Setting up safe test areas

It's important to make sure that anyone not involved with electrical testing work is kept free from risk. This can be done by confining testing work to a designated test area. In some workshops, it might be possible to set up a permanent workbench and test area, to which only the testers have access. Otherwise, unauthorised people should be prevented from approaching the equipment under test by physical barriers or other demarcation methods which form part of the test area boundaries.

Test areas can be: (a) a designated room built as a test area with special protection features and fitted with secure doors (possibly interlocked, depending upon the degree of risk) to prevent unauthorised access; (b) an area set aside in a workshop with some form of permanent barrier as a demarcation; (c) a work bench which might be designed as a test bench or be used for repairs and testing; (d) a designated work position within, or at the end of, a production line;

(e) a temporary area set up around equipment using purpose-built barriers as demarcation; (f) an area around fixed equipment, such as switchgear, or control gear, where skilled people are carrying out repairs, fault-finding or testing during maintenance work. In workshops where all employees have been adequately trained and instructed in safety practices and all unauthorised personnel are effectively excluded, local demarcation of the workbench or work area where testing is done may not be necessary.

All employees need to be aware that those who are carrying out testing should not be distracted by the interference of others who are not involved with the test in progress. Protecting the people doing the testing The measures that are used to protect the people doing the testing need to be effective to prevent them coming into accidental contact with dangerous exposed conductors.

This might be either a single-hand contact with a source of energy which has one of its supply conductors in electrical testing at work connected to earth, or another area of conducting surface. Class I equipment is in this category because the mains at source are earth referenced; so is electronic equipment where a large metal surface (or chassis) is connected to the source.

There is also a risk of injury from sources of supply which are not earth referenced and where accidental simultaneous contact with both poles of the supply is possible. Methods of reducing the risk of a shock from simultaneous contact with conductors include: (a) testing at reduced, non-hazardous voltages and currents; (b) using interlocked test enclosures in which the unit under test is contained; (c) using temporary insulation; (d) replacing covers which need not be removed for the purposes of the test, for example once supply connections have been made; (e) creating an area which is as earth free as practicable; (f) using isolating transformers connected to the mains supply; (g) using 30 mA RCDs. The following sections provide more detail about each of these protective measures.