Introduction section1: general requirements
UNDER VOLTAGE (U.V.) RELAYS WITH AUTO-RESET TIMER
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- SECTION - 9 CONSTRUCTION SITE INSTALLATIONS
UNDER VOLTAGE (U.V.) RELAYS WITH AUTO-RESET TIMERAll air-conditioners or air-conditioning units/plants/equipment installed within the consumers’ installation shall be provided with Under Voltage (U.V.) relays with fixed voltage cut off setting at 75% of the nominal supply voltage, within 0.2 seconds and auto- reset timer with adjustable time setting between 5 and 10 minutes. The circuit breakers/contactors associated with the under voltage (UV) relays, shall have 'auto closing' facility (motorised operation) to restore supply to the chillers/air conditioning units, after normalization of supply voltage, when the relay is reset automatically. The auto-reset timer of the U.V. relays shall be set at values specified in the schedules, approved by DEWA, to suit individual installation. Necessary provision for sealing may be incorporated in the relay to restrict access for adjustments of the setting. The U.V. relays with auto-reset timer shall normally be incorporated within the respective air-conditioning unit/equipment or in their control panels. For normal air-conditioners, provision of U.V. relays with auto-reset timer within the consumers’ distribution board shall be permitted for individual or group of units. Prior approval shall be obtained from DEWA on every such application. The U.V. relays with associated controls shall be checked and maintained regularly. SECTION - 9 CONSTRUCTION SITE INSTALLATIONSGENERAL Application for temporary power supply for construction purposes shall be submitted through online getting electricity, under category ‘Construction Supply’, well in advance of the power requirement. Temporary power supply shall be permitted for construction purposes subject to terms, conditions, fees, tariffs and instructions issued by DEWA from time to time. The consumer shall comply with the safety requirements specified for permanent installation, in addition to the specific requirements on installation at construction sites recommended in this section of the Regulations. Every assembly for the distribution of electricity on construction sites shall comply with the requirements of BS 4363 and BS EN 60439. Equipment shall be identified and be compatible with the particular supply from which it is energized and shall contain only components connected to one and the same installation. Cable shall not be installed across a site, road or walkway unless adequate protection of the cable against mechanical damage is provided. All cables used on construction sites shall have a metal sheath and/or armour which shall be effectively earthed and continuous. Every wiring system shall be so arranged that no strain is placed on the terminations of conductors unless such terminations are designed for this purpose. Each assembly for construction sites shall incorporate suitable devices for switching and isolation of the incoming supply. Circuit breaker for isolating the incoming supply shall be suitable for securing in off position by padlock or the device shall be installed inside a lockable enclosure. Safety and standby supplies shall be connected by means of devices arranged to prevent interconnection of the different supplies. The metering cabinet, distribution board/s or any wiring installations, installed outdoor, shall be of weather proof type IP 65 Download 2.29 Mb. Share with your friends:
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