Subpart K Electrical 29 CFR 1926.400 Vincent J. Giblin, General President Phone: (304) 253-8674 Fax: (304) 253-7758 E-mail: hazmat@iuoeiettc.org 1293 Airport Road Beaver, WV 25813 Operating Engineers National Hazmat Program

This material was produced under grant number 46C5-HT16 from the Occupational Safety and Health Administration, U.S. Department of Labor. It does not necessarily reflect the views or policies of the U.S. Department of Labor, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.

Operating Engineers National Hazmat Program Introduction Electricity is the flow of electrons through a conductor. Operating Engineers National Hazmat Program Operating Engineers National Hazmat Program

Operating Engineers National Hazmat Program Introduction This flow is called a current. Any material that allows electrons to flow through it is a conductor. A good good example would be copper wire, allowing electricity to flow much like water through a hose. Operating Engineers National Hazmat Program Operating Engineers National Hazmat Program

Operating Engineers National Hazmat Program Introduction This conductor must be covered by an insulator made of materials that do not conduct electricity easily. Glass, rubber, plastic, and dry wood are insulators. Operating Engineers National Hazmat Program Operating Engineers National Hazmat Program

Operating Engineers National Hazmat Program Introduction This brings up the topic of resistance. Insulators have high resistance to the current flow because it takes the path of least resistance which would be the conductor inside the insulator. Operating Engineers National Hazmat Program Operating Engineers National Hazmat Program

Operating Engineers National Hazmat Program Introduction The human body can be used as a conductor, sending electrical currents through the body much like water through a sponge. Operating Engineers National Hazmat Program

Operating Engineers National Hazmat Program Introduction When you have had an electrical shock you may: A. Stop breathing B. Burn the skin C. Cook internal organs D. Have internal bleeding E. Stop the heart Operating Engineers National Hazmat Program

Operating Engineers National Hazmat Program Introduction This - of course - is to be avoided. What may cause this to happen? It could be a short circuit or a ground fault. A short circuit may happen when two hot wires or a hot wire and a neutral wire of a circuit contact each other. This causes the resistance to lower. Operating Engineers National Hazmat Program

Operating Engineers National Hazmat Program Introduction A ground fault may be caused by the hot conductor coming into contact with an outlet or tool casing. The tool may continue to run until something touches the outlet or the tool case, thus creating a multiple path to ground and casing shock. Operating Engineers National Hazmat Program

Operating Engineers National Hazmat Program Introduction By using this standard, you will become aware of the electrical safety requirements that must be applied for the practical safe- guarding of employees using temporary or permanent electrical installations at a construction job-site. Operating Engineers National Hazmat Program

Operating Engineers National Hazmat Program Introduction This standard was first issued in 1971. It has since been updated in 1991. The subpart K is divided into four major divisions: 1. 1926.402-408: Installation Safety Requirements 2. 1926.416 & .417: Safety-Related Work Practices Operating Engineers National Hazmat Program

Operating Engineers National Hazmat Program Introduction The subpart K is divided into four major divisions: 3. 1926.431 Safety-Related & .432: Maintenance & Environmental Considerations 4. 1926.441: Safety Requirements for Special Equipment Operating Engineers National Hazmat Program

Installation Safety Requirements 1926-403 General Requirements These general requirements would apply to all electrical conductors and equipment: 1. Approved 5. Suitable 2. Strong and durable 6. Insulated 3. Heat and arc effects 7. Classified location 4. Safeguarding Operating Engineers National Hazmat Program

Installation Safety Requirements 1926-403 General Requirements (a) Approval of all electrical conductors and equipment shall be approved. (b) Examination, installation, and use of equipment. The employer is to ensure that electrical equipment is free from recognized hazards that are likely to cause death or serious physical harm to employees. Operating Engineers National Hazmat Program

Installation Safety Requirements 1926-403 General Requirements (c) Interrupting rating: Equipment intended to break current shall have an interrupting rating at system voltage sufficient for current that must be interrupted. Operating Engineers National Hazmat Program

Installation Safety Requirements 1926-403 General Requirements (d) Mounting and cooling of equipment: Mounting-Electric equipment is to be firmly secured to the surface on which it is mounted. No wooden plugs are to be used. Cooling- Electrical equipment depending upon the natural circulation of air is to be installed so that the air floe is not hindered by any obstacles. Operating Engineers National Hazmat Program

Installation Safety Requirements 1926-403 General Requirements (e) Splices: Conductors are to be spliced or joined with splicing devices designed for the use or by brazing, welding, or soldering with a fusible metal or alloy. Splices, joints, and free ends are t be covered with proper insulation Operating Engineers National Hazmat Program

Installation Safety Requirements 1926-403 General Requirements (f) Arcing parts: Electrical equipment producing arcs, sparks, flame, or molten metal shall be enclosed or separated from all combustible material Operating Engineers National Hazmat Program

