center of display.
? Numeric Indicator - Higher
compared to that of location #1.
? Audio Tone - Stronger than that of
location #1.
Loaction #3:
? ? Bargraph - Opens up away from
center of display.
? ? Numeric Indicator - Higher
compared to that of location
#1. ? ? Audio Tone - Stronger
compared to
that of location #1.
3
SOIL
TARGET CABLE
12
Cable Tracing - Null Mode
DynatelTM 2273
Trace
Frequency
Fault/Tone
ON
Hz
OFF
Ref
Volume
Gain Adjust Depth/Current
13
Cable Tracing - Null Mode
DynatelTM 2273
Trace
Frequency
Fault/Tone
ON
Hz
OFF
Ref
Volume
Gain Adjust Depth/Current
14
DIFFERENTIAL MODE
(Basic Theory)
Note:
In DIFFERENTIAL mode, two sets of
antennas are used, UPPER (Peak &
Null coils) and the LOWER (Peak &
Null
coils).
The “D”istance between the two antenna
sets was precisely calculated so that
when the RECEIVER is positioned
directly over the TARGET CABLE, the
UPPER antenna set should receive
exactly 50% of whatever signal level the
LOWER set is receiving.
In this situation, this signal phase
relationship between the two sets of
antennas is considered to be at ZERO
VALUE.
Upper Antenna
Set
Null Coil
Peak Coil
D
Lower Antenna
Set
SOIL
TARGET CABLE
15
DIFFERENTIAL MODE
(Basic Theory - con’t ...)
POSITIVE
ZERO
3 SIGNAL PHASE VALUES
NEGATIVE
RECEIVER
? ? Location #1 - Zero Value
Receiver is exactly over target
cable and the UPPER antenna
set is receiving exactly 50% of
whatever signal level is being
received by the LOWER set.
? ? Location #2 - Positive Value
Receiver is moved to the
LEFT of the target cable.
2
1
3
SOIL
? ? Location #3 - Negative Value
Receiver is moved to the
RIGHT of the target cable.
TARGET CABLE
16
CABLE TRACING - DIFFERENTIAL MODE
(Basic Theory - con’t . . . )
DISPLAY
INDICATIONS
Location #1: ZERO-VALUE
? Bargraph - moves to a
maximum closed
position towards the
center of the display.
? Numeric indicator reads higher
compared
to location
#2 or #3.
? Directional Arrows both Left & Right
arrows appear at the
center of the LCD
display.
? Audio Tone - solid (not
warbling)
POSITIVE
VALUE
ZERO-VALUE
NEGATIVE
VALUE
RECEIVER
UPPER
ANTENNA SET
( Peak & Null Coils)
2
1
3
LOWER
ANTENNA SET
( Peak & Null Coils)
SOIL
TARGET CABLE
17
Cable Tracing - Differential Mode
DynatelTM 2273
Trace
Frequency
Fault/Tone
ON
Hz
OFF
Ref
Volume
Gain Adjust Depth/Current
18
DISPLAY
INDICATIONS
(con’t...)
Note:
When the RECEIVER is moved
away from the TARGET
CABLE to the LEFT (location
#2), the signal phase relationship
changes into a POSITIVE
VALUE.
Location #2: Positive Value
? Bargraph - Opens up and
moves away from the
center of the display.
? Numeric Indicator - reads
lower compared to
location #1.
? Directional Arrow - the
RIGHT arrow will
appear in the display,
meaning the RECEIVER
should be moved to the
right.
? Audio Tone - Low, warbling.
CABLE TRACING - DIFFERENTIAL MODE
(Basic Theory - con’t . . . )
POSITIVE
VALUE
ZERO-VALUE
NEGATIVE
VALUE
RECEIVER
UPPER
ANTENNA SET
( Peak & Null Coils)
2
1
3
LOWER
ANTENNA SET
( Peak & Null Coils)
SOIL
TARGET CABLE
19
Cable Tracing - Differential Mode
DynatelTM 2273
Trace
Frequency
Fault/Tone
ON
Hz
OFF
Ref
Volume
Gain Adjust Depth/Current
20
CABLE TRACING - DIFFERENTIAL MODE
(Basic Theory - con’t...)
DISPLAY
INDICATIONS
(con’t...)
Note:
When the RECEIVER is moved
away from the TARGET CABLE
to the right, the signal phase
relationship between the two
antenna sets changes to a
NEGATIVE VALUE. .
