Does "Subpart K - Electrical" Apply to You?

Subpart K provides the electrical standards for construction work. It includes an introduction to the subpart which explains that the subpart is divided into four major divisions:

  • Installation safety requirements
  • Safety-related work practices
  • Safety-related maintenance and environmental considerations
  • Safety requirements for special equipment (batteries and battery charging)

It also provides the definitions applicable to this subpart including:

Bonding - The permanent joining of metallic parts to form an electrically conductive path which will assure electrical continuity and the capacity to conduct safely any current likely to be imposed.

Grounded - Connected to earth or to some conducting body that serves in place of the earth.

Ground-fault circuit interrupter - A device for the protection of personnel that functions to deenergize a circuit or portion thereof within an established period of time when a current to ground exceeds some predetermined value that is less than that required to operate the overcurrent protective device of the supply circuit.

Qualified person - One familiar with the construction and operation of the equipment and the hazards involved.

To identify which electrical standards apply to you, click on the applicable tabs below.

Subpart K - Electrical

Do employees work on electrical equipment or installations used to provide electric power and light at the jobsite?

Do employees work on electrical equipment or installations used to provide electric power and light at the jobsite?

If yes, then the following standards will apply to you. These standards are applicable to installations, both temporary and permanent, used on the jobsite; but they do not apply to existing permanent installations that were in place before the construction activity commenced. They also cover portable and vehicle-mounted generators used to provide power for equipment used at the jobsite. They do not apply to installations used for the generation, transmission, and distribution of electric energy, including related communication, metering, control, and transformation installations as they are covered under subpart V, electric power transmission and distribution.

General requirements provides the standards for examination, installation and use of equipment, interrupting rating, mounting and cooling of equipment, slices, arcing parts, marking, and identification of disconnecting means and circuits. It includes requirements for guarding of live parts, headroom, working space and clearances around equipment operating at 600 volts or less.  It also provides requirements for conductors and equipment used on circuits exceeding 600 volts to include workspace around equipment, working space,  exposed live parts, lighting, and entrance and access to work space. 

Wiring design and protection provides standards for the use and identification of grounded and grounding conductors; branch circuits (i.e., ground-fault protection, outlet devices); outside conductors and lamps (i.e., 600 volts, nominal or less, location); services (i.e., disconnecting means, services over 600 volts); overcurrent protection (i.e., 600 volts, nominal or less, over 600 volts, nominal); and grounding (i.e., systems to be grounded, separately derived systems, portable and vehicle-mounted generators, conductors to be grounded, grounding connections, grounding path, supports and equipment to be grounded, methods of grounding, bonding). 

Wiring methods, components, and equipment for general use provides the standards on wiring methods (i.e., general requirements, temporary wiring); cabinets, boxes and fittings; knife switches; switchboards and panelboards; enclosures for damp and wet locations; cabinets, fittings and boxes; conductors for general wiring; flexible cords and cables (i.e., use, attachment plugs, splices, identification, strain relief, marking, passing through holes); fixture wires; portable cables over 600 volts; and equipment for general use (i.e., lighting fixtures, portable lamps, lamp holders, appliances, protection of live parts, transformers, capacitors). 

In addition, the standard on lockout and tagging of circuits provides for the tagging of controls, equipment and circuits that are to be deenergized or energized during the course of work. 

Some definitions applicable to this subpart include:

Damp location - Partially protected locations under canopies, marquees, roofed open porches, and like locations, and interior locations subject to moderate degrees of moisture, such as some basements.

Appliances - Utilization equipment, generally other than industrial, normally built in standardized sizes or types, which is installed or connected as a unit to perform one or more functions.

Wet location - Installations underground or in concrete slabs or masonry in direct contact with the earth, and locations subject to saturation with water or other liquids, such as locations exposed to weather and unprotected.

Additional related information can be found on the A-Z safety and health topic pages for electrical safetylockout/tagout and personal protective equipment.

Do you have specific purpose equipment (i.e., cranes, hoists, elevators, electric welders, x-ray equipment)?