Installation Safety Requirements 1926-403 General Requirements (g) Marking: Electrical equipment is not to be used unless it is properly marked with the manufacturer’s name or if it does not provide voltage, current, wattage, or other ratings necessary. Operating Engineers National Hazmat Program

Installation Safety Requirements 1926-403 General Requirements (h) Identification of disconnecting means and circuits: Each disconnecting means shall be legibly marked to indicate its purpose. Each service, feeder, and branch circuit shall be legibly marked to indicate its purpose. Operating Engineers National Hazmat Program

Installation Safety Requirements 1926-403 General Requirements (i) 600 volts, nominal, or less Working Clearances are to follow Table K-1 Table K-1 Operating Engineers National Hazmat Program

Installation Safety Requirements 1926-403 General Requirements (i) 600 volts, nominal, or less Clear spaces are not to be used for storage. There should be at least one entrance for access to the working space about electric equipment The working space in front of service equipment that is exposed should not be less than 3 feet and the minimum headroom shall be 6’3”. Operating Engineers National Hazmat Program

Installation Safety Requirements 1926-403 General Requirements (i) 600 volts, nominal, or less Live parts of electric equipment are to be guarded against accidental contact. Partitions, screens, and placement on elevated levels of 8 feet or more above the work surface, are all means of guarding and are to be accessible only to qualified persons. Operating Engineers National Hazmat Program

Installation Safety Requirements 1926-403 General Requirements (j) Over 600 volts, nominal This electrical equipment shall be surrounded by a wall, screen, or fence, access to which is controlled by lock and key or under the observation of a qualified person at all times. Those installations that have exposed live parts are to be accessible to qualified persons only. Operating Engineers National Hazmat Program

Installation Safety Requirements 1926-403 General Requirements (j) Over 600 volts, nominal Sufficient space is needed to permit ready and safe operation and maintenance. The minimum clear workspace shall not be less than 6’6” high, or less than 3’ wide with adequate space to permit at lest a 90o opening or doors or panels. There should be at least one entrance to this work space not less than 24” wide and 6’6” high. Operating Engineers National Hazmat Program

Installation Safety Requirements 1926-403 General Requirements (j) Over 600 volts, nominal The minimum clear working space in front of electric equipment shall not be less than specified in Table K-2 Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection (a) Conductors used as either grounded or as an equipment grounding conductor are to be distinguishable from all other conductors. Grounded- Neutral color, current carrying conductor Grounding- Bare or green color dedicated to frames Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection The polarity connections shall not be changed by the use of grounded conductors. A grounding terminal or device on a receptacle, cord connector,or attachment plug shall not be used for purposes other than grounding. Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection (b) Branch circuits are used for ground-fault protection. Ground fault circuit interrupters or an assured equipment grounding conductor program are to be used to protect the employees on the construction site. repairs Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection (c) Outside conductors and lamps (i) Power Conductors on poles are to be separated from communication conductors as follows:  30 inches if below communication conductors Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection (c) Outside conductors and lamps (i) Power Conductors on poles are to be separated from communication conductors as follows:  24 inches if above communication and 300 volts or less  30 inches if above communication and more than 300 volts Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection (c) Outside conductors and lamps (ii) Clearance from ground: 10 ft - above sidewalks, grade, platform 12 ft - vehicular traffic 15 ft - other than public streets, alleys, roads, and driveways 18 ft - above public streets, alley, roads, and driveway Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection (c) Outside conductors and lamps (iii) Clearance from building openings is to be at least 3 feet (iv) Clearance over roofs 8 ft - insulated conductors 10 ft - covered conductors 15 ft - bare conductors 18 ft - if used for vehicles Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection (c) Outside conductors and lamps Outdoor lamps are to be located below all live conductors, or electric equipment unless other specific safeguards are required for relamping. Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection (d) Services Means will be provided to disconnect all conductors in a building or other structure from the service-entrance conductors, indicating whether it is in the open or closed position. They shall be installed at a readily accessible location nearest the point of entrance of the service-entrance conductors. Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection (e) Overcurrent protection- (1)600 volts or less Protection of conductors and equipment from overcurrent of circuits can be done by making certain: (i) Conductors have sufficient ampacity for job ( ii) No interruptions from overcurrent devices Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection (e) Overcurrent protection-(1) 600 volts or less (iii) All cartridge fuses are provided with disconnecting means. (iv) Overcurrent devices are readily accessible (v) Fuses, circuit breakers, and moving parts are shielded to protect employees (vi) Circuit breakers are clearly ON of OFF Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection (e) Overcurrent protection- (2) 600 volts or more Feeders and branch circuits over 600 volts, nominal, shall have short-circuit protection. Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection (f) Grounding Grounding keeps you from becoming part of the circuit by providing a separate low resistance pathway for electricity when it does not follow normal flow from hot to neutral. OSHA lists extensive requirements for grounding in (f)(1) through(11), focusing on things that give a continuous grounding path. Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection (f) Grounding In order to assure proper grounding, the path must:  Be permanent and continuous  Be of ample capacity  Have low resistance  Bond all circuit parts together Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection (f)(7) Equipment connected by cord and plug that must be grounded. 1. Handheld motor-operated tools 2. Equipment used in damp or wet locations or by employees standing on the ground or on metal floors or working inside of metal tanks or boilers 3. Portable and mobile X-ray equipment 4. Tools used in wet and/or conductive locations Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection (f)(11) Grounding of systems and circuits of 1000 volts and over 1. Portable and mobile high voltage equipment shall be supplied from a system having its neutral grounded through an impedance. 2. Provided ground-fault protection is to automatically de-energize any high voltage system component which has developed a ground fault. Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection (f)(11) Grounding of systems and circuits of 1000 volts and over 3. The grounding electrode to which the portable or mobile equipment system neutral impedance is connected shall be isolated from and separated in the ground by at least 20 feet from any other system or equipment grounding electrode Operating Engineers National Hazmat Program

