The UT505B is the wider-range model in the UT505 pair: a CAT IV 600 V insulation tester and True-RMS digital multimeter in one handheld, reading insulation resistance up to 200 GΩ at test voltages from 50 V to 1000 V to IEC 61557. It adds an automatic fuse check to the combination, so the meter verifies its own current-input fuse before you rely on a reading.
Insulation testing includes Polarization Index and DAR diagnostics, stepped-voltage testing, and automatic discharge; the 6000-count multimeter covers AC/DC voltage, resistance, capacitance, and frequency, with 99 result groups stored on-board. It's backed by UNI-T's nearly 40 years of test-meter manufacturing.
Key Features
Insulation resistance up to 200 GΩ, accuracy ±(1.5%+5)
Test voltages: 50 V, 100 V, 250 V, 500 V, 1000 V (IEC 61557)
True-RMS 6000-count digital multimeter built in
Automatic fuse check
AC/DC voltage to 600 V; capacitance, frequency, low and general resistance
PI and DAR insulation diagnostics
Stepped-voltage testing and automatic discharge
99-group data storage; CAT IV 600 V
UT505B Details
Two Instruments in One
Like the UT505A, the UT505B pairs a 1000 V insulation tester with a full True-RMS multimeter, so one handheld covers insulation testing and the voltage, resistance, capacitance, and frequency measurements that go with it.
Insulation Testing to 200 GΩ
A 200 GΩ measurement range — ten times the UT505A — keeps high-resistance insulation on-scale, with five test voltages from 50 V to 1000 V and IEC 61557 compliance for motor, cable, and switchgear work.
Automatic Fuse Check
The UT505B verifies its own current-input fuse automatically, so a blown fuse can't quietly turn a current measurement into a misleading reading — a useful safeguard in daily field use.
PI, DAR & Stepped Voltage
Timed PI and DAR diagnostics and stepped-voltage testing reveal moisture, contamination, and marginal insulation that a single fixed-voltage reading would pass.
Safety & Field Build
Automatic discharge clears stored charge after each test, the CAT IV 600 V rating suits distribution work, and 99 result groups store on-board for later review.
Compare the UT505 Series
UT505A
UT505B
Max insulation resistance
20 GΩ
200 GΩ
Auto fuse check
—
Yes
Applications
Combined insulation and electrical testing on motor windings, cables, and switchgear where a wider 200 GΩ range is needed; preventive maintenance with one tool for both jobs; and field troubleshooting that moves between insulation testing and routine multimeter measurements.
Frequently Asked Questions
How high does the UT505B measure insulation resistance?
Up to 200 GΩ — ten times the range of the UT505A.
What is the automatic fuse check?
The meter verifies its own current-input fuse automatically, so a blown fuse won't produce a misleading current reading.
Is the UT505B also a multimeter?
Yes — a True-RMS 6000-count multimeter with AC/DC voltage, resistance, capacitance, and frequency, in addition to insulation testing.
⚠️ WARNING (California Proposition 65): This product may contain chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information, please visit www.P65Warnings.ca.gov.
