UNI-T UT593/UT595 Multifunction Safety Tester Operating Manual

I. Overview

The UT593/UT595 is a multifunction digital safety testing instrument, designed with a combination of large-scale integrated analog & digital circuits and a microprocessor chip. It mainly measures RCD, line/loop impedance, continuity, insulation resistance, DC and AC voltage, and phase sequence, featuring versatile functionality, higher accuracy, stable performance, and ease of use. The instrument is widely used to measure RCD, insulation, and earth connections for various equipment, serving as an ideal tool for testing, inspection, and maintenance of electric devices and RCDs.

II. Safety Information

The Tester is designed, manufactured, and tested according to the IEC61010 safety standard. This manual includes safety information related to the safe use of the Tester. Please strictly follow the safety items and read the following instructions before use.

• [Danger] Specifies conditions and actions that may cause severe or fatal hazards.
• [Warning] Alerts users to avoid electric shock.
• [Caution] Specifies conditions and actions that may damage the Tester or affect accurate measurement.

[Danger]

• Do not measure around any flammable or sparkling areas as it may cause potential explosion.
• Do not operate the Tester if its surface is wet or the operator's hands are wet.
• Do not touch conductive parts of test leads during measurement.
• Do not measure with the battery cover opened.
• Do not touch the circuits under test when measuring insulation resistance and RCD.

[Warning]

• Stop using the Tester if any anomaly happens, if it is damaged, or shows exposed metal.
• Take extreme caution when working with voltages higher than 600Vrms AC or 1000VDC, as it may pose an electric shock hazard.
• The electric storage present in tested circuits must be released after finishing high resistance measurement.
• Do not replace the battery if the Tester is in a wet status.
• Make sure all test leads are firmly secured to input terminals of the Tester.
• Turn off the Tester before opening the battery cover.

[Caution]

• If it is necessary to replace test leads or power adapter, use only the same model with the same electrical specifications.
• When the low battery indicator [Low Battery Symbol] shows, do not use the Tester. Remove the battery if not used for a long time.
• Do not store or use the Tester around high temperature, high humidity, flammable, explosive, and electromagnetic environments.
• Clean the Tester's casing with a soft cloth dampened with water or mild detergent. No abrasives or solvents are allowed.
• Dry the Tester before storing it if it is wet.

III. Electrical Symbols

• Danger of possible electric shock
• Double insulation or reinforced insulation
• (DC)
• (AC)
• [Ground Symbol]

VI. Technical Specifications

V. Tester Description

The instrument features a large LCD display, function buttons (F1, F2, F3, F4), a TEST button, and a rotary switch. It also has input terminals for test leads (red, black, green).

Understanding F1-F4 Buttons:

• F1: Buzzer and backlight control. Long press F1 for about 2 seconds to turn on/off the backlight; short press to turn on/off the buzzer.
• F2: Test lock function. Press to turn on/off TEST LOCKED function. When it is necessary to take a long-time measurement, press F2 to enable the function; a lock indicator shows on LCD. You then just need to press TEST; do not release it, and the Tester will take measurements continuously. Press TEST again to stop the measurements. To disable the function, press F2 again or turn the rotary switch to other functions.
• F3: Zero function for test leads. First short-circuit two test leads, and then long press F3. The display will show "ZERO" indicating the operation completes.
• F4: Invalid (or specific function if applicable).

Rotary Switch Functions:

1. Phase Rotation: Detect Phase sequence
2. Volts: Measure Voltage/Frequency
3. 250V: Measure Insulation Resistance
4. 500V: Measure Insulation Resistance
5. 1000V: Measure Insulation Resistance
6. Continuity: Test continuity with Test Current up to 200mA
7. OFF
8. Loop/PSC/Zs/Ze: Measure Loop/Line Impedance, Prospective Fault Current, Prospective Short Current.
9. Auto: Automatically Test RCD
10. RCD Test (1/2*IΔn): Measure RCD Trip Time at 1/2 Rated Current
11. RCD Test (1*IΔn): Measure RCD Trip Time at Rated Current
12. RCD Test (2*IΔn): Measure RCD Trip Time at 2* Rated Current (UT595 only)
13. RCD Test (5*IΔn): Measure RCD Trip Time at 5* Rated Current
14. Ramp: Measure RCD Trip Current

VII. Preparations before Measurement

Low Battery Indicator: If the low battery indicator [Low Battery Symbol] shows on the upper left part of the LCD after turning on the Tester, it indicates the battery is low. Please replace the battery promptly.

