Concrete, brick, and tile walls are considered as grounded surfaces.ģWorking space is not required in back of equipment such as dead-front switchboards or control assemblies that has no renewable or adjustable parts (such as fuses or switches) on the back and where all connections are accessible from locations other than the back. Table S-2-Minimum Depth of Clear Working Space at Electric Equipment, Over 600 V Nominal voltage to groundġMinimum depth of clear working space in front of electric equipment with a nominal voltage to ground above 25,000 volts may be the same as that for 25,000 volts under Conditions A, B, and C for installations built before April 16, 1981.Ĭondition B - Exposed live parts on one side and grounded parts on the other side. Where rear access is required to work on deenergized parts on the back of enclosed equipment, a minimum working space of 762 mm (30 in.) horizontally shall be provided. Working space is not required in back of assemblies such as dead-front switchboards or motor control centers where there are no renewable or adjustable parts (such as fuses or switches) on the back and where all connections are accessible from locations other than the back. Insulated wire or insulated busbars operating at not over 300 volts are not considered live parts.Ĭondition B - Exposed live parts on one side and grounded parts on the other side.Ĭondition C - Exposed live parts on both sides of the work space (not guarded as provided in Condition A) with the operator between.ģ. Conditions A, B, and C are as follows:Ĭondition A - Exposed live parts on one side and no live or grounded parts on the other side of the working space, or exposed live parts on both sides effectively guarded by suitable wood or other insulating material. Minimum clear distances may be 0.7 m (2.5 ft) for installations built before April 16, 1981.Ģ. Table S-1-Minimum Depth of Clear Working Space at Electric Equipment, 600 V or Less Nominal voltage to groundġ.
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