HT Italia PV-ISOTEST 1500VDC Photovoltaic System Insulation Tester

Key Features At A Glance

• Tests photovoltaic systems up to 1500VDC — CAT III 1500VDC / CAT III 1000VAC measurement category
• DUAL mode insulation test simultaneously measures positive and negative pole resistance without external short-circuit switch
• GFL (Ground Fault Locator) function identifies single low-insulation faults within ±1 module accuracy on a string
• Insulation test voltages of 250V, 500V, 1000V, and 1500V selectable for PV active conductor verification
• TIMER mode insulation testing with automatic DAR (Dielectric Absorption Ratio) and PI (Polarization Index) calculation
• Protective conductor continuity (RPE) test with >200mA DC test current and immediate OK/NO result
• DC and AC TRMS voltage measurement up to 1500VDC and 1000VAC between poles and earth
• Designed per IEC/EN62446-1 for PV system commissioning, verification, and maintenance

The HT Instruments PV-ISOTEST is a handheld photovoltaic insulation tester engineered specifically for verification, maintenance, and safety testing of PV systems operating up to 1500VDC. As modern PV installations increasingly adopt 1500V rated architectures to enable longer strings, higher generated power, and reduced balance-of-system losses, the verification instruments serving those installations must extend beyond the legacy 1000V envelope. The PV-ISOTEST is positioned by HT Instruments as a purpose-built solution for that 1500V-class PV verification requirement, with the test voltages, measurement categories, and standardized test procedures aligned to IEC/EN62446-1.

The PV-ISOTEST is used by PV commissioning technicians, O&M field personnel, and inspection engineers performing the safety checks specified in IEC/EN62446-1: insulation resistance of active PV conductors, continuity of protective conductors, and DC/AC voltage measurement between poles and earth. The DUAL insulation mode is intended for end-to-end verification of an unearthed PV field, providing a single-test OK/NO result for the positive and negative conductors simultaneously without requiring an external switch to short the array. The GFL function is intended for locating a single low-insulation fault along a string — for example, a fault caused by water or humidity ingress — with the instrument reporting the approximate module position of the fault.

Brand Heritage

HT Instruments (HT Italia S.r.l.) is an Italian manufacturer of electrical and photovoltaic test and measurement instrumentation, founded in 1983 and headquartered in Faenza, Italy. The company operates under continuous ownership and has not been part of an acquisition or rebrand within the T&M sector.

Accessories Supplied

• KITGSC4 Set of 4 banana cables 4mm + 4 alligator clips
• KITPCMC4 Set of 2 MC4 banana adapters
• VA507 Hard carrying case
• SP-5100 Carrying straps
• TOPVIEW2006 PC Windows software + optical/USB connection cable (order code: C2006)
• YAMUM0077HT0 User manual on CD-ROM
• YAMUM0076HT0 Quick reference guide
• ISO calibration report

Product Core & Specifications

DC Voltage
Range (V)	Resolution (V)
3 to 1500	1
Accuracy: ±(1.0% reading + 2 digits)

AC TRMS Voltage
Range (V)	Resolution (V)
3 to 1000	1
Accuracy: ±(1.0% reading + 3 digits)

Insulation Resistance (MΩ) – DUAL Mode
Test Voltage DC [V]	Range [MΩ]	Resolution [MΩ]	Accuracy
250, 500, 1000, 1500	0.1 to 0.99	0.01	±(5% reading + 5 digits)
1.0 to 19.9	0.1
20 to 100	1

Insulation Resistance (MΩ) – TIMER Mode
Test Voltage DC [V]	Range [MΩ]	Resolution [MΩ]	Accuracy
250, 500, 1000, 1500	0.1 to 9.99	0.01	±(5.0% reading + 5 digits)
10.0 to 99.9	0.1

Continuity of Protective Conductors (RPE)
Range (Ω)	Resolution (Ω)	Accuracy
0.00 to 9.99	0.01	±(2% reading + 2 digits)
10.0 to 99.9	0.1
100 to 1999	1
Test current: >200 mA DC up to 5Ω (cables included); Resolution: 1 mA; Accuracy: ±(5.0% reading + 5 digits); Open-circuit voltage: 4 < Vo < 10V

GFL (Ground Fault Locator) Function
Test Voltage DC [V]	Range [MΩ]	Resolution [MΩ]	Accuracy	Accuracy of Position
250, 500, 1000, 1500	0.1 to 0.99	0.01	±(5.0% rdg + 5 dgt)	± 1 module
1.0 to 19.9	0.1
20 to 100	1

Power Supply
Battery type	6 x 1.5V alkaline batteries type AA LR06 or 6 x 1.2V rechargeable batteries type AA LR06
Battery duration	approx. 500 tests (for each function)
Auto Power OFF	after 5 minutes' idling

Output Interface
PC interface	optical/USB

Reference Standards
Instrument safety	IEC/EN61010-1, IEC/EN61010-2-030, IEC/EN61010-2-033, IEC/EN61010-2-034
EMC	IEC/EN61326-1
Accessory safety	IEC/EN61010-031
General	IEC/EN62446
MΩ measurement	IEC/EN61557-2
RPE measurement	IEC/EN61557-4
Insulation	double insulation
Pollution level	2
Measurement category	CAT III 1500VDC, CAT III 1000VAC; MAX 1500VDC / 1000VAC between inputs

Important: GFL fault-location accuracy of ±1 module is specified only when the test is performed with Vtest ≥ Vnom on a single string disconnected from the inverter, overvoltage protection, and earth connections; performed upstream of any blocking diodes; with a single fault present at insulation resistance below 0.1MΩ; and under environmental conditions similar to those in which the fault occurred.Important: The GFL function provides correct results with the following conditions: test carried out with Vtest ≥ Vnom on a single string disconnected from the inverter, from possible overvoltage protections and earth connections; test carried out upstream of possible blocking diodes; single fault of low insulation located at any position in the string; insulation resistance of the single fault < 0.1 MΩ; environmental conditions similar to those in which the fault occurred.Important: Measurement category: CAT III 1500VDC, CAT III 1000VAC. Maximum 1500VDC / 1000VAC between inputs.Recommended pairing: use the included KITPCMC4 MC4 banana adapters to connect the PV-ISOTEST directly to standard MC4 PV string terminations during DUAL-mode and GFL testing.

Please review the Manufacturer's Data Sheet to verify published specifications. Feedback on this webpage is always welcome — please reach out to your Test Architect at any time for questions or concerns. Thank you, we truly appreciate you being our customer.