VIII. Testing for Continuity (See Figure 3)

Figure 3 Description: Connect the red test lead to the red input terminal and the black test lead to the black terminal. Connect the probes to the circuit under test.

To test for continuity:

1. Discharge totally the tested circuits and keep them completely separated from the power supply before test.
2. Insert red lead (marked TEST) into red input terminal and black test lead to black terminal.
3. Connect red and black alligator clips or probes to the circuit under test.
4. Turn the rotary switch to continuity position, then press TEST button to begin. Refer to Figure 3 for details.

Understanding F1-F4 Buttons:

• F1: Long press F1 for about 2 seconds to turn on/off the backlight; short press to turn on/off the buzzer. The buzzer will alarm if the measured resistance is < 50Ω.
• F2: Test Lock function. Press to turn on/off TEST LOCKED function. When it is necessary to take a long-time measurement, press F2 to enable the function; a lock indicator shows on LCD. You then just need to press TEST; do not release it, and the Tester will take measurements continuously. Press TEST again to stop the measurements. To disable the function, press F2 again or turn the rotary switch to other functions.
• F3: Zero test leads. First short-circuit two test leads, and then long press F3. The display will show "ZERO" indicating the operation completes.

[Caution] Ensure circuit is de-energized before measurement. Do not test on live objects. Before the test starts, the Tester will automatically display the voltage between two input terminals if this voltage is > 30V, and the TEST button will be inhibited.

IX. Measuring Insulation Resistance (See Figure 4)

Figure 4 Description: Connect the red test lead to the red input terminal and the black test lead to the black terminal. Connect the probes to the circuit under test, ensuring it is de-energized.

To measure insulation resistance:

1. Discharge totally the tested circuits and keep them completely separated from the power supply before test.
2. Insert red lead (marked TEST) into red input terminal and black test lead to black terminal.
3. Connect red and black alligator clips or probes to the circuit under test.
4. Turn the rotary switch to Insulation position (250V, 500V, or 1000V) and select proper test voltage, then press TEST button to start.

Understanding F1-F4 Buttons:

• F1: Long press F1 for about 2 seconds to turn on/off the backlight.
• F2: Test Lock function. Press to turn on/off TEST LOCKED function. When it is necessary to take a long-time measurement, press F2 to enable the function; a lock indicator shows on LCD. You then just need to press TEST; do not release it, and the Tester will take measurements continuously. Press TEST again to stop the measurements. To disable the function, press F2 again or turn the rotary switch to other functions.
• F3: Invalid.
• F4: Invalid.

[Caution] Make sure the test circuits are de-energized before measurement. Do not measure any live electrical devices or lines. Before the test starts, the Tester will automatically display the voltage between two input terminals if this voltage is > 30V, and the TEST button will be inhibited. Do not measure with the battery cover opened. Do not short circuit two test leads under high voltage output status or measure insulation resistance after the high-voltage has already been output.

X. Measuring Voltage/Frequency (See Figure 5)

Figure 5 Description: Connect the red test lead to the red input terminal and the black test lead to the black terminal. Connect the probes to the circuit under test.

OR

Insert the three connectors of specified one-plug test leads to three input terminals of the Tester (red to red, green to green, black to black). Insert the plug of the test leads into the socket of test circuits.

To measure voltage/frequency:

1. Set the rotary switch to Volts.
2. Connect as shown in Figure 5.
3. Connect red & black alligator clips or probes firmly to tested circuits. The Tester will automatically identify AC/DC voltage and show measured voltage and frequency readings on the LCD.

