Martindale simplifies industrial socket testing
When properly specified, socket testers provide a fast and effective solution to identify potentially unsafe installations and wiring faults of power outlets. They can be particularly useful as a service tool prior to installing new plant and equipment. Clearly socket testers are not an alternative to the full verification of wiring installations, however as a first line indicator they are an essential tool for all maintenance teams.
Martindale’s range of industrial socket testers
You may well be familiar with the Martindale Buzz-IT and Check Plug, the UK’s favourite test plugs for polarity and fault checking of 13A wall sockets, but did you know Martindale offers a complete range of industrial socket testers for both single and 3 phase systems.
- The CP and BZ Series for single phase industrial sockets – 230V & 110V models for both 16A and 32A sockets
- The PC Series for 3 phase supplies – 16A, 32A, 63A models for 4 and 5 pin configurations
Single phase industrial sockets
The Martindale CP201 Industrial Socket Tester and BZ201 Industrial Socket Testers are industrial versions of classic check plug, both available with either a 16A or 32A plug to the BS EN IEC 60309-1 standard. Both are capable of identifying 28 fault conditions. The BZ201 has an audible sounder to confirm that the wiring is correct. This is particularly useful when checking sockets that are not easily visible or in difficult to access locations. The audible indication can also be used as a basic fuse finder. When the correct fuse is pulled the buzzer stops.
Other products in the range include the CP301 Industrial Socket Teters for use on 110V centre tapped circuits fitted with a yellow 110V 16A or 32A CT plug. Fault indications include Line 1, Line 2 and centre tap faults, plus Line 1 or 2 centre tap reversal.

Understanding socket tester functions and limitations
Before carrying out any socket testing it’s important to understand what they are capable of and the different types available. All socket testers check that the earth, live and neutral are the right way around (called polarity testing). Some offer added features – they may include a buzzer in addition to LEDs to indicate a good socket or they may show a combination of indicators to identify which particular fault type is present. There is one fault that a socket tester and indeed no other piece of equipment can easily find – the swapping of the Earth and Neutral wires. This is because the earth and neutral are common at the substation, (if not closer), so electrically they are indistinguishable.
On plugging in the tester, faults are instantly indicated by one or more of the LEDs failing to illuminate, with the pattern of lit LEDs indicating the type of fault detected. Common fault conditions can be quickly identified from the look up chart displayed on the front of the label. This approach is fail-safe in the unlikely event of any the LEDs failing to operate.
Three-phase industrial socket testers
For 3 phase supplies, the PC104 and PC105 three phase industrial socket testers can be used for identifying 7 wiring condition faults and also confirm the phase rotation sequence with bright LED indication.
The range of 3 Phase Industrial Socket Testers cover 4 and 5 pin socket configurations and 16, 32 and 63 amp versions are available. The testers are enclosed in a tough rubber holster to withstand harsh of on-site environments.

Martindale – Pioneers in Socket Testing
With both simple and advanced testing capability, Martindale’s socket tester range is ideal for domestic, commercial and industrial applications
Discover Martindale’s comprehensive range of socket testers.








