A foolproof, repeatable locking out process is vital to the safety of electricians so it is always important to have the necessary equipment to safely and securely isolate electrical circuits. Martindale manufacture a range of locks, tags, proving units and voltage testers which can check that a circuit is dead and prevent a third party from re-energising the conductor. These useful instruments are available in a range of kits and as individual items.
Martindale Voltage Testers
Voltage testers perform the vital task of proving that a circuit is dead before an electrician begins work. Typically, they will give the user a visual LED indication when voltage is present. The Martindale VI-15000 and VI13800 are both excellent examples of a simple voltage tester. Each will display voltage level and polarity via a series of LEDs and they have the additional benefit of being powered solely from the circuit under test - no batteries required!
Some models have an LED voltage bar-graph display or even a digital display and audible signal. In the Martindale range, such models include the VT12, VT25 and VT28. The two more advanced instruments offer additional tests such as continuity and single-pole phase whilst the VT28 even has a digital readout. However, these testers require batteries. All Martindale voltage testers indicate voltage up to 690V and have two poles to allow checks between phases, live, earth and neutral.
Martindale Proving Units
Proving units play a crucial role in the safe isolation process. It is necessary to verify that a voltage tester is working correctly before and after use so it must be brought it into contact with a known voltage source: a proving unit. Martindale provide a range of units with varying maximum voltages between 240V and 700V but the best proving unit for use with standard voltage testers is the Martindale PD690. Its large range is enough to test most voltage indicators and even test lamps and it has an LED to indicate when a tester is drawing power.
Locks and Tags
Proving units and voltage testers are needed to show that a switch has successfully isolated a circuit, but another crucial part of safe isolation is making sure that nobody can re-energise the system inadvertently. For this purpose, a wide range of locks of various shapes and sizes fit onto different circuit breakers and there is also a fuse carrier lock out. Martindale offer a secure padlock and a hasp can be used when multiple electricians are working on the same system. Tags are provided alongside a marker pen which clearly warn passers by that an electrician is at work and the operative can provide a contact number or estimated finish time.
Safe Isolation Kits
Several Martindale safe isolation kits are available from Test-Meter.co.uk. The LOKKITPRO sets contain useful locks, padlocks, cases and tags whilst the VIPDLOKPRO138 and VIPDLOKPRO150 kits feature proving units, voltage testers, tags, locks, padlocks, and tags in a handy carry case. They constitute a complete solution for locking out and verifying that circuits are safely isolated.