The UT503PV is built for solar work: it measures insulation resistance on live photovoltaic systems at up to DC 1000 V, so a string can be tested without taking the array offline or short-circuiting panels — including after dark. It tests to IEC 62446 with test voltages from 125 V to 1000 V and a measurement range up to 4000 MΩ, and it's rated CAT II 1000 V / CAT III 600 V with an IP54 sealed body for outdoor use.
Stepped-voltage testing, a comparison function, automatic discharge, and a high-voltage alarm cover the safety and diagnostic basics, while 1000 result sets store on-board and transfer over USB or a Bluetooth app for commissioning reports. It's backed by UNI-T's nearly 40 years of test-meter manufacturing.
Key Features
Live PV insulation testing up to DC 1000 V — no array shutdown required
Test voltages: 125 V, 250 V, 500 V, 1000 V (IEC 62446)
Insulation resistance up to 4000 MΩ, accuracy ±(1.5%+5)
Stepped-voltage testing and comparison function
Automatic discharge and high-voltage alarm
1000-set storage; USB and Bluetooth app
CAT II 1000 V / CAT III 600 V; IP54 sealed body
Compact ~0.5 kg handheld for rooftop and field work
UT503PV Details
Live PV Insulation Testing
The UT503PV measures insulation resistance on energized photovoltaic strings up to DC 1000 V, so you can verify a system without disconnecting it or short-circuiting panels — and because it doesn't depend on irradiance, testing works after dark when the array is at a stable voltage.
Built to IEC 62446
Test voltages from 125 V to 1000 V and a 4000 MΩ range follow the IEC 62446 framework for commissioning and periodic verification of PV installations, giving a documented insulation result for sign-off.
Safety for High-Voltage DC
Automatic discharge clears stored charge after each test, a high-voltage alarm warns of live leads, and the CAT II 1000 V / CAT III 600 V rating with an IP54 sealed body suits outdoor rooftop and ground-mount work in the field.
Documentation & Connectivity
Store up to 1000 result sets and transfer them by USB or a Bluetooth app, with a comparison function for pass/fail thresholds — practical for commissioning packs and recurring maintenance records.
Applications
Solar PV installation and commissioning to IEC 62446; periodic insulation checks on operating arrays; EV-charging and battery-energy-storage DC wiring verification; and rooftop and ground-mount maintenance where live testing avoids taking a system offline.
Frequently Asked Questions
Can the UT503PV test energized PV systems?
Yes — it measures insulation resistance on live PV strings up to DC 1000 V, so the array does not have to be shut down or short-circuited.
Can it test at night?
Yes. Because the measurement does not rely on irradiance, testing works after dark when the string is at a stable voltage.
What standard does it follow?
Test voltages and ranges follow IEC 62446 for photovoltaic system commissioning and verification.
⚠️ 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.
