Metrel MI2093 Linetracer

Introduction

The Metrel MI2093 Linetracer is a universal instrument designed for tracing hidden conductive paths within walls, floors, and underground, or for identifying a specific wire within a bundle. It can also locate fuses and outlets associated with a particular circuit, helping users resolve common line problems such as short-circuits or interruptions efficiently.

The instrument features a 10-level LED bargraph indicator and a buzzer to provide feedback on the received signal strength. The receiver offers three sensitivity levels and a potentiometer for fine-tuning sensitivity to achieve an optimal signal.

The T10K transmitter automatically selects its operating mode (load or generator) based on whether the tested location is energized or unenergized. It functions as an active signal generator for DC-powered or unenergized lines and as a pulsating electric load for energized lines (30V – 264V, 50/60Hz AC). In both modes, a 10.6 kHz signal is injected into the conductor.

Accessories such as test leads for direct connection to the conductor and voltage/current clamps further enhance the Linetracer's functionality. The instrument is supplied with all necessary accessories for testing, conveniently stored in a soft carrying bag.

The majority of electronic components are manufactured using SMD technology, minimizing the need for service interventions.

Applied Standards

• Safety: EN/IEC 61010-1 (Instrument), EN/IEC 61010-2-31 (Accessories)
• EMC: EN/IEC 61326

Fields of Use

While primarily intended for electrical installations, the Line Tracer is also a valuable tool for telecommunications, data network installations, and similar applications. Key activities include:

• Tracing cables in walls, ceilings, floors, and underground.
• Locating both live and voltage-free cables.
• Identifying cable interruptions and short-circuits.
• Finding concealed sockets and distribution boxes.
• Locating fuses and assigning them to specific circuits.
• Determining individual wires within a cable bundle.
• Tracing metal pipes and other conductive materials.

Transmitter T10K

The T10K transmitter functions as a signal generator when connected to unenergized or DC-powered conductors. If the AC line voltage exceeds 30V, it automatically switches to a pulsating load function. The injected signal (voltage or current) operates at 10.6kHz, modulated with 4Hz. For tracing closed metal loops (e.g., pipe systems), a generator clamp (Metrel A1019) can be used to inject the signal.

Figure 1: Transmitter T10K depicts the device, showing its LED indicators (Generator, Load, Low Battery), output terminals, and the ON/OFF switch. The transmitter is powered by four AA type 1.5V batteries.

Receiver R10K

The highly sensitive R10K receiver detects injected signals around a measured line. It can detect electromagnetic signals using the INDUCTIVE mode or electrostatic signals using the CAPACITIVE mode. A switch allows selection between these modes. Three sensitivity levels (low, medium, high) are available, along with an additional potentiometer for fine adjustment. Signal indication is provided via a buzzer and a 10-level LED bar graph. The receiver is powered by a single 9V battery (IEC 6LR61).

Figure 2: Receiver R10K illustrates the receiver, highlighting features such as the Low Battery indicator, Sound opening, ON/GAIN keys, Sensitive area, Inductive/Capacitive switch, LED bargraph, Power ON LED indicator, Potentiometer for fine adjustment, and Input connector (for probe/current clamp).

Theory of Operation

Tracing Electrical Field in Lines

When connected to an unenergized or DC-powered line, the T10K transmitter acts as an active voltage generator, applying voltage between the conductor and ground. The resulting electrical field is detected by the R10K receiver in CAPACITIVE mode. Sensitivity can be enhanced by positioning the receiver close to the conductor and ensuring the operator is well-grounded (e.g., by touching grounded metal). For optimal signal reception, the traced line should be insulated from ground, and switches/loads should be turned off to prevent signal attenuation.

Figure 3: Tracing electrical field of the line shows the T10K transmitter connected to an unenergized line, with the R10K receiver in CAPACITIVE mode detecting the electrical field.

Tracing

When a traced line or part of it is accessible, using an appropriate test tip connected to the R10K receiver (as shown in Figure 4) is recommended. This improves signal selectivity, aiding applications like fuse identification or tracing individual wires in a bundle. Using the LOW sensitivity setting is advised for these tasks.

Figure 4: Tracing of line using Test tip illustrates the T10K transmitter in generator mode connected to an unenergized line, with the R10K receiver using a test tip in CAPACITIVE mode.

Tracing Electromagnetic Fields of Lines

The T10K transmitter operates as a current generator for unenergized or DC-powered lines, or as a pulsating load for AC-energized lines. It can be connected between two lines, a line and ground, or to a pipe installation loop. The electromagnetic field generated by the injected current is detected by the R10K receiver's inductive sensor. Proper positioning of the receiver is crucial for accurate detection and determining wire direction.

Figure 5: Detection of electromagnetic field shows the principle of detecting an electromagnetic field, with the R10K receiver positioned correctly.

Transmitter as Current Generator (Generator Mode): When traced lines are in a closed circuit, the test current flows through the loop, which can occur with cable shorts or connected loads.

Figure 6: Injection of test current into tested loop illustrates this scenario with the T10K in generator mode and the R10K in inductive mode.

For tracing conductive loops like pipe installations where disconnection is difficult, a current clamp can be used to inject the test signal.

