Accessibility statement

Electrical safety

The following describes the Department of Biology's policy and procedures for in-service testing of electrical equipment (portable appliance testing (PAT)).

The departmental policy & procedures cover all appliances connected to the mains by BS1363 13A plugs or IEC 60309 industrial connectors, including 3-phase. This includes all portable, moveable, transportable, hand-held, stationary and fixed appliances.  3-phase equipment is only tested in house if the appliance is connected to the supply via a plug.  External contractors are contracted by the Department to test equipment connected to the mains via a fused spur or hard-wired into an isolator.

Please note that the electrical safety of equipment brought in for demonstration or on loan is the responsibility of the supplier

Scheduled Testing Frequency

Schedule Test intervals are in accordance with the Institute of Electrical Engineers Code of Practice (IEE CoP), taking into consideration past experience of operating a testing system together with information on faults found. The frequency of testing will be monitored and reviewed on a regular basis. Equipment will be tested before a scheduled test if a visual user inspection indicates a problem, or if the equipment is repaired or modified.

Laboratory Equipment:

•    laboratory equipment (broad term used to describe most non-office equipment) will be tested on a 2-year cycle
•    all Class 1 and Class 2 items will receive a combined formal inspection and test - there will be no intermediate formal visual inspection *
•    detachable mains leads will not be tested or recorded as a separate item

Office Equipment:

•    all office equipment will be tested on a 5-year cycle
•    all Class 1 and Class 2 items will receive a combined formal inspection and test*
•    there will be no intermediate formal visual inspection.
•    detachable mains leads will not be tested or recorded as a separate item

Equipment Stored / Not in Use

•    will not be tested at the time of scheduled routine inspection
•    a label will be affixed to the equipment stating that it must be safety tested before future use
•    this non-scheduled testing will be carried out by the Infrastructure Team

Hand-Held Tools:

•    Hand-tools (drills, angle grinders etc.), e.g. those used in the Mechanical Workshop, will be tested on a one-year cycle* Only full tests are carried out as there is no meaningful advantage (in terms of the time a test takes) between a formal (i.e. recorded) visual examination and a full test.

Visual Inspection

Electrical appliances will be inspected for obvious damage or defects. Visual inspection of equipment will include checking:

  • for damage to the appliance which could affect the integrity of the insulation
  • for damage to the mains cable
  • that equipment has an appropriate mains fuse fitted in the plug
  • wiring on non-moulded plugs
  • for presence of adapted continental plugs:
    • Continental (Schuko) plugs on higher powered appliances, when used with UK adaptors, are undesirable; as a precautionary measure these will be replaced with UK 13A plugs when fitted to fridges, freezers and heated appliances.

Earth Bond Test

  • The earth bond Pass limit for a Class 1 test is 0.1ohm + R, where R is the resistance of the mains cable. The limit therefore depends upon the resistance of the protective conductor in the supply cord, which depends upon its length and cross-sectional area. The fixed limit will be of 0.1 for the appliance plus 0.1 for the cord giving a fixed limit of 0.2ohm. This corresponds with the fixed limit of the Seaward PrimeTest 100 and 250 PAT Testers
  • The pass limit for a detachable Class 1 (e.g. IEC type) cord set is also 0.2ohm
  • Test current will be either 1.5x the value of the fuse fitted in the plug, or between 20mA and 200mA

Insulation Resistance Test

Insulation Test Pass threshold is 1MΩ for Class 1 appliances, 2MΩ for Class 2 appliances.

Functional Tests

Functional tests will only be applied to equipment with an on / off light which may present a hazard if the light is not working e.g. laboratory hot-plate.

User checks

There is an expectation that all users of electrical equipment regularly check for damage/defects of equipment, leads and plugs.  All problems should be immediately identified to the Electronics Workshop.