POSITIVE
VALUE
? ? Directional Arrow - The
LEFT
arrow appears in the
display
meaning the
Receiver should
be moved to
the left.
? ? Audio Tone High, warbling
NEGATIVE
VALUE
RECEIVER
UPPER
ANTENNA SET
( Peak & Null Coils)
Location #3: Negative Value
? ? Bargraph - Opens up away
from
the center of the display.
? ? Numeric Indicator Lower
reading compared
to location
#1.
ZERO-VALUE
2
1
3
LOWER
ANTENNA SET
( Peak & Null Coils)
SOIL
TARGET CABLE
21
Cable Tracing - Differential Mode
DynatelTM 2273
Trace
Frequency
Fault/Tone
ON
Hz
OFF
Ref
Volume
Gain Adjust Depth/Current
22
CABLE TRACING - PEAK MODE
(in a congested environment)
Note:
In this mode, a flag appears below the
PEAK symbol over the LCD display.
DISPLAY INDICATIONS:
LOCATION #1:
When the RECEIVER is over the
TARGET CABLE
? Bargraph - moves closest towards
center of the display.
? Numeric Indicator - Higher
compared
to location #2.
? Audio Tone - Stronger
compared to
location #2.
LOCATION #2:
When RECEIVER is moved to the right
over the OTHER CABLE.
? Bargraph - Opens up and moves away
from center of display.
? Numeric Indicator - Lower than that of
location #1.
? Audio Tone - Weaker than that of
location #1.
BIG PEAK
SMALL PEAK
1
2
SOIL
OTHER CABLE
TARGET CABLE
23
CABLE TRACING - NULL MODE
CAUTION:
(in a congested environment)
In NULL mode, the concept is that the
Receiver will look for a ZERO
(NULL) condition or a point where
two or more opposing signals
cancel
out.
In congested areas, using NULL can lead
into what is commonly called a
GHOST CABLE situation.
This means that if there are other cables
which are close to the TARGET
CABLE, the RECEIVER can be
fooled by a “NULL” indication
which does not really represent the
true location of the cable.
NULL
TRACE
1
2
3
This happens when the signal from the
TARGET CABLE and the signal
from the OTHER CABLE meet in
some area between them and cancel
out (NULL), see illustration. This can
then be interpreted by the Receiver as
the location of the cable but actually
it is “not”.
Because of this problem, using NULL in
congested areas should be avoided.
If one has to use NULL in such
environments, it is strongly suggested
that cable location must always be
verified using PEAK mode.
OTHER CABLE
TARGET CABLE
GHOST CABLE
24
CABLE TRACING - NULL MODE
Note:
(IN A CONGESTED ENVIRONMENT - CON’T...)
In this mode, a flag appears below the
NULL symbol on top of the LCD
display.
DISPLAY INDICATIONS:
Location #1:
Receiver is over the TARGET
CABLE
? Bargraph - Opens up away from
center of display.
? Numeric Indicator - High
compared to location #2 &
#3.
? Audio Tone - Strong
compared to
location #2 & #3.
NULL
TRACE
1
2
3
Location #2:
Receiver is moved to the RIGHT
towards the OTHER CABLE and
NULLS
? Bargraph - moves closer
towards center of display.
? Numeric Indicator - reading goes
down and lower than in location
#1 & #3.
? Audio Tone - Level goes down
significantly compared to
location #1 & #3.
OTHER CABLE
TARGET CABLE
GHOST CABLE
25
CABLE TRACING - NULL MODE
(IN A CONGESTED ENVIRONMENT - CON’T...)
NULL
TRACE
DISPLAY INDICATIONS
(con’t ...)
Location #3:
Receiver is over the
OTHER CABLE
? Bargraph Opens up
away from
center of
display.
? Numeric
Indicator Higher
compared to
that of
location #2 but
lower
than in location
#1.
? Audio
Tone - stronger
than
that of location #2
but
weaker than that of
location #1.
1
2
3
SOIL
OTHER CABLE
TARGET CABLE
GHOST CABLE
26
CABLE TRACING - DIFFERENTIAL MODE
CAUTION:
(IN A CONGESTED ENVIRONMENT)
DIFFERENTIAL mode like
NULL has the same problem of
creating a GHOST CABLE situation
when used in congested areas.
If it is to be used in such environments, one has to verify cable
location by using PEAK mode,
always.