Figure 7: Injection of test current into closed tested loop by means of current clamp shows this method.

b) Transmitter as Pulsating Load: In this mode, the loop is determined by the mains transformer. This method yields the best results and selectivity due to high injected current values, allowing for accurate tracing over longer distances.

Figure 8: Transmitter as active load shows the T10K in load mode connected to the mains supply, with the R10K in inductive mode.

Tracing by Means of Current Clamp: When possible, using an appropriate current clamp instead of the receiver's inductive sensor significantly improves signal selectivity.

Figure 9: Transmitter as active load, clamp used instead of inductive sensor demonstrates this improved method.

Typical Applications

Tracing Cables in Walls, Ceilings, Floor and Ground, and Detecting Fuses

Tracing of Hidden Wires on Unenergized Systems:

Figure 10: Tracing cable or determination of belonging fuse on unenergized installation. illustrates tracing a cable or identifying a fuse in an unenergized system. The receiver detects the electrical field generated by the transmitter.

Tracing Cables in Walls, Ceilings, Floor and Ground on Energized Systems:

Figure 11: Tracing cable or determination of belonging fuse on energized installation. shows tracing a cable or identifying a fuse in an energized system. The receiver detects the electromagnetic field generated by the load current from the transmitter.

Determining Cable Faults

Location of Cable Interruptions:

Figure 12: Determination of interruption location. The electrical field caused by the transmitter disappears behind the interruption point.

Locating of Earth Fault (Short Circuit):

Figure 13: Determination of short circuit location. The electromagnetic field disappears behind the short circuit location. Attention: The transmitter's load current is 1A. For safety reasons, the maximum value of RE (earth resistance) should be less than 50 ohms.

Determining Individual Wires, Fuses etc.

Using Special Test Tip:

Figure 14: Determination of individual wire. The test tip connected to the receiver is used to identify individual wires. The LOW gain setting is recommended for this purpose.

Using Special Current Clamp:

Figure 15: Determination of belonging fuse by using current clamp. A current clamp can be used for precise identification of individual wires or fuses. The LOW gain setting is also recommended here.

Using Current Clamp for Current-Signal Injection:

Figure 16: Tracing conductive loops by using current clamp. Instead of direct current-signal injection, a clamp can be used to inject the signal, allowing conductive loops to be traced afterward.

Technical Characteristics

Transmitter T10K

• Batteries: 4 x AA size (1.5 V)
• Low battery indicator: Built-in
• Operating temperature: 0 – 40 °C
• Storage temperature: -30 – 60 °C
• Weight: 280 g
• Housing: ABS plastics
• Dimensions: 80 mm x 50 mm x 150 mm

The transmitter automatically switches between generator and load modes based on the input voltage.

Transmitter T10K in Generator Mode

• DC, AC voltage: < 30 V or no voltage present on line
• Operating frequency: 10.6 KHz modulated with 4 Hz
• Maximal open circuit voltage: 6 V eff.
• Maximal short circuit current: 20 mA eff.

Transmitter T10K in Load Mode

• Mains supply voltage necessary for transmitting: 30 ÷ 300 VAC
• Frequency of supply voltage: 45 ÷ 65 Hz
• Operating frequency: 10.6 KHz modulated with 4 Hz
• Maximal average injected current: 1 A eff.

Receiver R10K

• Battery: 1 x PP3 size (9 V)
• Low battery indicator: Built-in
• Operating temperature: 0 – 40 °C
• Storage temperature: -30 – 60 °C
• Weight: 140 g
• Housing: ABS plastics
• Dimensions: 45 mm x 45 mm x 210 mm

Features a built-in mechanical switch to select between capacitive and inductive modes.

• Sensor: Built-in capacitive sensor for capacitive mode and coil for inductive mode.
• Selectivity: Input band-pass filter 10.6 KHz.
• Indicators: Audio - piezoelectric speaker (70 dB); Visual - 10 level LED bargraph-style indicator.
• Sensitivity: LOW, MIDDLE, HIGH sensitivity keys, potentiometer for fine adjustment of signal gain.

Maintenance

Battery Replacement for Transmitter T10K

• Disconnect all test leads before opening the casing.
• Unscrew all four screws on the bottom of the casing. Remove the cover.
• Replace the batteries, paying attention to correct battery polarity.
• Fix the cover with all four screws to the original position.

Battery Replacement for Receiver R10K

• Unscrew two screws on the bottom of the casing. Remove the cover.
• Replace the battery, paying attention to correct battery polarity.
• Fix the cover with the two screws to the original position.

Cleaning

Use a soft cloth moistened with water or alcohol. Ensure the instrument dries completely before use. Do not use petroleum-based liquids or spill cleaning liquid onto the instrument.

Service

For any instrument malfunction or damage to the instrument or test leads, servicing must be performed by a competent service department. Contact your dealer for detailed information.

Ordering Information

Standard Set MI2093

• Transmitter T10K
• Receiver R10K
• Two test leads (safety banana on both sides), black, 1.5m (for T10K)
• Test tips, 2 pcs
• Alligator clips, 2 pcs
• Small soft carrying bag

Options

• Current clamp 1000A/1A, d = 52mm ........................................... A 1019
• Test lead, 1.5m, with built-in resistor, (for R10K) ......................... A 1067
• Connection cable for clamp ......................................................... A 1068
• Current clamp 200A/0.2A, d = 15mm .......................................... A 1069