FAQ's

Which is safer, Alternating Current (AC) or Direct Current (DC)?

Alternating Current (AC) and Direct Current (DC) have slightly different effects on the human body but both are dangerous above a certain voltage. The risk of injury changes according to the frequency of the AC and it is common for DC to have an AC component (called ripple). Someone with special equipment can measure this but the effect on a particular person is very difficult to predict as it depends upon a large number of factors. As a consequence you should always avoid contact with high voltage electrical conductors, regardless of the type of electrical current they are carrying. 

Everyone gets a ‘belt’ from electricity every now and then, don’t they?

No, not if they are careful and follow the simple rules to securely isolate electrical equipment and check it is dead before they start work. If you have received an electric shock but were not injured, then you are lucky. Next time a slight change in events may lead to a very different result. No one is immune to an injury from electricity. 

How do I know if my electrical equipment is safe?

The best way to find out if your electrical equipment is safe is to have it inspected and tested by a person who is competent to do so. This may be the original manufacturer of the equipment or his authorised service and repair agent. A reputable servicing company that deals with the type of equipment should also be competent to check its safety. Many of the potential faults in electrical equipment can be identified by a simple visual check, but electrical equipment should be tested more thoroughly on a regular basis. The test should be carried out often enough that there is little chance that the equipment will become unsafe between tests. Equipment for use in harsh conditions may need very regular testing whilst equipment in clean, dry, well-controlled environments may need less regular testing. It is good practice to make a decision on how often each piece of equipment should be tested, write down the decision, make sure the testing is carried out, and write down the results of the tests. 

How do I know if someone is competent to do electrical work?

A person can demonstrate competence to perform electrical work if he or she has successfully completed an assessed training course that has included the type of work being considered, run by an accredited training organisation, and has been able to demonstrate an ability to understand electrical theory and put this into practice. A successfully completed electrical apprenticeship, with some post apprenticeship experience is a good way of demonstrating competence for general electrical work. More specialised work such as maintenance of high voltage switchgear or control system modification is almost certainly likely to require additional training and experience.

What voltages are dangerous?

A wide range of voltages can be dangerous for different reasons. A very low voltage (such as that produced by a single torch battery) can produce a spark powerful enough to ignite an explosive atmosphere. Batteries (such as those in motor vehicles) can also overheat or explode if they are shorted. If a person comes into contact with a voltage above about 50 volts, they can receive a range of injuries including those directly resulting from the electrical shock (stopped breathing, heart etc), and indirect effects resulting from loss of control (such as falling from a height or coming into contact with moving machinery). The chance of being injured by an electric shock increases where it is damp or where there is a lot of metalwork.