(+)
0
(-)
DISPLAY INDICATIONS:
1
2
3
LOCATION #1: Positive Value
(Receiver is over the TARGET
CABLE)
? ? Bargraph - Opens up and
moves
away from center of the
display.
? ? Numeric Indication Lower
compared to location
#2 but
higher than in location
#3.
? ? Directional Arrow - RIGHT
arrow will appear on
display. ? ? Audio Tone - Low and
warbling
SOIL
TARGET
CABLE
OTHER CABLE
GHOST CABLE
27
CABLE TRACING - DIFFERENTIAL MODE
(IN A CONGESTED ENVIRONMENT - con’t...)
DISPLAY INDICATIONS
(CON’T . . . )
LOCATION #2: - Zero-Value (GHOST
CABLE location)
? ? Bargraph - moves towards center of
display to max. closed indication.
? ? Numeric Indicator - Higher
compared
to location #1 & #3.
(+)
0
? ? Directional Arrows - Both LEFT &
RIGHT arrows will appear on
display.
? ? AudioTone - Solid (not warbling)
LOCATION #3: - Negative Signal
Value (Receiver is over the OTHER
CABLE)
? ? Bargraph - Opens up and moves
away from center of the display.
? ? Numeric Indicator - Lower than
that of
location #2 & #3.
? ? Directional Arrow - LEFT arrow
appears in display which means
the
RECEIVER should be moved to
the
left.
? ? Audio Tone - High and warbling
(-)
1
2
3
SOIL
TARGET
CABLE
OTHER CABLE
GHOST CABLE
28
SPECIAL PEAK MODE
(NORMAL VS. SPECIAL)
SHARP TRACE
NORMAL PEAK
UPPER
PEAK COIL
? Upper & Lower PEAK
antenna are activated.
? More accurate (much
sharper response).
? Less sensitive - used for
standard cable depths
LOWER
PEAK COIL
BROAD TRACE
SPECIAL PEAK
? Only Lower PEAK
antenna is activated.
? Less accurate (broad
response).
? Very sensitive - used
for weak signals such
as those from very deep
cables.
LOWER
PEAK COIL
SOIL
TARGET CABLE
TARGET CABLE
29
IDENTIFYING THE CORRECT CABLE
USING DEPTH AND CURRENT MEASUREMENT MODE
A: DISPLAY IN TRACE MODE
Note:
In A: TRACE mode, both Bargraph and
Numeric indications are based on signal
strength.
As shown in the illustration, the OTHER
CABLE being closer to the Receiver is
registering a higher relative signal strength
of 113 with the Bargraph moving more
closer to the center of the display.
1
On the other hand, the TARGET CABLE
because it is farther away from the Receiver
is only registering a lower relative signal
strength of 110 with the Bargraph opening
wider and moving away from the center of
the display.
In this case, it looks like the OTHER CABLE
is the correct cable but actually, it is not.
2
6 in
28 in
OTHER CABLE
TARGET
CABLE
30
IDENTIFYING THE CORRECT CABLE
USING DEPTH AND CURRENT MEASUREMENT MODE
A: DISPLAY IN TRACE MODE
B: DISPLAY IN DEPTH & CURRENT
MEASUREMENT MODE
in
in
Note:
In B: DEPTH & CURRENT measurement mode, the
NUMERIC indications are based on the magnitude of
the current flowing through the cables.
1
2
In position #1, the TARGET CABLE has a relative
CURRENT measurement of 94 at the depth of 27
inches. Take note that although the cable is deeper it is
giving a much higher current reading than in position
#2.
In POSITION #2, the OTHER CABLE has a relative
CURRENT measurement of only 46 even though the
cable is much less deeper and closer (only 5 in.) to the
Receiver.
The indications in the DEPTH & CURRENT
measurement mode will therefore positively identify
the correct cable.
6 in
28 in
OTHER CABLE
TARGET
CABLE
31
CABLE DEPTH AND CURRENT READOUTS
in
in
TYPICAL DEPTH & CURRENT READOUT
DEPTH
=
26 in.
