Fluke 1535 Insulation Tester - Fluke-1535

The Fluke 1535 Insulation Resistance Tester bridges the gap between basic 500V/1000V insulation testers and high-voltage equipment like the 1550C, providing selectable test voltages from 500V to 2500V DC for testing larger motors, longer cable runs, and medium-voltage equipment that requires higher test stress for meaningful insulation assessment. With PI and DAR testing capability, the 1535 covers the mid-range of insulation testing applications in industrial maintenance programs: large industrial motors (100 horsepower and above), medium-voltage power cables, large transformers, and switchgear assemblies where 500V or 1000V test voltage is insufficient for the equipment's insulation system rating.

Key Features

• 500V to 2500V Selectable Test Voltages: IEEE Standard 43-2013 recommends test voltages related to equipment voltage rating, motors rated at 1kV to 2.5kV are typically tested at 2000V to 2500V. The 1535's test voltage range covers the lower end of medium-voltage equipment testing that a standard 500V or 1000V tester cannot address with appropriate test stress.
• Insulation Resistance to 20GΩ: The extended resistance range (vs 2,000MΩ on the 1507) measures the very high insulation resistance values typical of large, new, or recently dried motors and medium-voltage cables that read at the top of lower-range testers.
• PI and DAR Testing: Automatically calculates and displays Polarization Index (10-min/1-min ratio) and Dielectric Absorption Ratio (60-sec/30-sec ratio) for insulation condition assessment beyond simple resistance readings.
• Automated Testing Sequence: Programmed test sequences reduce operator involvement during the 10-minute PI test interval, reducing the risk of test interruption and ensuring consistent test conditions.
• Auto-Discharge: Automatically discharges capacitive test objects (motors, cables) after each test for technician safety and accurate sequential measurements.

Technical Specifications Overview

The 1535 tests at 500V, 1000V, 2000V, and 2500V DC, measuring insulation resistance from 0.1MΩ to 20GΩ with ±5% accuracy. It includes PI and DAR testing and auto-discharge. The 1535 is positioned between the 1507 (single 500V test voltage, 2,000MΩ range) and the 1550C (5kV test voltage for switchgear and large power equipment).

Medium-Voltage Equipment Applications

• Large industrial motor (100HP+) winding insulation testing at 2000V or 2500V per IEEE 43
• Medium-voltage power cable insulation testing (1kV to 2.5kV rated cables)
• Industrial transformer winding insulation assessment
• Switchgear insulation verification at test voltages above 1000V

Fluke 1535 Calibration

PJi operates an ISO/IEC 17025 Accredited Calibration Lab and provides NIST-traceable calibration for the Fluke 1535 at the time of purchase, add calibration to your order at checkout. Our calibration documentation satisfies FAA Part 145 tool control requirements, ISO 9001 quality system records, and AS9100 traceability requirements. PJi is the one-stop source: the instrument and the calibration certificate in a single transaction. Calibration-only companies (Custom-Cal, Fox Valley Metrology, ATS) cannot sell you the instrument. Amazon and Grainger cannot calibrate it. PJi does both.

Why Buy from Pilot John International

Pilot John International is an authorized Fluke distributor with specialized expertise serving aviation maintenance, FAA Part 145 repair stations, and industrial MRO facilities. Unlike Amazon, Grainger, or Test Equipment Depot, which sell Fluke instruments but offer zero calibration services, PJi's in-house ISO/IEC 17025 Accredited Calibration Lab calibrates your instrument at purchase. We stock the full Fluke catalog, ship same-business-day on in-stock items, and our technical staff understands the demands of aviation and industrial electrical maintenance.