Steve Dunning, Managing Director of Martindale Electric, highlights why safe isolation is the foundation of electrical safety. Without it, anyone working on or near live systems risks serious injury, or worse.
Despite clear regulations and well-established procedures, incidents still occur where circuits are not safely isolated. In many cases, the cause is simple: the right equipment wasn’t used, or the correct process wasn’t followed.
Ensuring that electrical equipment and circuits are proven dead is not just good practice; it is essential to safeguarding people and assets. A robust approach to safe isolation significantly reduces the risk of electricity-related injuries and fatalities in the workplace.
Choosing the Right Equipment
Selection and use of the right equipment is one of the most important parts of the procedure. Firstly, a voltage indicator with the means to prove it is operational, usually by using a dedicated proving unit. Secondly, lock off items suitable for the circuit being tested and signage to warn others. Failure to use the correct equipment and procedures can result in a circuit inadvertently remaining live.
Locking Off
Locking off devices are either supplied as individual items or, more generally, as kits. There are many kits and combinations available. Most typically include MCB and breaker locks, a padlock with a unique key or combination, a hasp for multiple users, and a range of tags and warning labels. The isolation device should be locked securely in the “off” position, and a warning tag attached. Only the person performing the work should hold the key or code, this prevents accidental re-energisation by others. Once the breaker is locked off, the job isn’t complete until the circuit is verified dead.
Proving Dead
This step is critical. Circuits are often mislabelled (or unlabelled altogether), so you cannot assume power is off simply because a switch has been thrown.
Best practice is to use a dedicated voltage indicator with a compatible proving unit. Importantly, the tester must comply with BS EN61243-3 and work without batteries, otherwise there’s a risk of a flat battery giving a false “dead” reading.
The correct process is straightforward:
Test your voltage indicator on a known source
Test the circuit.
Re-test the indicator on the known source to confirm it is still working.
Whilst you can use a known live source to test your voltage indicator, a much safer method is using a dedicated proving unit matched to the indicator being used. The reason is that the known live source may only light some of the LEDs on the tester, whereas a proving unit will ensure that all LEDs on all ranges are working, again safeguarding against incorrect readings due to a fault. In addition, there is not always a suitable live source nearby and a dedicated proving unit is faster and safer.
Guidance advises against the use of both multimeters and non-contact devices for proving dead. Multimeters are not suitable for the proving dead process as it is easy to select the wrong range and a multimeter relies on battery power to function fully, there is a high risk of making a false “dead” reading on a live circuit. Non-contact voltage detectors also require a battery in order to work and are often sensitive to other signals, such as static electricity. It’s also not possible to prove they are working correctly with a standard proving unit.
Isolation, locking off, and proving dead are all essential — not just for the worker, but for everyone else who may be on site.
Martindale ALIVE
To reinforce these principles, Martindale Electric created the ALIVE campaign — a simple, memorable acronym highlighting the five non-negotiable steps that protect workers and save lives.
ALIVE: Five Steps to Safe Isolation
A – Approved Kit
Only use equipment that meets legal safety standards (BS EN61243-3, BS EN61010).
L – Lock Out
Lock out & tag out (LOTO)- Identify the point of isolation, lock it off securely, and attach warning tags.
I – Initial Prove
Check your voltage indicator against the proving unit before starting.
V – Voltage Test
Test the circuit with your voltage indicator to confirm it is not live.
E – Ensure
Re-test your voltage indicator on the proving unit to make sure it is still working.
By streamlining electrical safety into these five simple steps, the ALIVE process makes it easier for everyone to remember the process, work safely and return home at the end of the day.
Safe Isolation Saves Lives
Safe isolation is neither difficult nor expensive, but it is essential. With standards, guidance, and affordable kits widely available, there is no excuse for taking shortcuts.
Industry resources, such as Best Practice Guide 2 from Electrical Safety First offer additional practical advice and reinforce the importance of using test lamps, proving units, and compliant voltage detectors when proving dead.
The message is clear: safe isolation saves lives. By using the right equipment and following the correct procedure every time, we can reduce accidents and protect both people and property from the dangers of electricity.
For further information visit: https://martindale-electric.co.uk/ALIVE/