CURRENT
=
94 (relative)
UNRELIABLE READING
DEPTH MEASUREMENT OPTIONS
1. INCHES
2. FEET AND INCHES
3. CENTIMETERS (cm)
32
TRACING RANGE
2200-SERIES CABLE LOCATORS
(Typical Conditions - Direct Connect With Far-End Of Cable Grounded)
FREQUENCIES
US MODEL
? 577 Hz
? 8 kHz
RANGE
EXPORT MODEL
577 Hz
49,000 feet (15 Km)
8 kHz
19,600 feet (6 Km)
? 33 kHz
33 kHz
9,800 feet (3 Km)
? 200 kHz
133 kHz
4,900 feet (1.5 Km)
33
TIPS IN SELECTING TRACE FREQUENCIES
? Audio frequencies (577Hz or 8kHz) can only be used if
the trace circuit resistance is 3000 ohms or less,
otherwise use the RF frequencies (33kHz, 133kHz, or
200kHz).
? Higher frequencies are much easier to induced into nearby
cables. To minimize induction of unwanted signals to
other cables in congested areas, use the lowest possible
trace frequency.
? If a CONTINUOUSLY GROUNDED conductor is used
for tracing (Ex: uninsulated outer “lead” sheath of a
Lead Cable), use DIRECT CONNECT METHOD and
the lowest possible trace frequency (577Hz).
34
TRANSMITTER HOOKUPS
1. DIRECT CONNECT METHOD
2. DYNACOUPLER METHOD
3. INDUCTION METHOD
35
DIRECT CONNECT METHOD
( ACCESSORIES USED )
2273 CONTROL PANEL
Dynatel
T M
2273
Trace
Off
On
Output Level
RED CLIP
DIRECT CONNECT
CABLE
BLACK CLIP
GROUND ROD
36
DIRECT CONNECT HOOKUP
RED CLIP
T2
T1
CABLE SHIELD
FAR-END
GROUND
CURRENT FLOW
TRANSMITTER
NEAR-END GROUND
REMOVED
GROUND
ROD
SOIL
SOIL
BLACK CLIP
CURRENT FLOW
1. Place the GROUND ROD into soil and connect the BLACK clip to it.
2. Remove the NEAR-END GROUND and connect the RED clip to the cable SHIELD.
3. Turn the unit ON in the OHMS function and check for any voltages that may exist on the cable shield. Check the circuit resistance to ground.
? ? If circuit resistance is 3000 ohms or less, a solid tone is emitted from the speaker. This means any or all of the trace frequencies can be
used.
Audio frequencies will have longer range and induced signal to other cables is minimal.If “ALL” is selected, set the transmitter to
“High output..
? ? If circuit resistance is between 3000 ohms to less than 10,000 ohms, an interrupted tone is emitted from the speaker. Use higher trace
frequencies (8kHz, or 33kHz or 200kHz). The transmitter can be set to “High” output.
? ? If circuit resistance is more than 3000 ohms but less than 10,000 ohms, an interrupted tone is emitted from the speaker. Use higher trace
frequencies (8kHz, or 33kHz or 200kHz). For stronger signal, set transmitter to “High” output.
37
DIRECT CONNECT HOOKUP
INNER
CONDUCTOR
RED
CLIP
CURRENT FLOW
FAR-END
GROUND
CABLE SHIELD
SOIL
TRANSMITTER
BLACK CLIP
GROUND
ROD
SOIL
CURRENT FLOW
38
DIRECT CONNECT HOOKUP
( DO’S & DON’TS )
OPEN-END
CABLE SHIELD
RED CLIP
DISTRIBUTED CABLE CAPACITANCE
C
C
C
C
C
C
C
TRANSMITTER
GROUND
ROD
SOIL
BLACK CLIP
CURRENT FLOW
1. If far-end of cable is open or not accessible for grounding - use the highest RF trace frequency, only.
Note:
This procedure is only applicable if length of cable is long enough (few hundred feet/meters)
to permit the highest RF CURRENT to flow through the accumulated distributed capacitance of the
cable.
39
DIRECT CONNECT HOOKUP
( DO’S & DON’TS - CON’T... )
SHORT CABLE
RED CLIP
SHORT CABLE
FAR-END
GROUND
TRANSMITTER
RED CLIP
FAR-END
WIRE
CONNECTION
TRANSMITTER
[A]
[B]
50 FEET (15 m)
CURRENT
FLOW
GROUND
ROD
BLACK CLIP
SOIL
BLACK CLIP
CURRENT FLOW
CURRENT RETURN WIRE
To trace very short lengths of cable, less than 100 feet (30 m):
? ? The far-end of the trace conductor must always be grounded to EARTH SOIL
(illustration A).
