6 minute read
Electrical safety
Safe isolation: what are the rules?
How can gas engineers achieve safe isolation and why do they need to do so? Paul Wilson, UK & Ireland sales manager for Martindale Electric, answers some of your most frequently asked questions.
When it comes to gas safety, you are rightly expected to be more than just competent; you should be experts in your field. But there are plenty of other safety-related issues that you also have to be aware of. One of these is becoming ever more prominent: electrical safety.
But just being aware of issues around electrical safety is no longer good enough; you have to have both the knowledge and competence to safely isolate the electrical supply to a gas appliance that uses electricity.
What is safe isolation and why is it necessary?
Electricity is the cause of approximately 1,000 accidents at work every year – many more incidents inevitably go unreported – and 16 per cent of all workplace fatalities are linked to electricity.
With modern gas installations and appliances requiring more electrical connections than ever before – making up to 15 per cent of installation work – gas engineers are at greater risk from electricity. HSE provides clear guidance that live work should never be undertaken where there is the option to work electrically dead, and so establishing an effective electrical safe isolation procedure is critical to keep you safe.
The procedure involves de-energising the relevant circuits, isolating them properly before you start any work and, just as importantly, proving that they are electrically dead. The only exceptions allowed are when fault-finding on the installation, in which case appropriate care must be taken at all times.
What are the rules regarding safe isolation and how have they changed?
For newcomers to the gas industry, safe to touch, safe isolation and proving that a gas appliance is electrically dead are already part of the training. The important change comes from recognising the increased risk that gas engineers face.
It means that all Gas Safe engineers must have the technical knowledge and competence to undertake safe to touch, safe isolation and proving electrically dead procedures before starting work on any gas installation/ appliance that has a connection to a 230V electrical supply.
This has been in effect since July 2020 and, by July 2025, all gas engineers will be required to self-validate that they have the knowledge and competence to safely isolate the electrical supply to a gas appliance that uses electricity; it could be as simple as signing a declaration stating this.
How can safe isolation be achieved?
Wherever possible and practicable, it is vital that gas engineers should work on dead circuits. Ensuring that you are not exposed to danger when working on or near live electrical systems requires a combination of effective safe isolation procedures and equipment that meets the latest standards, including HSE GS38 guidance notes(1). Failure to use the right equipment can result in a circuit remaining live – and the consequences can be fatal.
Take the time to identify the risks and introduce steps to ensure that all equipment is electrically safe before you start work.
Proper work planning and using the right tools for the job will help you to avoid incidents.
How can I be sure a circuit is actually dead?
Locking off the circuit correctly is an important step in the procedure, but it’s not enough to assume that the circuit is subsequently dead because a particular isolation device has been placed in the OFF position. Although the circuit may be locked off, the neutral conductor can become live if an energised load on another circuit is connected to it.
And it’s not uncommon for circuits to be mislabelled, which can be particularly dangerous because it provides no certainty that the correct circuit is actually locked off.
Guidance from charity Electrical Safety First states that before carrying out any work on a circuit, engineers should use a dedicated voltage indicator and >
Safe isolation: what are the rules? (continued)
proving unit to prove the circuit is indeed dead. While this may sound obvious, we know from experience that there are still far too many instances where engineers might try to use a known live source to test a voltage indicator.
The problem is that the known live source may only light some of the LEDs on the tester, whereas a proving unit will ensure that all the LEDs on all ranges are working, eliminating any uncertainty.
A further issue is that a known live source may not be conveniently available, increasing the risk that the voltage indicator is not actually proved to be operating correctly.
What equipment can I use?
You can comply with the standards by using fail-safe voltage indicators and proving devices that have been engineered specifically with safety in mind and are easy to use.
When choosing a voltage detector that complies with GS38, make sure that it is made to BS EN 61243-3.
It should be designed without batteries or switches – which could lead to false indication – and the voltage level readings should be clearly visible. It should also be durable as, let’s face it, equipment gets knocked around. Look for a unit that is robust to prevent it getting damaged in a tool case, and that has heavyduty finger guards and doubleinsulated cable.
I also recommend choosing a unit dedicated purely to detecting voltage; in other words, avoid using multimeters, as recommended by HSG 85. A multimeter measures multiple electrical properties, such as voltage, resistance and current. The problem is that they introduce the potential for human error, making it too easy to select the wrong range. In addition, they rely on battery power; if the batteries are flat, then a false “dead” reading will be given on a live circuit. The position is similar with non-contact voltage detectors; while these are frequently used to detect live cables, they cannot reliably prove dead or confirm the safe isolation of a circuit.
You may want to consider investing in complete safe isolation kits, which bring together all the necessary equipment to prove dead and lock out the circuit being worked on. These kits generally feature a GS38 industry standard voltage indicator, proving unit and locking off devices in a combination carry case, which also helps prevent accidentally leaving any of the equipment behind. ■
www.martindale-electric.co. uk/product-category/safeisolation-voltage-indication
(1) Electrical test equipment for use on low-voltage electrical systems, www.hse.gov.uk/pubns/ books/gs38.htm
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