Holiday Detector ISOTEST® 4S

... safe and sure

  • test voltage 10 - 25 kV, 5 kV steps
  • robust testing device for construction site operation
  • multi-stage sensitivity adjustment
  • patented automatic regulation
  • power reserves for the highest requirements
  • self-calibrating instrument
  • testing of dirty, damp and therefore slightly conductive surfaces
  • three grounding possibilities, including capacitive grounding (Phantom-Grounding)
  • no static charge of the text object
  • rapid battery change
  • low material stress thanks to short test pulses
  • safe grounding by automatic monitoring of the earth plug
  • emergency-off safety mode (optional)

Art.-No. 0141000010
Art.-No. 0141000001 – with emergency-off safety mode

Reserves of energy for the most demanding requirements by means of impulse voltage technology. The patented automatic regulation guarantees a precise test voltage. Its robust, hardwearing technology makes the ISOTEST® 4S suitable for the rough and tumble of everyday testing. Its ease of operation guarantees reliable test results in any situation on the construction site.


  • test voltage 10 - 25 kV, adjustable in steps of 5 kV
  • multi-stage sensitivity adjustment
  • acoustic and visual indication of porosity
  • emergency-off safety mode (optional)

Test voltage
10 - 25 kV, adjustable in steps of 0.5 kV

Voltage form
unipolar high voltage pulses

Pulse duration
10 μs

Pulse repetition frequency
25 Hz

Operation and indication via
graduated switch and status LED

Acoustic signals
up to 86 dB

Power Supply
lead acid rechargeable battery 6 V / 4.5 Ah,
battery life up to 9 hours

Dimensions (incl. instrument bag)
280 x 230 x 120 (mm)

Weight (incl. handle and instrument bag)
4.5 kg

Weight of rechargeable battery
0.9 kg

Length of high voltage cable to handle
1.5 m

Type of protection

Operating temperature
0 °C … +50 °C

Storage temperature
-20 °C … +50 °C

Revisions in the course of technical progress reserved.

  • ISOTEST® 4S test instrument complete with high voltage inspection handle including safety button
  • lead acid 6 V rechargeable battery – easy to change in its own compartment
  • charger 230 V / 50 Hz
  • grounding cable 10 m with clamping jaw and instrument plug for ground monitoring
  • robust instrument bag complete with carrying strap
  • operation manual and quick start guide
  • spare battery for safety button / fuses for rechargeable battery
  • works test report

ISOTEST® Industry Solutions / Test Kits

With the ISOTEST® industry solutions we offer you tailor-made packages fitted for the most diverse applications in the field of portable holiday detection.

more information

Testing Electrodes & Accessories

Benefit from our extensive accessories for holiday detectors.


  • testing electrodes
  • accessories for grounding
  • general accessories

more information

High Voltage Pulse Crest Meter ISOTEST® HV

  • accurate measurement of high voltages
  • testing of portable ISOTEST® holiday detectors and stationary ISOTEST® act holiday detector systems according to general rules and standards
  • easy to operate

more information

ISOTEST® Service for Holiday Detectors

You have opted for a high-quality ISOTEST® holiday detector because you attach great importance to safety and reliability – this also includes first-class service:


  • annual maintenance & calibration
  • troubleshooting / problem solving
  • inspection and repair by qualified personnel
  • seminars and training
  • laboratory tests with product samples

more information