Shop Practice with Electrical Code: Miscellaneous Selected Provisions Jayson Bryan E. Mutuc, REE, RME BSEE-PUP MSEE, Major in Power Systems -MIT (candidate)
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Selected Provisions to be discussed • Use of Extension Cord • Clearance of OverHead Service Entrance Conductors • Special locations • Emergency Systems
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Article 4.0 Flexible Cords and Cables 4.0.1.8 Uses Not Permitted. Flexible Cords (extension cords) and cables shall not be used for the following; (1) As a substitute for fixed wiring of a structure
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2.30.2.4 Clearances of Service Entrance Conductors (b) Vertical Clearance from Ground. Servicedrop conductors where not in excess of 600 volts, nominal, shall have the following minimum clearance from the final grade:
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(1) 3000 mm – at the electric service entrance to buildings, also at the lowest point of the drip loop of the building electric entrance, and above areas or sidewalks accessible only to pedestrians, measured from the final grade or other accessible surface only for service-drop cables supported on and cabled together with a ground bare messenger where voltage does not exceed 300 volts to ground. (2) 3600 mm – over residential property and driveways, and those commercial areas not subject to traffic where voltage does not exceed 300 volts to ground. (3) 4500 mm – for those areas listed in the 3600 mm classification where voltage exceeds 300 volts to ground (4) 5500 mm – over public streets, alleys, roads, parking areas subject to truck traffic, driveways on other than residential property.
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8.0.2.1 Overhead Communication Wires and Cables (a) On Poles and In-Span (4) Clearance. Supply Service-drops of 0 - 750 volts running above and parallel to communication service drops shall have a minimum separation of 300 mm at the point of and at their attachment to the building, provided the nongrounded conductors are insulated and that a clearance of not less than 1000 mm is maintained between two service at the pole.
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3.0.1.5 Underground Installation (a) Minimum Cover Requirements. Direct-buried cable or conduit or other raceways shall be installed to meet the minimum cover requirements of Table 3.0.1.5.
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Article 7.0 Emergency Systems 7.0.1.5 Capacity. (a) Capacity and Rating. An emergency system shall have adequate capacity and rating for all loads to be operated simultaneously. The emergency system equipment shall be suitable for the maximum available fault current at its terminals
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Article 7.0 Emergency Systems 7.0.3 Sources of Power 7.0.3.1 General Requirements. Current supply shall be such that, in the event of failure of the normal supply to, or within the building or group of buildings concerned, emergency lighting, emergency power or both shall be available within the time required for the application but not to exceed 10 seconds. (a) Storage Battery. Storage batteries used as a source of power for emergency systems shall be of suitable rating and capacity to supply and maintain the total load for a minimum period of 1 ½ hours, without the voltage applied to the load falling 87 ½ percent of normal (b) Generator Set. (2) Internal Combustion as Prime Movers. Where internal combustion engines are used as the prime mover, an on-site fuel supply shall be provided with an on-site premise fuel supply sufficient for not less than 2 hours full demand operation of the system
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Article 5.0 Hazardous Locations (a) (b)
Classification of Locations Class 1 Locations. (1) Class 1, Division 1 – is a location in which ignitible concentrations of flammable gases or vapors can exist under normal operating conditions (2) Class 2, Division 2 – is a location in which volatile flammable liquids or flammable gases are handled, processed or used. (c) Class 2 Locations. (1) Class 2, Division 1 – is a location in which combustible dust is in the air under normal operating conditions in quantities sufficient to produce explosive or ingitible mixtures (2) Class 2, Division 2 – is a location in which combustible dust due to abnormal operation may be present in the air in quantities sufficient to produce explosive or ingitible mixtures. (d) Class 3 Locations (1) Class 3, Division 1 – is a location in which easily ignitible fibers or materials producing combustible flyings are handled, manufactured or used. (2) Class 3, Division 2 – is a location in which easilty ignitible fibers are stored or handled other than in the process of manufacture
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