Section 46 in Tamil Nadu Combined Development and Building Rules, 2019
46. Electrical Transformer Rooms.
- Electrical rooms in Non High Rise Buildings and High Rise Building developments shall conform to the following:(1)Tamil Nadu Electricity Board. - Tamil Nadu Generation and Distribution Corporation (TANGEDCO) Standards:-(a)Indoor space required within the premises for installing floor mounted distribution transformer and associated switchgear.(i)An electrical room for accommodating the transformers and associated switch gears shall be provided at the ground floor, either within the built up space of the buildings or outside the buildings and within the premises of the buildings nearer the main entrance of the building. The associated switchgear shall be separated from the transformer bays by a fire-resisting wall with a fire resistance of not less than 4 (four) hours.(ii)The width of the approach road to the above said electrical room shall not be less than 3.0 meters.(iii)The electrical room with RCC roof shall have clear floor area 6m. X 4m. with a vertical clearance of 2.75m.(iv)Three sides of this room shall be covered with brick walls. The fourth side, towards the approach road shall be covered with M.S. Rolling Grill Shutter of width not less than 3 meters with locking facility.(v)The electrical room shall be fitted with 2 Nos. exhaust fans in the wall facing the approach road, one on either side of the shutter.(vi)The electrical room shall have raised cement flooring with cable duct of 450-mm. width and 750-mm. depth, all around inside the room and close to the exterior walls shutters. The flooring shall slope towards the cable duct. The cabled duct shall be covered with RCC slabs of thickness not less than 75 mm. (3 inches). The covered slabs shall flush with the cement flooring. The radius of curvature of the cable ducts at the turnings inside the electrical room shall not be less than one meter.(b)The open space within the premises for installation.A clear space of 10m. x 4m. or 5m. x 5m. open to the sky and having an approach road of width not less than 3 meters, up to the public road shall be provided within the consumer premises, preferably at the main entrance.(2)Directorate of Fire and Rescue Services Standards:(i)No transformer shall be located below the first basement or above the ground floor(ii)A sub-station or switch station with apparatus having more than 2000 liters oil shall not be allowed in the case of indoor transformer.(iii)The indoor transformer should preferably be housed in a fireproof room with walls and doors sufficient fire rating.(iv)The room in the ground floor of the basement housing the transformer shall have a free access to the outside.(v)There shall be a curb or a dwarf wall around the transformer so that oil spills if any, is contained within the curb. There shall also be a suitable drain with a '(vi)If in the basement, the transformers shall be adequately protected against fire by a high velocity water spray or a CO2 flooder of suitable capacity, depending upon the size of the transformer.(vii)The switch-gears, if any shall be housed in a separate room with suitable fire resistance walls.(viii)The transformers shall be located only in the periphery of the basement or ground floor, observing suitable clearances.(ix)DCP or CO2 portable fire extinguishers of a minimum capacity of 10 kg. shall be kept near the doorway housing the transformer.(x)All indoor transformers shall be subjected to periodic inspection and shall be replaced in good time so that there is no fire risk.(xi)The room shall be well ventilated so that the transformer remains cool.(xii)The room shall have emergency and automatic lighting with independent power supply.
