Victor 3123/3125/3126 Series Professional Digital Insulation Resistance Tester | 250V–5000V Selectable Output, Up to 2.5TΩ Measurement, Built-in Leakage Current & Voltage Test

Wide Voltage Selection for Every Application

• The 3123 model offers 250V, 500V, 1000V, and 2500V output – this insulation resistance tester covers low-voltage and medium-voltage installations.
• The 3125 model adds 5000V capability – this insulation resistance tester is perfect for high-voltage cable and transformer testing.
• The 3126 model delivers the full range from 250V to 5000V with extended resistance measurement up to 2.5TΩ – the ultimate insulation resistance tester for the most demanding applications.
• Each insulation resistance tester provides stable open-circuit voltage with tolerances of +20%/-0% (250V/500V) and +10%/-0% (1000V/2500V/5000V), ensuring consistent, repeatable results.

Exceptional Insulation Resistance Measurement Range

• The 3123 insulation resistance tester measures up to 250GΩ at 2500V – ideal for motor and generator insulation testing.
• The 3125 insulation resistance tester extends to 500GΩ at 5000V – suitable for medium-voltage cable systems.
• The 3126 insulation resistance tester reaches an incredible 2.5TΩ (2500GΩ) at 5000V – the go-to insulation resistance tester for high-voltage transmission lines and large power transformers.
• All models offer 0.0~99.9MΩ, 100~999MΩ, and 1.00~9.99GΩ ranges across all voltages, with progressive ranges extending into GΩ and TΩ for higher-end models.

Built-in Leakage Current Testing for Comprehensive Diagnostics

• Unlike basic insulation testers, this insulation resistance tester series includes precision leakage current measurement from 0.5nA to 5000μA.
• Ultra-low current detection (0.5nA range) makes this insulation resistance tester sensitive enough for capacitor leakage and semiconductor junction testing.
• Multiple ranges (5nA, 50nA, 500nA, 5μA, 50μA, 250μA, 500μA, 3000μA, 5000μA) allow this insulation resistance tester to adapt to a wide variety of components and systems.
• Leakage current data provides additional insight into insulation condition, making this insulation resistance tester a more complete diagnostic tool.

Integrated AC/DC Voltage Measurement & Safety Features

• Each insulation resistance tester measures DC voltage from 0 to ±1000V and AC voltage from 30 to 750V (50/60Hz) with 1V resolution and ±2%+3 accuracy – no need to carry a separate voltmeter.
• Automatic discharge function safely discharges capacitive loads after testing – this insulation resistance tester protects both the user and the equipment under test.
• Over-range prompt alerts the operator when measurements exceed the selected range, preventing misinterpretation of results.
• Input protection safeguards the insulation resistance tester from accidental high-voltage surges.

User-Centric Design for Efficiency and Safety

• 9999-count large display with bright white backlight – this insulation resistance tester provides excellent readability even in dimly lit electrical rooms.
• Same-screen dual display allows this insulation resistance tester to show voltage and resistance, or leakage current and voltage simultaneously – reducing test time and improving efficiency.
• Data storage function captures and saves measurement results for later review – this insulation resistance tester eliminates manual note-taking.
• USB data transfer enables easy report generation and data analysis – this insulation resistance tester integrates seamlessly into modern digital workflows.
• Automatic shut-down conserves battery life, ensuring your insulation resistance tester is ready when you need it.

Three Models to Match Your Requirements and Budget

• 3123 – Essential insulation resistance tester with 250V–2500V output and up to 250GΩ resistance measurement, plus full leakage and voltage functions.
• 3125 – Advanced insulation resistance tester with 250V–5000V output and up to 500GΩ resistance measurement – ideal for more demanding industrial applications.
• 3126 – Premium insulation resistance tester with 250V–5000V output and up to 2.5TΩ resistance measurement – the ultimate tool for high-voltage specialists and utility maintenance crews.

Built to Last – Rugged and Reliable

• Engineered for daily use in harsh industrial environments – this insulation resistance tester withstands dust, moisture, and temperature variations.
• Quality construction ensures long service life, making this insulation resistance tester a sound investment for any electrical maintenance department.
• Clear, intuitive controls allow operators of all skill levels to use this insulation resistance tester confidently and safely.

Ideal Applications for the 3123 Series Insulation Resistance Tester

• Electrical installation commissioning and acceptance testing
• Preventive maintenance of motors, generators, and transformers
• Cable insulation integrity verification (LV, MV, and HV)
• Switchgear and busbar insulation testing
• Capacitor leakage and semiconductor junction testing
• Safety inspections in utilities, manufacturing, and commercial buildings
• Training and educational programs in electrical engineering

Safety & Compliance

• Every insulation resistance tester in this series is designed with operator safety as the top priority.
• Automatic discharge and input protection features ensure this insulation resistance tester meets the highest safety standards.
• Clear visual and audible indicators warn of live circuits, making this insulation resistance tester a safe choice for all users.