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Subchapter 5. Electrical Safety Orders
Group 2. High-Voltage Electrical Safety Orders
Article 35. Workspace and Guarding (Formerly Article 84)
(a) The minimum depth of clear working space about electrical equipment, such as switchgear, motor controllers, etc., shall not be less than set forth in Table 2932 unless otherwise specified in these orders. Clearances shall be measured from the energized parts if parts are exposed or from the enclosure front or opening, if parts are enclosed.
Table 2932 - Minimum Depth of Clear Working Space at Electric Equipment, Over 600 Volts
MINIMUM CLEAR DISTANCE FOR CONDITIONS
Where the conditions are as follows:
Condition 1 Exposed energized parts on one side and no energized or grounded parts on the other side of the working space, or exposed energized parts on both sides effectively guarded by suitable wood or other insulating material. Insulated wire or insulated busbars operating at not over 300 volts are not considered energized parts. Non-shielded insulated conductors shall be considered as exposed energized parts.
Condition 2 Exposed energized parts on one side and grounded parts on the other side. Concrete, brick, plaster, or tile walls will be considered as grounded surfaces.
Condition 3 Exposed energized parts on both sides of the workspace (not guarded as provided in Condition 1) with the operator between.
1. Workspace will not be required behind enclosed equipment such as dead-front switchboards or control assemblies, provided there are no renewable or adjustable parts; such as fuses, switches, etc., on the back, and provided all connections are accessible from locationsother than the back. Where rear access is required to work on the deenergized parts on the back of enclosed equipment, a minimum working space of 30 inches (762 mm) horizontally shall be provided.
2. Minimum 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 1, 2 and 3 for installations built before April 16, 1981.
(b) Suitable space shall be provided and maintained about electrical equipment to permit ready and safe operation and maintenance of such equipment. Where energized parts are exposed, the minimum clear workspace shall not be less than 6 1/2 feet (1.98 m) high (measured vertically from the floor or platform), nor less than 3 feet (914 m) wide (measured parallel to the equipment). The depth shall be as required in subsection 2932(a). In all cases, the workspace shall be adequate to permit at least a 90-degree opening of doors or hinged panels.
(c) If switches, cutouts, or other equipment operating at 600 volts, nominal, or less, are installed in a room or enclosure where there are exposed energized parts or exposed wiring operating at over 600 volts, nominal, the high-voltage equipment shall be effectively separated from the space occupied by the low-voltage equipment by a suitable partition, fence, or screen. However, switches or other equipment operating at 600 volts, nominal, or less, and serving only equipment within the high-voltage vault, room, or enclosure may be installed in the high-voltage enclosure, room, or vault if accessible to qualified persons only.
(d) The following requirements apply to the entrances to all buildings, rooms, or enclosures containing exposed energized parts or exposed conductors operating at over 600 volts, nominal:
(1) The entrances shall be kept locked unless they are under the observation of a qualified person at all times; and
(2) Permanent and conspicuous warning signs shall be provided, reading substantially as follows:
”DANGER - HIGH VOLTAGE - KEEP OUT.”
(e) Pipes or ducts that are foreign to the electrical installation and that require periodic maintenance or whose malfunction would endanger the operation of the electrical system may not be located in the vicinity of service equipment, metal-enclosed power switchgear, or industrial control assemblies. Protection shall be provided where necessary to avoid damage from condensation leaks and breaks in such foreign systems.
Note to subsection 2932(e): Piping and other facilities are not considered foreign if provided for fire protection of the electrical installation.