PosiTest® HHD

High voltage Holiday Detector

Detects holidays, pinholes and other discontinuities using pulse DC
  • Lightweight, ergonomic design provides comfortable all-day use, reducing operator fatigue
  • Regulated pulse DC voltage output that won't change under load— ±5% voltage accuracy
  • Voltage calculator feature—choose one of 11 international standards, and input the coating thickness to automatically calculate the required test voltage
  • Extensive electrode options—choose from a wide range of rolling spring and flat wire brush electrodes or use electrodes from other manufacturers with optional adaptors—custom sizes available upon request
  • Long Form Certificate of Calibration included with each instrument

Conforms to ASTM D4787/D5162/G62, ISO 29601, NACE SP0188/SP0274/SP0490, AS3894.1



  • Easy-to-use with bright, multicolor LCD
  • Ready to measure—comes with everything needed for testing
  • Audibly and visibly alerts when flaws/holidays are detected
  • Lightweight, ergonomic design provides comfortable all-day use, reducing fatigue
  • Voltage calculator feature—choose one of 11 international standards, and input the coating thickness to automatically calculate the required test voltage


  • A wide range of rolling spring electrodes and wire brushes are available. Custom sizes available upon request.
  • Optional handheld wand accessory coverts the detector into a wand configuration ideal for testing hard-to-reach areas (suitable for voltages
    < 15 kV)
  • Industry-standard connectors and adaptors for compatibility with nearly all existing electrodes
  • User adjustable voltage range from
    0.5 – 35 kV



  • Strobe light and loud audible alarms emitted when a holiday is detected. Audio alarm mode can be adjusted for differing environments.
  • Removable Smart lithium-ion battery provides power for up to 40 hours of continuous measurement


  • Press and hold Safety Trigger helps prevent accidental high voltage generation
  • 7.6 m (25') ground (earth) cable with locking connector and spring clamp
  • Shock proof/creep proof—internally sealed to minimize creep distance to high voltage components. Designed in accordance with IEC 61010-1.


  • Built-in certified voltmeter (crest meter, jeep meter) displays and regulates the voltage at the electrode
  • Long Form Certificate of Calibration included with each instrument
  • Conforms to national and international standards including ISO, ASTM and NACE


Output Voltage Range

0.5 — 35 kV

Output Voltage Adjustment

0.5 kV — 1 kV: 10 Volt Steps

1 kV — 35 kV: 100 Volt Steps

Output Accuracy


Pulse Duration

10 μs

Pulse Repetition Rate

30 Hz

up to 20 mm (780 mils)*

Coating Thickness Range
Typical Battery Life

Based on selected voltage and load

Ø 12" Rolling Spring @ 10kV, 40 hrs.

Ø 40" Rolling Spring @ 10kV, 30 hrs.

Operating Temperature

-20° to 60°C (-4° to 140°F)

* Based on NACE SP0274-2011 recommendations


PosiTest HHD Kit
PosiTest HHD Kit
PosiTest HHD,
7.6 m (25') ground (earth) cable with ground clip,
Li-ion battery pack with built-in charge state indicator,
Smart charger with universal AC voltage input,
Stainless steel fan brush,
50 cm (20" ) electrode rod with thumb screw,
Shoulder strap,
Instruction Manual,
Durable Pelican Storm case,
Long Form Certificate of Calibration traceable to NIST,
Two year warranty
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Rolling spring electrodes for PosiTest HHD
Rolling Spring Electrodes
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Flat Wire Brush Electrodes for PosiTest HHD
Flat Wire Brush Electrodes
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Video Thumbnail
PosiTest HHD High voltage Holiday Detector - Testing Coatings for Pinholes and Voids



What is a holiday detector?

A holiday detector is a non-destructive instrument for detecting discontinuities in a coating system including holidays, pinholes, and cracks. Other names include porosity detector, continuity tester, and holiday tester.

There are two types of pinhole detectors: low voltage (wet sponge) and high voltage (spark tester). Low voltage detectors, like the PosiTest LPD, are typically used on coating systems less than 500 µm (20 mils) thick. High voltage spark testers, like the PosiTest HHD operate at voltages up to 35,000V and are typically used on coatings more than 500 µm (20 mils) thick.


What is meant by the term 'stick type' or 'wand' holiday detector?

A 'stick type' holiday detector is a standalone detector with internal battery power and electrodes that attach to the end of an extension rod (stick). 'Wand' or 'Belt-style' detectors typically have a separate battery pack carried on the belt or shoulder strap and electrodes that attach to a handheld wand. The PosiTest HHD is the first combination stick type/wand type instrument on the market. With the optional handheld wand accessory, the PosiTest HHD converts into a wand style instrument suitable for voltages less than 15k.


