Martindale CP501 Classic Check Plug 230V Socket Tester

  • Quick & easy testing of socket wiring with the UK’s favourite check plug
  • Detects 28 fault conditions
  • Three bright LEDs with clear & simple fault codes on the plug
  • Tough sculpted design for easy removal

EAN: 5036162183003 SKU: MARCP501 Category: Tag:


With over 2 million of these socket testers sold, the Martindale CP501 is the most popular socket tester available. The classic check plug is a quick and easy way to ensure that 13A sockets are correctly wired, indicated by 3 bright long life LEDs.

Wiring faults are indicated by one or more of the LEDs failing to illuminate, with the pattern of lit LEDs indicating the type of fault detected. This fail-safe system means that any LED not lit indicates a fault.
The robust ABS housing has a sculpted shape for easy removal and there is a look up chart on the tester for quick fault diagnosis.

The plug induces less than 5mA of earth leakage, well below RCD trip thresholds.

Detects 28 fault conditions.



Operating voltage range 230V
Frequency range 30-70Hz
Power consumption <2W
Temperature range -10 to 40°C at max, 60% RH
Supply from mains
Open Earth If earth resistance >50kΩ nom at 230VAC nom
Open Neutral If neutral resistance >50kΩ nom at 230VAC nom
Complies with BS EN 61010-1
Dimensions 65 x 65 x 47mm
Warning Like all other standard socket testers, these units cannot detect common earth and neutral or earth neutral reversal.