This arrange-
ment limits the voltage earth which recognized safe
FIGURE 14.Electrical installations and wiring systems
325
The British Standards Code Practice 1017, The Distribution Electricity
on Construction and Building Sites, advises that protection against earth
faults may obtained first providing low impedance path, that
overcurrent devices can operate quickly described Chapter 12, and
secondly fitting RCD addition the overcurrent protection device
(IEE Regulation 704. The supply usually provided a
reduced voltage distribution unit which incorporates splashproof
sockets fed from centre-tapped 110 transformer.313, 704. When the local
electricity company provides the supply, the incoming cable must ter-
minated waterproof and locked enclosure prevent unauthorized
access and provide metering arrangements.75kW such cranes and lifts.8 tells that reduced low
voltage strongly preferred for portable hand lamps and tools used on
construction and demolition sites.3.10).3.
The source supply for the temporary installation may from petrol
or diesel generating set from the local supply company.10 and 411. construction site installation should
be tested and inspected accordance with Part the Wiring Regulations
every months throughout the construction period. The 17th edition the IEE Regulations
considers construction sites very special locations, devoting the whole of
Section 704 their requirements.410. These supplies must wired armoured cable unless run
inside the site offices.
(a) (b)
Safety First
Construction sites
● low voltage or
● battery tools must used.
IEE Regulations 704.40
110 distribution unit and cable connector, suitable for construction site electrical supplies:
(a) reduced-voltage distribution unit incorporating industrial sockets 60309 and (b) industrial
plug and connector.
● 230 single phase for supplies items equipment which are
robustly installed such floodlighting towers, small hoists and site
offices.410.
The distribution electrical supplies construction site would typi-
cally follows:
● 400 three phase for supplies major items plant having rating
above 3.
.
● 110 single phase for supplies all mobile hand tools and all
mobile lighting equipment. These supplies must wired
in armoured cables
