Introduction to Health and Safety at Work

equi-
potential bonding
of all conductors to earth. This applies 
to gas, water and central heating pipes and other devices 
such as lightning protection systems. 
Supplementary 
bonding
is required in bathrooms and kitchens where, 
for example, metal sinks and other metallic equipment 
surfaces are present. This involves the connection of a 
conductor from the sink to a water supply pipe which 
has been earthed by equipotential bonding. There have 
been several fatalities due to electric shocks from ‘live’ 
service pipes or kitchen sinks.
12.2.2 Some 
defi nitions
Certain terms are frequently used with reference to elec-
tricity and the more common ones are defi ned here.
Low voltage
– a voltage normally not exceeding 600 V 
ac between conductors and earth or 1000 V ac between 
phases. Mains voltage falls into this category.
High voltage
– a voltage normally exceeding 600 V ac 
between conductors and earth or 1000 V ac between 
phases.
Mains voltage
– this is the common voltage available 
in domestic premises and many workplaces and is nor-
mally taken from three pin socket points. In the UK it is 
distributed by the national grid and is usually supplied 
between 220 V and 240 V, ac and at 50 cycles/s.
Maintenance
– a combination of any actions carried out 
to retain an item of electrical equipment in, or restore it 
to, an acceptable and safe condition.

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Electrical hazards and control
189
Testing
– a measurement carried out to monitor the con-
ditions of an item of electrical equipment without physic-
ally altering the construction of the item or the electrical 
system to which it is connected.
Inspection
– a maintenance action involving the careful 
scrutiny of an item of electrical equipment, using, if neces-
sary, all the senses to detect any failure to meet an 
acceptable and safe condition. An inspection does not 
include any dismantling of the item of equipment.
Examination
– an inspection together with the possible