1926.404 Wiring Design and Protection (f) Grounding Systems to be grounded 3 wire DC systems 2 wire DC systems AC circuit less than 50 volts AC circuits 50 volts to 1000 volts Exempted if less than 50 volts and isolation transformer and also if double insulated. Operating Engineers National Hazmat Program

1926.405 Wiring Methods, Components, and Equipment We will touch briefly on each of the elements of this section. (a)In discussing the general requirements of wiring methods, metal raceways, cable armor, and other metal enclosures for conductors shall be metallically joined together into a continuous electric conductor. Operating Engineers National Hazmat Program

1926.405 Wiring Methods, Components, and Equipment Temporary power and wiring methods shall be removed immediately upon completion of construction or the purpose for which the wiring was installed. The general requirements for temporary wiring are listed in (a)(2)(ii)(A-J). Operating Engineers National Hazmat Program

1926.405 Wiring Methods, Components, and Equipment Covering lights in this section ,(F-G), temporary lights shall not be suspended by their electric cords unless cords and lights are designed for this means of suspension. Operating Engineers National Hazmat Program

1926.405 Wiring Methods, Components, and Equipment Portable electric lighting used in wet and/or other conductive locations, such as drums, tanks, and vessels, shall be operated at 12 volts or less. 120-volt lights may be used if protected by a ground-fault circuit interrupter. Operating Engineers National Hazmat Program

1926.405 Wiring Methods, Components, and Equipment Covering, also,the commonly used flexible extension cords and cables, section (I). They are to be protected from damage as they may pass through doorways or other pinch joints. Sharp corners and projections shall be avoided. Never pass extension cords through walls, floors, ceilings, windows, or doors. Operating Engineers National Hazmat Program

1926.405 Wiring Methods, Components, and Equipment (J) explains extension cords shall be of three-wire type and designed for hard or extra-hard usage, as in those used by portable lights. Never use a cord without a ground, the odds increase that a fault current will flow through you. Operating Engineers National Hazmat Program

1926.405 Wiring Methods, Components, and Equipment (b)Conductors entering boxes, cabinets, or fittings are to be protected from abrasion. Openings through which conductors enter and those not in use shall be effectively closed. These boxes and fittings shall be provided with the appropriate covers. Operating Engineers National Hazmat Program

1926.405 Wiring Methods, Components, and Equipment (c) Knife switches: Single-throw knife switches shall be so connected that the blades are dead when the switch is in the open position. They are to be placed so that gravity will not tend to close them and have a locking device that ensures the blades remain in the open position when set. Operating Engineers National Hazmat Program

1926.405 Wiring Methods, Components, and Equipment (c) Knife switches: Double-throw knife switches may be mounted so that the throw will be either vertical or horizontal. A locking device shall be provided to ensure the blades remain in the open position when so set. Operating Engineers National Hazmat Program

1926.405 Wiring Methods, Components, and Equipment (d) Switchboards and panelboards. Switchboards with exposed live parts are to be located in permanently dry locations and accessible only to qualified persons. They should be mounted appropriately and have dead fronts. Operating Engineers National Hazmat Program

1926.405 Wiring Methods, Components, and Equipment (e) Proper Enclosures for damp or wet locations are to prevent moisture or water from entering and accumulating within the enclosures. For this reason, switches and circuit breakers are to be placed in weatherproof enclosures. (f) All conductors used for general wiring shall be insulated unless otherwise permitted in this Subpart. Operating Engineers National Hazmat Program