? ? If EARTH/SOIL is not accessible, a WIRE can be used as the current return path, but
it
must be placed 50 feet (15m) or more away from trace conductor (illustration B).
40
DYNA-COUPLER METHOD
( ACCESSORIES USED )
22273 CONTROL PANEL
Dynatel
T M
2273
Trace
Off
On
Output Level
DYNA-COUPLER
CABLE
DYNA-COUPLER
41
DYNA-COUPLER HOOKUP
T1
NEAR-END
GROUND
CABLE SHIELD
SECONDARY CURRENT FLOW
DYNA-COUPLER
T2
FAR-END
GROUND
SOIL
TRANSMITTER
PRIMARY
CURRENT
FLOW
SECONDARY CURRENT FLOW
NOTE:
? ? Do not remove NEAR-END and/or FAR-END GROUNDS. Doing so will
break or open the trace circuit and “no” current will flow.
? ? Only the frequencies (8kHz, 33kHz, 133kHz or 200kHz) will work with
the
Dyna-Coupler. 577Hz will “not”.
42
DYNA-COUPLER HOOKUP
[ DO’S AND DON’TS ]
GROUNDED
END
TRANSMITTER
DYNA-COUPLER
A
CABLE SHIELD
C
C
C
C
OPEN-END
C
C
DISTRIBUTED CABLE CAPACITANCE
SOIL
SECONDARY CURRENT FLOW
PRIMARY
CURRENT FLOW
TRANSMITTER
OPEN-END
B
CABLE SHIELD
DYNA-COUPLER
GROUNDED
END
SOIL
NO SECONDARY CURRENT FLOW
NOTE:
1. If one end of the cable is open or not accessible for grounding to SOIL, it is still possible to trace the cable if it is
long enough (several hundred feet/meters or more) to have the necessary accumulated distributed capacitance
which permits the highest trace frequency current to pass through ( ex: 133kHz or 200kHz ).
2. Also, the Dyna-coupler must always be placed close to the grounded end of the cable (illustration “A”).
3. Never place the Dyna-coupler at the un-grounded end of the cable (illustration B). It will not work. No secondary
current will flow.
43
INDUCTION METHOD & HOOKUP
ER
MITT
S
N
TRA
L
RNA IL
INTEMIT CO
NS
TRA
-END
FAR UND
GRO
LD
SHIE
E
L
B
CA
ARY
PRIMNT FLOW
RE
CUR
D
R -EN
NEAOUND
GR
L
SOI
FLOW
ENT
R
R
Y CU
DAR
N
O
SEC
Note:
?
?
?
?
To achieve best results, Transmitter must be placed over and as close as possible to the cable and should be in-line with cable path.
NEAR-END and FAR-END of the trace cable/conductor must be GROUNDED to SOIL to maintain continuity of the trace circuit.
Use the high frequencies 133kHz or 200kHz and switch Transmitter to high output.
Induction Method is not recommended in congested areas because the signal can be easily induced to other cables or pipes which is close and in
parallel to the target cable.
? Operate the Receiver no less than 50 feet (15 meters) from Transmitter to avoid direct reception of signal.
44
One Touch Gain Adjust
Just press once and you’ve got it...
No need for multiple key presses…
No Guessing…
No Trial & Error...
PEAK
PEAK
Ref
Gain Adjust
If signal is too weak.
Reference Gain Level
PEAK
PEAK
Ref
Gain Adjust
If signal is too strong.
Reference Gain Level
45
EARTH RETURN (SHEATH) FAULT LOCATE - BASIC THEORY
TRANSMITTER
CURRENT FLOW
VOLTAGE
GRADIENT
VOLTAGE
GRADIENT
Off
CABLE SHIELD
GROUND ROD
BLACK CLIP
RED CLIP
GROUNDING
REMOVED
GROUNDING
REMOVED
SOIL
CURRENT FLOW
NOTE:
? ? In FAULT-LOCATE, the Transmitter forces current to flow through the FAULT/S. It is important that current
flow
must be concentrated into the FAULT/S only. To do this, all GROUND or SOIL connections to the trace
cable
or conductor must be temporarily disconnected.
? ? As the CURRENT enters the SOIL, it creates a VOLTAGE GRADIENT (slope) on the SOIL’s surface (see
illustration on next page).
? ? For best results, the GROUND ROD should be placed into the SOIL, in-line with the cable path.
