Martindale PD690SX 50V/120V/230V/400V/690V AC Proving Unit with CALCHECK

  • Safely proves the operation of voltage indicators and test lamps up to 690V
  • Unique CALCHECK function for multifunction installation tests
  • Individual LED indicators matched to voltage indicator thresholds
  • Long battery life with low battery indicator
  • Includes MAG3 high strength magnetic hanger
  • Colour coded for voltage output

EAN: 5036162188510 SKU: MARPD690SX Category:


Safe electrical working requires the use of a voltage indicator that has been proven with a suitable proving device before and after use to ensure the instrument is working correctly in accordance with the Electricity at Work Regulations.

The PD690SX has all the capabilities of the standard PD690S proving unit plus a unique CALCHECK feature for verifying the performance of installation testers and 5 stepped voltage thresholds matched to common two pole tester thresholds.

The CALCHECK feature makes it easy to verify the insulation and low resistance ranges on 18th Edition multifunction instruments and single function insulation testers on-site, making it ideal for identifying potential calibration issues with a multifunction tester prior to certifying a new wiring installation or carrying out a condition report. It’s also a valuable procedure recognised by electrical contractor assessment bodies.

It’s easy to keep a record of periodic CALCHECK results and equipment serial numbers for assessments using the form in the user guide or downloading copies from this page.  The individual reference resistance test pads with nominal values of 0.5Ωand 1.0Ω for continuity measurements and 0.5MΩ and 1.0MΩ for insulation resistance make it simple to check and identify calibration drift and remain confident in your test results wherever you are working.

The proving unit output voltages are stepped with individual LED indicators for each voltage threshold from 50V to 690V matched to common two pole tester thresholds, ideal for identifying potential voltage tester calibration issues. On contact, the proving unit outputs the highest voltage first instantaneously checking all LEDs up to 690V on the tester and proving the tester for safe isolation use, it then steps down through each level automatically. At the end of the proving test, a low resistance appears across the terminals to verify the continuity function of two pole testers.

It’s good practice to match the output voltage of the proving unit with the voltage range of the instrument to be proved. The new S and SX Series simplify matching devices as they are colour coded with Martindale voltage indicators.


Output voltage 690/230/100/50V nominal
Output frequency 50Hz nominal
Output loading See datasheet
CALCHECK insulation test resistance 0.5MΩ (max test voltage 1kV)
1.0MΩ (max test voltage 1kV)
CALCHECK continuity test resistance 0.5Ω (max test current 200mA)
1.0Ω (max test current 200mA)
Temperature (Operating & Storage) -10°C to 40°C
Humidity (Operating & Storage) max. 70% R.H.
Altitude up to 2000m
Pollution Degree 2
Power 6 x 1.5V, AA alkaline batteries (IEC LR6, NEDA 15A)
Dimensions 150 x 80 x 35mm
Weight 350g approx. with batteries



Maximum Voltage Output690V AC440V AC690V AC
LED Voltage Thresholds690V50V, 120V, 230V, 440V50V, 120V, 230V, 400V, 690V
High Voltage LEDMultipleMultiple
Low Battery LED
High/Low Z Compatible
CALCHECK Resistance Values
Colour Coded to Match Voltage Indicators
Suitable forMultimeters, voltage testers & Drummond test lampsMultimeters, voltage testers & Drummond test lampsMultimeters, voltage testers & Drummond test lamps





CALCHECK Record Sheet