1926.405 Wiring Methods, Components, and Equipment (g) Flexible cords and cables are to used only for: A. Pendants B. Fixture wiring C. Portable appliances D. Elevator cables E. Crane/Hoist wiring F. Connection of stationary equipment G. Noise/Vibration prevention H. Removable connections for maintenance Operating Engineers National Hazmat Program

1926.405 Wiring Methods, Components, and Equipment (h) Portable cables over 600 volts shall consist of No. 8 or larger conductors employingflexible stranding. Cables operated at over 2000 volts are to be shielded in order to confine the voltage stresses to the insulation. (i) Fixture wires are to be suitable for the voltage, temperature, and location of use. Operating Engineers National Hazmat Program

1926.405 Wiring Methods, Components, and Equipment (j) Requirements are covered fore general equipment use inclusive of: 1. Lighting fixtures, lampholders, lamps and receptacles 2. Receptacles, cord connectors, and attachment plugs 3. Appliances 5. Transformers 4. Motors 6. Capacitors Operating Engineers National Hazmat Program

1926.406 Specific purpose equipment and installations (a) Cranes and hoists (b) Elevators, escalators, walks (c) Electric welders-disconnecting means (d) X-ray equipment Operating Engineers National Hazmat Program

Operating Engineers National Hazmat Program 1926.407 Hazardous Locations This section covers requirements for electric equipment and wiring in locations which are classified depending on the properties of the flammable vapors, liquids or gases, or combustible dusts or fibers which may be present. Operating Engineers National Hazmat Program

Operating Engineers National Hazmat Program 1926.407 Hazardous Locations These hazardous locations are assigned six designations as follows: Class I - Division1 and 2 - Gasses & Vapors Class II - Division 1 and 2 - Dusts Class III - Division 1 and 2 - Fibers Operating Engineers National Hazmat Program

Operating Engineers National Hazmat Program 1926.407 Hazardous Locations Electrical installations of equipment in hazardous locations shall be approved as intrinsically safe (permitted in any hazardous location included in its listing or labeling) or approved for the hazardous location (class of location and ignitable or combustible properties of any specific element present). Operating Engineers National Hazmat Program

Operating Engineers National Hazmat Program 1926.408 Special systems (a) Systems over 600 volts (b) Class 1, Class 2, Class 3 remote control, signaling, and power-limited circuits (c) Communication systems Operating Engineers National Hazmat Program

1926.416 Safety-Related Work Practices (a) Protection of employees (b) Passageways and open spaces (c) Load ratings (d) Fuses (e) Cords and cables (f) Interlocks (g) Use of equipment Operating Engineers National Hazmat Program

1926.417 Lockout and tagging of circuits (a) Controls (b) Equipment and circuits (c) Tags (d) Lockout and tagging Operating Engineers National Hazmat Program

1926.431 Maintenance of equipment The employer shall ensure that all wiring components and utilization equipment in hazardous locations are maintained in a dust-tight, dust-ignition-proof, or explosion-proof condition, as appropriate. Operating Engineers National Hazmat Program

1926.432 Environmental deterioration of equipment (a) Deteriorating agents 1. Damp or wet locations 2. Exposure to gases, fumes, vapors, liquids, or other agents having a deteriorating effect on the conductors or equipment 3. Exposure to excessive temperatures. Operating Engineers National Hazmat Program

1926.432 Environmental deterioration of equipment (b) Protection against corrosion. Metal raceways, cable armor, boxes, cable sheathing, cabinets, elbows, couplings, fittings, supports, and support hardware shall be of materials appropriate for the environment in which they are to be installed. Operating Engineers National Hazmat Program

1926.441 Batteries and battery charging (1) Unsealed batteries are to be located in well ventilated areas to (2)ensure diffusion of the gases and prevent the accumulation of and explosive mixture. (3)Substantial racks and trays are to be supplied and treated to make them resistant to the electrolyte. (4) Floors are to be acid resistant and (5) workers who handle acids or batteries are to be provided with face shields, aprons,and rubber gloves. Operating Engineers National Hazmat Program

1926.441 Batteries and battery charging (6) Facilities for quick drenching of the eyes and body shall be provided within 25 feet of battery handling areas. (7) Facilities shall be provided for flushing and neutralizing spilled electrolyte and for fire protection. Operating Engineers National Hazmat Program

This material was produced under grant number 46C5-HT16 from the Occupational Safety and Health Administration, U.S. Department of Labor. It does not necessarily reflect the views or policies of the U.S. Department of Labor, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.

Operating Engineers National Hazmat Program End This publication was made possible by grant numbers 5 U45 ES06182-13 AND 5 U45 ES09763-13 from the National Institute of Environmental Health Sciences (NIEHS), NIH. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIEHS, NIH. Operating Engineers National Hazmat Program