Health & Safety Department

Electrical hazards

Guidance information produced by the Health and Safety Department which are relevant to electrical hazards.

The Electricity at Work Regulations, 1989, apply wherever the Health and Safety at Work, etc., Act, 1974, applies and wherever electricity may be encountered. The Regulations are primarily concerned with the prevention of danger from electric shock, electric burns, electrical explosion or arcing, or from fire or explosion initiated by electrical energy. The Regulations are supported by a Memorandum of Guidance (ISBN 0 11 883963 2) and a supplement "Electricity at Work" HSG 85-ISBN 0 11 882081 8 have been produced by the Health and Safety Executive (HSE). Schools where the use of electrical systems and electrical equipment forms a major part of the work of the school (area) should have a copy of these documents available, for relevant staff to consult.

The Regulations do not distinguish between systems of different voltages; they apply equally at all voltages and are constrained only by what might be appropriate to prevent danger or injury. The following Codes of Practice or guidance notes should be followed at all times.

General Safety Precautions

The risk of sustaining an electric shock can be reduced by adopting the following practices:

  • A suitable Permit-to-Work system should always be in place and operated, to ensure the effective isolation of hard-wired equipment before repair or maintenance work commences.
  • Due care must always be exercised when switching off main power supplies to ensure that only the intended circuits are isolated. Lock-off systems must be used, where necessary.
  • Switch off and withdraw the plug on items of portable electrical equipment prior to making any alterations or modifying any circuitry.
  • Do not handle any equipment with wet hands and do not work in close proximity to water supplies or other earthed metalwork where there may be a risk of putting one hand on earthed metal and the other on live equipment. If equipment is suspected of being live, switch off, and have its electrical status tested by a competent person. Record the test.
  • The external metal casing of electrical apparatus and associated cables and conduits must be earthed as a legal requirement. Water and gas pipes, however, must not be used as earth points. Such pipes must be effectively bonded, to ensure that they remain at an equal electrical potential. Checks should be carried out at least annually, to ensure that this continues to be the case.
  • On no account must a three-phase socket outlet be used to supply single-phase apparatus.
  • Where supplies to experimental equipment are obtained from terminals, these must be insulated and a control/emergency switch must be close by.
  • Standard types of electrical fittings, such as 3-pin plugs, sockets and switches, should always be used as specified by manufacturers and in accordance with good practice (e.g. switches must not be mounted upside down and single pole switches must not be wired into the neutral lead.)
  • If it is possible to do so, always use low voltage equipment.
  • The use of high voltage equipment must be strictly controlled, and suitable assessments of risk, and control features, prepared prior to use.


Codes of practice and guidance

Code of Practice

ES CoP001 Safe use of electrical equipment

Guidance documents

Safe use of electrical appliances

Inspection and testing regime of electrical appliances

Hazardous electrical equipment in laboratories