Civil Engineering Reference
In-Depth Information
Table 8.4
Electrical safety on construction sites
Equipment/application
Voltage
User check
Formal visual
Combined
inspection
inspection
and test
Battery-operated power tools and torches
Less than 25 volts
No
No
No
25 V portable hand lamps (confi ned or
25 volt secondary
No
No
No
damp situations)
winding from transformer
50 V portable hand lamps
Secondary winding
No
No
Yearly
centre tapped to
earth (25 volt)
110 V portable and handheld tools,
Secondary winding
Weekly
Monthly
Before fi rst use
extension leads, site lighting, movable
centre tapped to
on site and then
wiring systems and associated switchgear
earth (55 volt)
3 monthly
230 V portable and handheld tools,
230 volt mains supply
Daily/every shift
Weekly
Before fi rst use
extension leads and portable fl oodlighting
through 30 mA RCD
on site and then
monthly
230 V equipment such as lifts, hoists and
230 volt supply fuses
Weekly
Monthly
Before fi rst use
fi xed fl oodlighting
or MCBs
on site and then
3 monthly
RCDs Fixed
Daily/every shift
Weekly
*Before fi rst use
on site and then
3 monthly
Equipment in site offi ces
230 volt offi ce
Monthly
6 monthly
Before fi rst use
equipment
on site and then
yearly
prudent that the main or principal contractor ensures
that the fi tter is from an approved and registered list.
A large proportion of hot work is undertaken utilis-
ing LPG cylinders and thus controls in relation to the
cylinders are included within the section on hot work.
➤
Where protective fl exible coverings are installed they
are installed by a competent person to ensure that
appropriate overlapping is achieved
➤
Electrical supplies may be intrinsically safe depend-
ent upon the hot work processes being undertaken,
e.g. the use of LPG
➤
Storage of combustible materials within the fab
shop should be prohibited
➤
Extraction systems to remove airborne contam-
inants should be installed
➤
Detection systems (heat or rate of rise) may be
installed
8.4.15 Hot work
Ideally, the need for hot work should be eliminated by
the use of alternative methods, e.g. bolting component
parts rather than welding. However, where this cannot
be achieved a dedicated area remote from fuel sources
such as combustible waste materials, fl ammable vapours
and combustible parts of the building structure should
be considered.
It may be possible to establish a 'safe haven' by
erecting a temporary fabrication (fab) shop on site where
the hot work may be undertaken. This will also assist in
the management of ill-heath issues such as weld fumes
as dedicated LEV can be introduced into the fab shop.
These temporary fab shops comprise:
➤
Fire fi ghting equipment (fi re extinguishers) should be
provided.
Hot work permits as part of a 'permit to work' system
may be adopted for work within the fab shop. However,
such systems must be adopted on all other areas of site
unless there is minimal risk of damage to surrounding
property.
Hot work permits are formal management docu-
ments which support the control of the safe systems of
work or methods of work. Permits themselves should not
be issued as general or blanket authorisations as this can
lead to complacency when permits are issued as a matter
➤
Non-combustible fl oors or ceilings or alternatively
fl oors and walls with fl exible protective coverings
that conform to LPS1207