Understanding F1-F4 Buttons:

• F1: Long press F1 for 2 seconds to turn on/off the backlight.
• F2, F3, F4: all are invalid. TEST is invalid too.

[Caution] Do not input voltage higher than 900V AC or 1000V DC. It may be possible to display the voltage value, but it may pose hazard to the Tester. To avoid electric shock, please take extreme caution when working with high voltage. Remove the test leads away from tested circuits and disconnect them from the input terminals of the Tester after completing the measurements. Do not measure with the battery cover opened.

XI. Detecting Phase Sequence (See Figure 6)

Figure 6 Description: Connect the three test leads (red, green, black) to the L1, L2, and L3 terminals of the three-phase AC system respectively. The instrument uses specific terminal assignments: black to L1, green to L2, red to L3 for forward rotation indication.

To Detect Phase Sequence:

1. Turn the rotary switch to Phase Rotation position.
2. Insert three connectors of three test leads into input terminals of the Tester (red to red, green to green, black to black).
3. Connect the three test leads into the three-phase AC system (black to L1, green to L2, red to L3, refer to Figure 6 for details), after that, the Tester will indicate the phase sequence and open phase result on LCD.

Understanding F1-F4 Buttons:

• F1: Long press for 2 seconds to turn on/off the backlight.
• F2, F3, F4: all are invalid; TEST button is invalid too.

[Caution] Do not input voltage higher than 440V AC. It may be possible to display the voltage value, but it may pose hazard to the Tester. To avoid electric shock, please take extreme caution when working with high voltage. Remove the test leads away from tested circuits and disconnect them from the input terminals of the Tester after completing the measurements. Do not measure with the battery cover opened.

XII. Measuring Loop Impedance/Prospective Fault Current (See Figure 7, 8)

Figure 7 & 8 Description: Connect the test leads to a power socket or the tested lines. For socket testing, use the plug-in lead. For line testing, use separate leads.

To measure Loop Impedance/ Prospective Fault Current:

1. Turn the rotary switch to LOOP.
2. Insert three connectors of one-plug test leads or three separate test leads into the three input terminals of the Tester (red to red, green to green, black to black).
3. Plug the plug into domestic 220V socket or connect the test probes to the tested lines.
4. Press TEST button to start.

Understanding F1-F4 Buttons:

• F1: Long press F1 for 2 seconds to turn on/off the backlight.
• F2, F3, F4: all are invalid.

[Caution] Please make sure domestic 220V in the power socket is normally supplied. If the socket is unable to be powered normally or de-energized, LPE and LN icons on lower left part of LCD will flash simultaneously. Ensure the socket is properly grounded. If the socket has bad grounding or isn't grounded, LPE and NPE icons on lower left part of LCD will flash simultaneously. Ensure the neutral terminal of the socket is firmly connected. If the neutral terminal is badly or not connected, LN and NPE icons on lower left part of LCD will flash simultaneously. Ensure live and neutral terminals of the power socket are not reversely connected when measuring loop impedance/prospective fault current, otherwise LPE, LN and NPE icons on the lower left part of LCD will flash simultaneously. Please take extreme caution when making the measurement for it is performed under high-voltage status.

XIII. Measuring Line Impedance/Prospective Short Current (See Figure 7, 8, 9)

Figure 7, 8, 9 Description: Connect the test leads to a power socket or the tested lines. For socket testing, use the plug-in lead. For line testing, use separate leads.

To measure Line Impedance/Prospective Short Current:

1. Turn the rotary switch to the Loop/PSC/Zs/Ze position.
2. Insert three connectors of one-plug test leads or three separate test leads into the three input terminals of the Tester (red to red, green to green, black to black). Refer to Figure 7.
3. Plug the plug into domestic 220V socket or connect the test probes to the tested lines.
4. Press TEST button to start.

