ELECTRICAL DISCONNECT SWITCHES (DS)
- Description: The Contractor shall comply with the provisions of Section 15001: General M&E Requirements. Fuse switches, where specified, shall comprise flush/surface mounted heavy-duty composite air break switches and fuse units complying with BS EN 60947-3 and fitted with fuses to BS EN 60269 and shall be rated and equipped as detailed. Composite units shall be contained within an enclosure of metal and shall be fitted with an earthing terminal or equivalent to enable the enclosures to be earthed irrespective of any means of connection such as is provided for attaching armouring or other metallic covering of the cable supplying the composite unit. Fuse switch shall be capable of making, carrying and breaking current under normal circuit condition, which may include specified operating overload conditions and also carrying for specified time currents under specified circuit conditions such as those of short circuit. The switch breaking capacity shall be related to AC 23 utilization category or other approved equivalent standard for 415V 3-phase 50Hz 4-wire operation for use on specified fault level and for service and site climatic conditions as described in Section 16020: Factory Built Assembly (FBA). BS EN 60269 compliant HRC fuses shall be provided as a mean of overcurrent/overload protective device to protect the switch. The maximum rated current of the fuse with regard to the prospective short circuit current in the actual circuit shall be mentioned. The fuse shall be connected after the switch so that a short circuit will not occur in the fuse-combination, thus for an expected fault to take place after the combination fuse switch unit. In the event of a fault this combination shall provide protection, permitting switching without, for example contact welding and preventing separation of main contacts in case of fault occurring during running. The combination fuse switch unit shall be housed in an enclosure so constructed that the cover cannot be opened until the switch is fully opened and the construction shall be such that when the cover is opened a competent examiner can override the interlock and operate the switch. After such operation the cover shall be prevented from closing with the switch position indicator in a false position. Switches shall be provided with mechanical ON/OFF indicators and operating handles. Means shall be provided for locking the switch in the OFF position only.
- Standards: Local
- Location: Abu Zabi
- Categories: Fire Protection, Architecture, Structure, Mechanical, Electrical, Plumbing, Generic
- Sub Categories: Architecture
- Posted: February 3rd, 2022, 10:53 am
- FUSE SWITCHES
- ISOLATOR
- FUSES
- CHANGEOVER SWITCH
- TRANSFER SWITCH ATS/MTS/BYPASS
- SOURCE TESTS
