Construction site electrical supplies

V distribution unit and cable connector, suitable for construction site electrical supplies ... 

Figure 1.29 110 volts distribution unit and cable connector suitable for construction site electrical supplies (a) reduced-voltage distribution unit incorporating industrial sockets to BS 4343 (b) industrial plug and connector. 

In 1993 epoxy- lysulphide based coatings were used to coat two 250 MW thermal power projects at Dhanu, about 100 km north of Bombay. The site is on the coast, less than 1 km from the sea and as such the nature of the local atmosphere is highly corrosive, with continuous sea breezes, and the soil is saturated with marine salt. The coating has shown satisfactory performance (Figure 10.7) (Morton International, undated c). This project was constructed under the control of Bombay Suburban Electricity Supply Co. Ltd (BSES). 

In the three years from 1942 to 1945, the US opened thirteen new chemical warfare plants. The most ambitious was the 60 million Pine Bluff Arsenal in Arkansas. Construction work began on 2 December 1941, five days before Pearl Harbor, on a 15,000 acre site. Within eight months an army of labourers and construction experts had laid miles of road and railway track, built factories, storage depots, laboratories, shops, offices, a hospital, a fire station, a police building, water, gas and electricity supplies and a telephone exchange. 

On Friday 25 April 1986, the night shift on the station consisted of 176 operators on duty on Reactors 1-4, together with 268 construction workers on Stage 3 site. Reactors 1-3 were at full power and Reactor 4 was at low power, supplying steam to T/A 8 prior to the turbine rundown test to determine the security of electrical supplies to essential plant if the steam supplies were shut off from the turbine. The sequence of events leading to the destruction of Reactor 4 has already been described in Section 3. 

Temporary electrical supplies provided on construction sites can save many man hours of labour by providing the energy required for fixed and portable tools and lighting which speeds up the completion of a project. However, construction sites are dangerous places and the temporary electrical supply which is installed... 

The distribution of electrical supplies on a construction site would typically be as follows ... 

Temporary electrical supplies on construction sites can save many person-hours of labour by providing energy for fixed and portable tools and... 

Electrical supplies on construction sites for portable tools should... 

Electrical hazards are covered in detail in Chapter 14, and all the control measures mentioned apply on a construction site. However, due to the possibility of wet conditions, it is recommended that only 110 V equipment is used on site. If mains electricity is used (perhaps during the final fitting out of the building), residual current devices should be used with all electrical equipment. Where workers or tall vehicles are working near or under overhead power lines, either the power should be turned off or goal posts or taped markers used to prevent contact with the lines. Similarly, underground supply lines should be located and marked before digging takes place. 

Subsection 611-03 recognises that many installations do not have isolating switches and are fed from the supply company s combined cut-out, neutral link and sealing box on the end of the service cable, so in such cases electrical maintenance is restricted to qualified persons. The restriction does not apply to relamping if an isolating switch is available. Supplies are sometimes taken from street furniture to feed temporary installations such as market stalls, Christmas decorative street lighting and small roadworks. Subsection 611-06 requires no impairment of the safety of the permanent installation so it must not be overloaded and the connection must be safe. The temporary installation should comply generally with section 604 for construction sites. 

BS 4363 Distribution units for electricity supplies for construction and building sites, was issued in 1968, and was amended in 1992 for compatibility with BS EN 60439-4 1994. This standard specifies the equipment. In 1969 BS CP 1017 appeared. This was the code of practice which describes how the BS 4363 apparatus was to be installed and used. This code was subsequently amended and renumbered as BS 7375 1996. See also HSE guidance booklet HS(G)141 - Electric Safety on Construction Sites. 

Every year there are thousands of incidents involving damage to buried cables, some of which result in burn injuries and a few (typically one or two) are fatal. Most of the incidents occur during street works where utility companies, construction companies and local authorities carry out excavations in the highway and damage an electricity supply company s underground mains. Other incidents take place on construction sites and other private property and involve a supply company s service cables or mains, or distribution cables belonging to the site occupier. 

Both temporary and permanent electrical supply installations should be installed in accordance with the latest addition of BS 7671 (lEE Wiring Regulations and the Electricity at Work Regulations 1989). Installations, particularly if of a temporary nature, for example in construction works, must be inspected regularly and tested at intervals no greater than those specified by the installation company. It should be noted that if temporary installations are in position for a greater period than 3 months on a construction site then they should be subject to test in line with HSE guidance every 3 months or when they have been altered. 

As with all electrical supplies and installations those relating to construction operations should be installed in accordance with the lEE Wiring Regulations. Arrangements should be established that all contractors on site ensure that their electrical equipment is portable appliance tested in accordance with HSE s guidelines in HSG141. The frequency of test differs from that in an office, hotei, etc. environment in that the arduous environment in which the equipment is used reduces the time frames between tests as detailed in Table 8.4. 

The facilities for laborers (blue collar) are provided by construction companies at construction sites and in line with local rules and regulations. Companies provide furnished accommodations called labor camps they are not for families. Labor camps are provided with electricity, a water supply and food facilities (Figs. 47.10... 

Underground services must be located and marked where applicable, using plans, etc. Overhead power lines should be disconnected, but otherwise fenced/signed. Water, gas and electricity supplies must be disconnected. Fall prevention and protection techniques will be required in accordance with the Construction Regulations hierarchy of control. PPE required by assessments must be provided and worn. Dust should be controlled by a combination of damping down, housekeeping, work methods and local exhaust ventilation. Defined noise protection zones, barriers and work rotation combine to tackle noise above the action levels. Site boundary noise output may be the subject of local authority controls. 

BEC/Loss Prevention Council Code of Practice Fire prevention on construction sites BS4363 1991 - Specification for distribution assemblies for electricity supplies to construction... 

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