46
EARTH RETURN (SHEATH) FAULT LOCATE - BASIC THEORY
[ CON’T... ]
Dynatel
TM
2273
Dynatel
Location #1:
Red Leg = +3V
Green Leg = +6V
Bargraph at Green Move forward
1
Location #2:
Red Leg = +7V
Green Leg = +7V
Bargraph floats - NULL
Stop - Fault located
Location #3:
Red Leg = +6V
Green Leg = +3V
Bargraph at Red - Move
back.
R
E
D
TM
2273
2
Dynatel
G
R
N
A- FRAME
+2
+3
+4
+5
2273
3
A- FRAME
+6 +7 +8
+9
+8 +7 +6
SOIL RESISTANCE
CURRENT FLOW
TM
+5
+4
+3
+2
SOIL RESISTANCE
FAULT
CURRENT FLOW
FROM TRANSMITTER
NOTE:
? ? As the CURRENT enters the SOIL, a VOLTAGE GRADIENT (slope) is created on the soil’s surface.
The A-FRAME is then plugged into the Receiver and it is used to sense voltage potentials along the cable path.
The A-FRAME has two probe tips, one is marked RED and the other is GREEN.
? ? The goal here is to determine when the RED and GREEN tips senses a NULL , a condition where the voltage
potentials at the RED and GREEN tips are the same or zero).
? ? Once NULL is achieved, the center of the A-FRAME will then represent the location of the FAULT
(position #2).
47
MULTIPLE EARTH RETURN (SHEATH) FAULT LOCATE
Dynatel T M 2273
Dynatel T M 2273
Dynatel T M 2273
R
G
R
G
R
G
E
R
E
R
E
R
N
D
N
D
D
1
2
VOLTAGE
GRADIENT
VOLTAGE
GRADIENT
TRANSMITTER
3
N
VOLTAGE
GRADIENT
CABLE SHIELD
MINOR FAULT
MAJOR FAULT
Off
CURRENT FLOW
NOTE:
? ? A reference must be established by placing the A-FRAME one pace away from the GROUND
ROD
(position #1).
? ? Take a reading and press the GAIN/REF ADJUST key to store reference into memory.
Position #1Reading
=
124 (Reference)
Position #2 Reading
=
118 (Major Fault)
Position #3 Reading
=
90 (Minor Fault)
48
2200 SERIES CABLE / EARTH RETURN
(SHEATH) FAULT LOCATORS
OPTIONAL
ACCESSORIES
49
ACCESSORIES
(CON’T..)
Alert
33 kHz
PWR
577 Hz
Dynatel T M
2205
Batt Test
Off
2200
RECEIVER
2205
DEDICATED
2205
EMS MARKER LOCATOR
TOP VIEW
PWR
Alert
33 kHz
577 Hz
Batt Test
Off
Dynatel
2205
TM
50
ACCESSORIES
(CON’T..)
CT
2200
Pwr
Alert
Wtr
33 kHz
WWtr
577 Hz
Tel
Gas
Batt Test
Dynatel T M
2206
Off
RECEIVER
2206
2206
EMS ALL-MARKER
LOCATOR
TOP VIEW
Pwr
Wtr
WWt
r
Tel
Gas
CT
Alert
33 kHz
577 Hz
Batt Test
Off
T M
Dynatel
2206
51
ELECTRONIC MARKER SYSTEM ( E M S )
TONE
Basic Theory:
2200
RECEIVER
1. Initially , the 2205 / 2206 unit is turned ON in
TRANSMIT mode, transmitting a signal to
the
MARKER.
2. The MARKER in return, absorbs and stores the
received signal energy from the 2205 /2206.
3. After the TRANSMIT phase, the 2205 / 2206 unit
switches to RECEIVE mode and then the stored
energy in the MARKER starts to discharge.
2205
2206
4. As the signal energy discharges, the MARKER acts as
a TRANSMITTER and starts transmitting the
signal back to the 2205 / 2206.
5. Once the 2205 / 2206 unit detects the incoming signal
from the MARKER, the 2200 RECEIVER emits a
continuous audible TONE.
The TONE is strongest when the 2205 / 2206 is
exactly over the MARKER. Also, the
BARGRAPH will move towards the center of the
display and indicate its maximum closed position.
6. The cycle is then repeated over and over again until
the 2205 / 2206 unit is turned OFF.