Understanding F1-F4 Buttons:

• F1: Long press F1 for 2 seconds to turn on/off the backlight; short press to switch between L-N and L-PE measurements.
• F2, F3, F4: all are invalid.

[Caution] Please make sure domestic 220V in the power socket is normally supplied. If the socket is unable to be powered normally or de-energized, LPE and LN icons on lower left part of LCD will flash simultaneously. Ensure the socket is properly grounded. If the socket has bad grounding or isn't grounded, LPE and NPE icons on lower left part of LCD will flash simultaneously. Ensure the neutral terminal of the socket is firmly connected. If the neutral terminal is badly or not connected, LN and NPE icons on lower left part of LCD will flash simultaneously. Ensure live and neutral terminals of the power socket are not reversely connected when measuring line impedance/prospective short current, otherwise LPE, LN and NPE icons on the lower left part of LCD will flash simultaneously. Please take extreme caution when making the measurement for it is performed under high-voltage status.

XIV. Taking Auto RCD Tests (See Figure 7)

Figure 7 Description: Connect the test leads to a power socket. The instrument performs a sequence of RCD tests automatically.

To Test RCD Automatically:

1. Turn the rotary switch to AUTO position.
2. Insert three connectors of one-plug test leads or three separate test leads into the three input terminals of the Tester (red to red, green to green, black to black). Refer to Figure 7.
3. Plug the plug into domestic 220V socket.
4. Press TEST button to start.

Tips: Auto RCD Test is designed to measure trip times in one time just by pressing one button down. The Tester will complete all RCD measurements before proceeding into next test. All these test data will be saved in the Tester; pressing F3 can review all the data. RCD measurements are taken in following order:

• UT593: 1. 1/2*IΔn/0, 2. 1/2*IΔn/180, 3. 1*IΔn/0, 4. 1*IΔn/180, 5. 5*IΔn/0, 6. 5*IΔn/180
• UT595: 1. 1/2*IΔn/0, 2. 1/2*IΔn/180, 3. 1*IΔn/0, 4. 1*IΔn/180, 5. 2*IΔn/0, 6. 2*IΔn/180, 7. 5*IΔn/0, 8. 5*IΔn/180

Understanding F1-F4 Buttons:

• F1: Long press for 2 seconds to turn on/off the backlight.
• F2: Press to toggle between RCD types (AC and DC, full and half wave) and Timer mode. Timer: under this mode, press down TEST button and the Tester will count down from 30s to 0s before enabling RCD test.
• F3: Press to recall all saved data from the whole test.
• F4: Press to select RCD test current.

[Caution] Please make sure domestic 220V in the power socket is normally supplied. If the socket is unable to be powered normally or de-energized, LPE and LN icons on lower left part of LCD will flash simultaneously. Ensure the socket is properly grounded. If the socket has bad grounding or isn't grounded, LPE and NPE icons on lower left part of LCD will flash simultaneously. Ensure the neutral terminal of the socket is firmly connected. If the neutral terminal is badly or not connected, LN and NPE icons on lower left part of LCD will flash simultaneously. Ensure live and neutral terminals of the power socket are not reversed when testing RCD, otherwise LPE, LN and NPE icons on the lower left part of LCD will flash simultaneously. Please take extreme caution when taking auto RCD tests for it is performed under high-voltage status.

XV. Taking Regular RCD Tests (See Figure 7)

Figure 7 Description: Connect the test leads to a power socket. Select specific RCD test parameters (current, phase angle) and press TEST.

To take regular RCD test:

1. Turn the rotary switch to IΔn, 1*IΔn, 2*IΔn (for UT595 only), or 5*IΔn position.
2. Insert three connectors of one-plug test leads or three separate test leads into the three input terminals of the Tester (red to red, green to green, black to black). Refer to Figure 7.
3. Plug the plug into domestic 220V socket.
4. Press TEST button to start.

