Activities Involving Electrical Apparatus

Activities Involving Electrical Apparatus
The principle hazards associated with the use, maintenance and repair of
electrical equipment are:
a. Electric shock by contact with live or charged conductor;
b. Burns by contact with live or charged conductor, exposure to thermal or
ultraviolet radiation from a high energy arc, or to high frequency
electromagnetic radiation.
c. Fire and explosions by the ignition of gases or vapours by electric arcs,
sparks, heating appliances, leakage currents, overloaded conductors or
static electricity;
d. Electric shock by contact of equipment with water.
Risk Factors:
 Work on or in close proximity to any supply system, equipment or cable
with exposed live conductors at a voltage greater than 50V ac or 100V dc;
 Use of electrical equipment with conductors at voltages grater than 650V.
 Use of equipment in damp or humid environment or where equipment may
come into contact with any conducting liquid (e.g. equipment out-of doors,
electrophoresis apparatus, chemical procedures, distillation, reflux)
 Use of any non-explosion protected equipment, even operating at very low
voltages or supplied from batteries, likely to come into contact with any
flammable dust, gas or vapour;
 Use of hand-held equipment (e.g. tools, floor cleaners and vacuum
 Use of equipment connected to a temporary installation;
 Use of multiple socket adaptors, distribution boards and coiled flex cable
drums or reels, or other extension cables without adequate overload or
excess current protection;
 Use of equipment which is damaged, including equipment with missing or
removed covers or panels, equipment with damaged flexible cables or
plugs, equipment where the outer supply cable sheath is not securely
gripped at the plug or the equipment terminals or the use of equipment
terminals or the use of equipment with temporarily taped joints in the
supply cable;
 Use of equipment that has adaptors for European plugs.
Risk Control Measures:
1. Connect equipment to a mains supply system that accords with IEE Wiring
Regulations (BS7671) for safety which is installed and tested only
contractors approved by the QMUL engineer;
2. Use portable equipment and appliances supplied at safe extra low voltage
(below 50V ac) or reduced voltage (110 V centre tapped system) where
3. Equipment for use in adverse environments (dusty, wet, hot, corrosive)
should incorporate special protection, e.g. residual current devices for
equipment used in a wet environment, to be protected against the ingress
of dust or moisture;
4. Use equipment and cables with conductors and terminals which are
electrically insulated to prevent shock and short circuits and protected
against physical damage;
5. Use double insulated (class II) rather than earthed (Class I) equipment
where practicable. Earthed equipment should have low resistances
(<0.5ohm) protective earth conductor (colour coded green/yellow) which
must be securely connected to earth pin terminal of the plug connector;
6. Replace damaged cables or repair damaged section using BS or
equivalent approved connection or coupling device;
7. Protect equipment and cables against excess currents by the use of
correctly rated circuit fuses or breakers, moulded plugs should not be
8. Provide a switch or isolator near to each fixed item of equipment and
ensure that all mains circuit and supply switch areas are accessible and
9. Isolate or disconnect equipment from any supply when it is not being used
or while it is being repaired or subject to internal cleaning or modification.
Remove the circuit fuses or isolators or padlock the isolator in the offposition before working on any supply circuit;
10. Do not work within 1 metre of any equipment or installation with
unprotected or exposed live conductors at more than 50V ac or 100V dc;
11. Report damaged or faulty equipment or installations to the responsible
supervisor or line manager who will make arrangements for its repair or
replacement. Do not use any damaged or faulty equipment or appliances
with damaged cables and plugs. Disconnect and label any damaged item
“Do not use” and refer it to a competent person for repair;
12. Arrange for the maintenance for safety of equipment by appropriate
inspection and where necessary testing.
13. European plugs on equipment and apparatus should be replaced by a
competent person for the British standard equivalent (BS 1363)
Persons at Special Risk:
Those working with high voltages (>650 V), those undertaking live working and
those working with hand-held equipment outdoors or in wet conditions.
Health Surveillance:
No special requirements
This assessment is not adequate for work on equipment or installations with live
exposed conductors at dangerous voltages and the use of electrical equipment in
flammable or very dusty environments.
Relevant Statutory Provisions and Other Guidance:
Electricity at Work Regulations 1989
Memorandum of guidance on the Electricity at Work Regulations 1989, HSE
BS 7671, the IEE Wiring Regulations
The safe use of portable electrical apparatus, HSE, PM32
Electrical Safety and You, HSE indg231