2205
2206
SOIL
SOIL
2205/2206
SIGNAL
MARKER
SIGNAL
BALL
MARKER
CABLE SPLICE
BALL
MARKER
CABLE SPLICE
52
ACCESSORIES
(CON’T..)
33 kHz RF Signal
SCOTCHMARK ADP
ACTIVE DUCT PROBE ( SONDE )
53
ACTIVE DUCT PROBE (SONDE)
THE APPLICATION:
LOCATING BLOCKAGES OR OBSTRUCTIONS INSIDE
PLASTIC DUCTS AND CONDUITS
2200
RECEIVER
2200
RECEIVER
NOTE:
THE ADP SIGNAL MUST BE TRACED IN PEAK
MODE. TO DO THIS, THE 2200 RECEIVER SHOULD
BE POSITIONED PERPENDICULAR TO THE ADP.
33 kHz
SIGNAL
33 kHz
SIGNAL
PLASTIC PIPE
DENT
PLASTIC PIPE
54
Cable & Pipe Locating Techniques
Dynatel 2200-Series Cable/Fault Locators
55
Locating Non-metallic Pipe
Heavy gauge wire
Fish tape or Snake
2250 or 2273
Ground Rod
Signal Return Path
Transmitter
Non-metallic pipe
Earth/Soil
Signal
Wire’s distributed
capacitance to earth/soil
Note:
One end of pipe must be accessible. Push a heavy gauge wire, snake or fish tape into the
pipe. Because the signal current must pass through the wire’s distributed capacitance to
earth/soil, use any of these frequencies (8 kHz, 33 kHz or 200 kHz). Also, set transmitter to
‘HIGH” output, if a stronger signal is required.
56
Applying Signal To A Pipe
[Dyna-Coupler Method]
Screwdriver
Screwdriver
Earth Ground
Earth Ground
Dyna-Coupler
Signal
1
Signal
2
3
Earth Soil
Note:
With the Dyna-Coupler, you can use any of these frequencies (8 kHz, 33kHz or 200kHz)
and set the Transmitter to “High” output.
If both far-ends of a pipe section can be or are grounded. The Dyna-Coupler can be
placed in any location (1, 2 or 3) along the pipe section.
57
Applying Signal To Pipe And Controlling Signal Direction
[Dyna-Coupler Method]
Screwdriver
Earth Ground
Signal
Earth/Soil
Insulated Pipe
Note:
With the Dyna-Coupler, you can use any of these frequencies (8 kHz, 33kHz or 200kHz) and
set the Transmitter to “HIGH” output.
If the Dyna-Coupler is placed to the right of the Earth Ground, the signal goes to the right.
If the pipe’s far-end to the right is “NOT” grounded, the Dyna-Coupler must be placed as
close as possible to the location of the Earth Ground.
58
Applying Signal To Pipe And Controlling Signal Direction
[Dyna-Coupler Method]
Screwdriver
Earth Ground
Dyna-Coupler
Signal
Insulated Pipe
Earth/Soil
Note:
With the Dyna-Coupler, you can use any of these frequencies (8 kHz, 33kHz or 200kHz) and
set the Transmitter to “HIGH” output.
If the Dyna-Coupler is placed to the left of the Earth Ground, the signal goes to the left.
If the pipe’s far-end to the left is “NOT” grounded, the Dyna-Coupler must be placed as
close as possible to the location of the Earth Ground.
59
Applying Signal to Pipe
[Dyna-Coupler Method]
Note:
With the Dyna-Coupler, you can
use any of these trace frequencies
(8 kHz, 33kHz or 200kHz) and set
the Transmitter to “HIGH”
output.
eter
Gas M
Ground Rod
In this illustration, the far-end may
or may not be grounded. It works
either way.
2250 or 2273
Signal Current
Return Path
Transmitter
M
eta
llic
Se
rv
ice
Li
ne
(in
su
lat
ed
)
60
Applying Signal To Primary Cables
[Dyna-Coupler Method]
Note:
Use Dyna-Coupler to put trace signal
to energized primary cables.
Three-Phase Primary Elbows
Where the Dyna-Coupler is clamped is
very important.On three-phase
primary cables, the Dyna-Coupler
should be clamped on all concentric
neutrals and as close as possible to
earth ground.With this setup, the
signal is coupled onto each cable
equally.
Use any one of these trace frequencies
(8 kHz 33kHz or 200kHz) and set the
Transmitter to “HIGH” output.