How is a high-voltage test performed?

A high-voltage holiday test is performed by moving a charged electrode over the coated surface. When a holiday is encountered, current flows from the electrode into the substrate. The current returns to the detector through the ground (earth) wire, completing the circuit and triggering audible and visible alarms. An integrated peak reading voltmeter measures and displays the output voltages on the display while in use.


Why is porosity measurement important?

After a protective coatings has been applied, it is important to ensure there are no defects or discontinuities present that expose the substrate beneath. Small areas of thin or missing coating, called 'pinholes' or 'holidays', can become foci for corrosion and drastically reduce the life of a protective coating system. They can be invisible to the naked eye. Porosity detectors are often used in applications where corrosion is difficult to monitor, or in aggressive service environments where performance of the protective coating is critical.


How does the PosiTest HHD measure coatings on concrete?

When measuring coating thickness, concrete is not considered a 'conductive' substrate, as it is much less conductive than metal. However, concrete is still slightly conductive, and can carry enough current to allow holiday detectors to function. Therefore, for the purposes of holiday detection, concrete is considered a 'conductive' substrate.


Are custom size electrodes available?

Yes. DeFelsko manufactures a wide variety of rolling spring and flat wire brush electrodes. Custom sizes are available upon request.


Are internal pipe, half-circle, and other types of electrodes available?

At launch, flat brush and spring electrodes will be available in pre-stocked and custom lengths, in addition to the handheld rubber paddle and fan brush. DeFelsko plans to add additional types of electrodes in the future, based on demand. If you have a request for an electrode configuration not currently offered by DeFelsko, please let us know.


What electrodes are compatible with the PosiTest HHD?

The PosiTest HHD offers industry-standard connectors and adaptors for compatibility with nearly all existing electrodes including SPY, PCWI and Tinker & Rasor.


What is the PosiTest HHD Verifier?

The PosiTest HHD Verifier is a calibrated voltmeter (crest meter, jeep meter) ideal for verifying the operating voltage of both Pulse and Continuous DC holiday detectors in the range from 500 to 35,000 Volts.


Is the PosiTest HHD Verifier necessary to use the PosiTest HHD High voltage Holiday Detector?

No. The PosiTest HHD features a built-in voltmeter (crest meter, jeep meter) with a traceable Long Form Certificate of Calibration. However, some standards call for a standalone voltmeter.


How is the PosiTest HHD calibrated at DeFelsko?

Each PosiTest HHD is calibrated using instruments traceable to a National Metrology Lab. A Long Form Certificate of Calibration containing actual measure values is included with every instrument.


Are there any special shipping considerations for the PosiTest HHD's Lithium-Ion batteries?

The PosiTest HHD and one additional spare battery (charged less than 30% of capacity) can be shipped via surface and air transport on the major carriers (UPS, FedEx, and DHL) to all countries, subject to additional labelling requirements.

Note: When returning the PosiTest HHD for service or repair, DO NOT include any batteries.


Replacement Fan Brush ElectrodeReplacement Fan Brush Electrode

Stainless steel — 5 cm (2”)

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Flat Wire Brush ElectrodesFlat Wire Brush Electrodes

Stainless steel — assorted sizes available: 5 to 120 cm (2 – 48”)

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Handheld WandHandheld Wand

Converts the PosiTest HHD to a wand-type instrument

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Electrode RodsElectrode Rods

Choose between 13 cm (5") and 50 cm (20") rods

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Spring ConnectorSpring Connector

Connect the PosiTest HHD to DeFelsko or SPY rolling spring electrodes

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Conductive Rubber PaddleConductive Rubber Paddle

102mm/4" Conductive Rubber Paddle for PosiTest HHD

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PosiTest HHD VerifierPosiTest HHD Verifier

Standalone voltmeter (crest meter, jeep meter) for verifying the accuracy and operation of pulse type and DC holiday detectors

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Rolling Spring ElectrodesRolling Spring Electrodes

Steel pipe electrodes — assorted sizes available: 10 to 91 cm (4 – 36”) Rolling springs include two pre-installed spring couplers.

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Replacement Spring CouplersReplacement Spring Couplers

Thread onto rolling springs and attach to the Spring Connector

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Electrode AdaptorsElectrode Adaptors

Connect to spring and brush electrodes from other manufacturers

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Replacement BatteryReplacement Battery

Replacement Li-ion battery for the PosiTest HHD

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