Understanding F1-F4 Buttons:

• F1: Long press for 2 seconds to turn on/off the backlight; short press to toggle between 0° / 180°.
• F2: Press to toggle between RCD types (AC and DC, full and half wave) and Timer mode. Timer: under this mode, press down TEST button and the Tester will count down from 30s to 0s before enabling RCD test.
• F3: Invalid.
• F4: Press to select RCD rated test current, refer to rated options in following order: 10mA, 30mA, 100mA, 300mA, 500mA.

Tips: The leakage current will be different depending on the selected current multiplier. Refer to the following table for detailed relationship.

[Caution] Please make sure domestic 220V in the power socket is normally supplied. If the socket is unable to be powered normally or de-energized, LPE and LN icons on lower left part of LCD will flash simultaneously. Ensure the socket is properly grounded. If the socket has bad grounding or isn't grounded, LPE and NPE icons on lower left part of LCD will flash simultaneously. Ensure the neutral terminal of the socket is firmly connected. If the neutral terminal is badly or not connected, LN and NPE icons on lower left part of LCD will flash simultaneously. Ensure live and neutral terminals of the power socket are not reversed when testing RCD, otherwise LPE, LN and NPE icons on the lower left part of LCD will flash simultaneously. Please take extreme caution when taking regular RCD tests for it is performed under high-voltage status.

XVI. Measuring RCD Trip Current (See Figure 7)

Figure 7 Description: Connect the test leads to a power socket. The instrument gradually increases current to determine the trip point.

To measure trip current:

1. Turn the rotary switch to RAMP position.
2. Insert three connectors of one-plug test leads or three separate test leads into the three input terminals of the Tester (red to red, green to green, black to black). Refer to Figure 7.
3. Plug the plug into domestic 220V socket.
4. Press TEST button to start.

Understanding F1-F4 Buttons:

• F1: Long press for 2 seconds to turn on/off the backlight; short press to toggle between 0° / 180°.
• F2: Press to toggle between RCD types (AC and DC, full and half wave) and Timer mode. Timer: under this mode, press down TEST button and the Tester will count down from 30s to 0s before enabling RCD test.
• F3: Invalid.
• F4: Press to select RCD rated leakage test current, refer to rated options in following order: 10mA, 30mA, 100mA, 300mA, 500mA.

Tips: The leakage current will be different depending on the selected waveform. Refer to the following table for detailed relationship.

[Caution] Please make sure domestic 220V in the power socket is normally supplied. If the socket is unable to be powered normally or de-energized, LPE and LN icons on lower left part of LCD will flash simultaneously. Ensure the socket is properly grounded. If the socket has bad grounding or isn't grounded, LPE and NPE icons on lower left part of LCD will flash simultaneously. Ensure the neutral terminal of the socket is firmly connected. If the neutral terminal is badly or not connected, LN and NPE icons on lower left part of LCD will flash simultaneously. Ensure live and neutral terminals of the power socket are not reversed when testing RCD trip current, otherwise LPE, LN and NPE icons on the lower left part of LCD will flash simultaneously. Please take extreme caution when testing RCD trip current for it is performed under high-voltage status.

XVII. Replacing the Battery

[Danger] To avoid electric shock, remove all test leads from the Tester before replacing the battery. Do not measure with the battery cover opened.

[Danger] Do not mix old and new batteries or different types of batteries.

When the low battery indicator [Low Battery Symbol] shows on LCD, please replace the battery promptly.

To replace the battery, follow steps as below:

1. Power off the Tester, set the rotary switch to OFF, and remove away the test leads.
2. Unscrew the battery cover, remove the battery cover and replace the batteries with 8pcs new batteries.
3. Screw back the battery cover and tighten the screws.

XVIII. Maintenance & Repair

Cleaning the Casing: Clean the Tester's surface with a soft cloth or sponge dampened with water. To avoid damage to the Tester, do not submerge it into water. Dry the Tester before storing it if it is wet.

Repair: When it becomes necessary to calibrate or repair the Tester, please have it serviced by qualified professional personnel or a designated service center.