Signal
Concentric
Neutrals
Signal
Signal
Signal
Note (con’t):
Dyna-Coupler
Do not place the Dyna-Coupler on any individual
concentric neutral.
Since the cables are buried in the same trench, the signal
goes one way on one cable and comes back the opposite
way on the other two. This causes signal cancellation.
Earth Ground
Signal Current
Return Path
61
Applying Signal To Primary Cables
[DynaDyna-Coupler Method]
Single-Phase Primary Elbows
OUT
IN
Signal
Signal
Dyna-Coupler
Note:
Concentric
Neutrals
On single-phase primary cables used in a loop
configuration, signal cancellation is not a problem.
The signal can be applied with the Dyna-Coupler to the
individual concentric neutral of the cable.
Earth Ground
Signal Current
Return Path
62
Applying Signal To Tracer Wires
[Direct[Direct-Connect Method]
Note:
For best results, ground the far-end and check the
circuit resistance to ground using the built-in
ohmmeter.
r
Mete
Gas
Ground Rod
Signal Current
Return Path
Transmitter
No
n-
me
tal
lic
Gas
No
n-
Sig
na
l
pip
e
Se
rv
ice
al
Sign
Tr
ac
er
W
ire
If resistance to ground is 3000 ohms or less, use the
lowest trace frequency (577Hz). If it is more than
3000 ohms but less than 10K ohms, you can use
8kHz. If it is 10K ohms or higher, use 33kHz or
200kHz.
r
Mete
me
tal
lic
Twisted
pip
e
Non-Electrical
Connection
ire
cer W
a
r
T
Main
ain
llic M
a
t
e
m
Non-
Far-end
Earth Ground
l
Signa
ction
onne
C
l
a
ric
Elect
63
Applying Signal To Tracer Wires
[Direct[Direct-Connect Method]
eter
Gas M
Note:
Gas
r
Mete
If both far-ends of the pipe are
grounded, the signal will divide
towards each end.
For best results, use 577Hz or
8kHz.
Ground Rod
ent
l Curr
a
n
g
i
S
n Path
Retur
Transmitter
No
n-
me
tal
lic
Sig
na
l
pip
e
l
Signa
Far-end
Earth Ground
Se
rv
ice
No
n-
me
tal
lic
Twisted
pip
e
Non-Electrical
Connection
er
Trac
Main ire
W
Tr
ac
er
W
ire
50%
50%
l
Signa
nd
Far-e und
Gro
Earth
ion
nnect
o
C
n
i
l
a
rica
llic M
Elect
meta
n
o
N
64
Applying Signal To Tracer Wires
[Direct[Direct-Connect Method]
eter
Gas M
Note:
r
Mete
Gas
If far-end ground #1 is removed, signal flows
towards far-end ground #2.
Measure circuit resistance to ground. If it is
3000 ohms or less, use 577Hz. If it is more than
3000 ohms but less than 10k ohms, use 8kHz. If
it higher than 10K ohms, use 33kHz or 200kHz
Ground Rod
2250 / 2273
ent
l Curr
Signa n Path
Retur
Transmitter
No
n-
me
tal
lic
pip
e
Sig
na
l
d #1
roun
G
d)
-end
Far remove
(
Se
rv
ice
No
n-
Tr
ac
er
W
ire
me
tal
lic
pip
e
Twisted
Non-Electrical
Connection
er
Trac
n
i
a
M
Wire
#2
round
G
d
n
Far-e
l
Signa
ction
onne
C
n
i
l
a
a
ric
llic M
Elect
meta
Non-
65
Applying Signal To Tracer Wires
[Direct-Connect Method]
eter
Gas M
r
Mete
Gas
Note:
If the RF frequencies (33kHz or
200kHz) are used in this illustration, all
the trace wires will carry the signal
through both direct and capacitive
coupling.
Ground Rod
2250 / 2273
ent
l Curr
Signa
a
n P th
Retur
Transmitter
No
n-
me
tal
lic
Sig
na
l
pip
e
l
Signa
Se
rv
ice
No
n-
me
tal
lic
Tr
ac
er
W
ire
Twisted
pip
e
Non-Electrical
Connection
er
Trac
Main ire
W
l
Signa
Far-end Ground
ection
Conn
in
l
a
a
c
M
i
r
llic
Elect
meta
Non-
66