Rated CAT IV 600 V, the UT513B applies selectable test voltages from 250 V to 5 kV and reads insulation resistance up to 2 TΩ — the headroom you need for medium-voltage motors, transformers, switchgear, and long cable runs. It runs the timed diagnostics that tell you whether insulation is actually healthy or just passing a spot check: Polarization Index, Dielectric Absorption Ratio, and a 10%-of-range stepped-voltage profile that surfaces weaknesses a single fixed-voltage reading misses.
Leakage current shows live during the test, the circuit auto-discharges when you're done, and a high-voltage alarm flags an energized lead. The instrument stores 999 result sets and exports over USB for compliance records, and a 14.8 V 5200 mAh rechargeable pack carries a full day of field testing. It's backed by UNI-T's nearly 40 years of test-meter manufacturing.
Key Features
Five selectable test voltages: 250 V, 500 V, 1000 V, 2500 V, 5000 V
Insulation resistance up to 2 TΩ, accuracy ±(5%+5)
PI (Polarization Index) and DAR timed diagnostics with 0 s–99 m 59 s timer
10%-of-range stepped-voltage profiling for insulation stress testing
Live leakage-current display and automatic discharge after test
High-voltage output alarm
Comparison function for pass/fail against a set threshold
999-set storage with USB transfer to PC
CAT IV 600 V; 14.8 V 5200 mAh rechargeable Li-ion
UT513B Details
Multi-Voltage Insulation Testing
Five fixed test voltages from 250 V to 5 kV let you match the test to the asset — low voltages for control and electronics wiring, 2.5 kV and 5 kV for motor windings, transformers, and medium-voltage cable. Resistance reads up to 2 TΩ, so modern high-resistance insulation stays on-scale.
PI & DAR Diagnostics
The UT513B times the resistance curve to calculate Polarization Index and Dielectric Absorption Ratio. Both separate genuinely dry, sound insulation from windings that read acceptable cold but are holding moisture or contamination — the difference between a motor you return to service and one you flag.
Stepped-Voltage Profiling
Beyond a fixed-voltage reading, the UT513B steps the test voltage in 10% increments across the selected range. Watching how resistance responds as stress rises exposes marginal insulation that a single endpoint reading reports as a pass.
Auto-Discharge & High-Voltage Alarm
Capacitive test objects store charge. The UT513B discharges the circuit automatically when a test ends, and a high-voltage alarm warns whenever a lead is live — the safety basics you want on a 5 kV instrument.
Data Logging & Transfer
Store up to 999 result sets on the instrument and move them to a PC over USB for reports and asset records. The comparison function sets a pass/fail threshold so repeat tests stay consistent across equipment and across technicians.
Field Build
A 14.8 V 5200 mAh rechargeable lithium pack runs a full testing day, and the CAT IV 600 V rating covers work on industrial distribution and outdoor utility equipment.
Compare the UT513 Series
UT512E
UT513A
UT513B
UT513C
Max test voltage
2500 V
5 kV
5 kV
5 kV
Max insulation resistance
2.5 TΩ
1 TΩ
2 TΩ
5 TΩ
Voltage stepping (10% of range)
Yes
—
Yes
Yes
PI / DAR diagnostics
PI
PI
PI / DAR
PI / DAR
Capacitance measurement
2 µF
—
—
0.01–15 µF
Data storage
999 sets
18 sets
999 sets
999 sets
Bluetooth app
—
—
—
Yes
Safety rating
CAT IV 600 V
CAT III 600 V
CAT IV 600 V
CAT IV 600 V
Applications
Rotating-machinery winding insulation on motors and generators; transformer and switchgear maintenance; cable and feeder testing on medium-voltage runs; and panel and equipment commissioning where insulation has to be verified before energizing.
Frequently Asked Questions
What test voltages does the UT513B provide?
Five selectable steps: 250 V, 500 V, 1000 V, 2500 V, and 5000 V.
What do PI and DAR tell me?
Both are timed ratios that reveal moisture and contamination in insulation that a single resistance reading can miss.
How is the UT513B different from the UT513A and UT513C?
The UT513A is the basic 1 TΩ / CAT III model; the UT513B reads to 2 TΩ with stepped-voltage profiling at CAT IV; the UT513C extends to 5 TΩ and adds capacitance measurement and a Bluetooth app.
⚠️ 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.