Do you have specific purpose equipment (i.e., cranes, hoists, elevators, electric welders, x-ray equipment)?

If yes, then you need to comply with the standard on specific purpose equipment and installations as it provides electrical requirements for equipment and wiring used in connection with cranes, monorail hoists, hoists, and all runways; disconnecting means and control panels for elevators, escalators, and moving walks; disconnecting means for electric welders; and disconnecting means for x-ray equipment. 

Paragraph (a) - cranes and hoists. This paragraph applies to the installation of electric equipment and wiring used in connection with cranes, monorail hoists, hoists, and all runways. It provides requirements pertaining to disconnecting means, control, clearance, and grounding.

Paragraph (b) - elevators, escalators and moving walks. This paragraph provides the requirements pertaining to disconnecting means, and control panels. 

Paragraph (c) - electric welders. This paragraph provides the requirements pertaining to the disconnecting means for motor-generator, AC transformer, and DC rectifier arc welders, and resistance welders.

Paragraph (d) - x-ray equipment. This paragraph provides the requirements pertaining to disconnecting means and control of radiographic and fluoroscopic-type equipment.

In addition, the standard on lockout and tagging of circuits provides for the tagging of controls, equipment and circuits that are to be deenergized or energized during the course of work. 

Disconnecting means -  A device, or group of devices, or other means by which the conductors of a circuit can be disconnected from their source of supply.

Additional related information can be found on the A-Z safety and health topic pages for electrical safetylockout/tagoutradiation, ionizing and non-ionizing and personal protective equipment.

Do you have hazardous (i.e., flammable, combustible) locations?

Do you have hazardous (i.e., flammable, combustible) locations?

If yes, then you need to comply with the standard on hazardous (classified) locations which provides the 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 therein and the likelihood that a flammable or combustible concentration or quantity is present. This standard provides the requirements pertaining to electrical installations such as being intrinsically safe, approved for the location, safe for the location and having threaded conduits wrench tight.

Intrinsically safe equipment and associated wiring - Equipment and associated wiring in which any spark or thermal effect, produced either normally or in specified fault conditions, is incapable, under certain prescribed test conditions, of causing ignition of a mixture of flammable or combustible material in air in its most easily ignitable concentration.

This standard also provides that each room, section or area is considered individually in determining its classification. Hazardous (classified) locations are assigned six designations as follows:

Class I, Division 1 Class I, Division 2 - Class I locations are those in which flammable gases or vapors are or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures.

Class II, Division 1 Class II, Division 2 - Class II locations are those that are hazardous because of the presence of combustible dust.

Class III, Division 1 Class III, Division 2 - Class III locations are those that are hazardous because of the presence of easily ignitable fibers or flyings but in which such fibers or flyings are not likely to be in suspension in the air in quantities sufficient to produce ignitable mixtures.

Reference definitions applicable to this subpart for more detailed information regarding the breakdown of the above classifications. Additional related information can be found on the A-Z safety and health topic pages for electrical safety,personal protective equipmentcombustible dust and flammable liquids.

 

 

Do you have circuits or equipment operating at over 600 volts?

Do you have circuits or equipment operating at over 600 volts?

If yes, then you need to comply with the standard on special systems as it provides requirements for all circuits and equipment operating at over 600 volts. This standard provides three distinct paragraphs as follows:

Paragraph (a) - General requirements. This paragraph provides requirements for all circuits and equipment operated at over 600 volts. This includes wiring methods for fixed installations (i.e., above ground installations, installations emerging from the ground), interrupting and isolating devices (i.e., circuit breakers, fused cutouts), mobile and portable equipment, and tunnel installations (installation and use of high-voltage power distribution and utilization equipment which is associated with tunnels and which is portable and/or mobile, such as substations, trailers, cars, mobile shovels, draglines, hoists, drills, dredges, compressors, pumps, conveyors, and underground excavators). 

Paragraph (b) - Class 1, Class 2, and Class 3 remote control, signaling, and power-limited circuits. This paragraph provides requirements pertaining to classification of remote control, signaling, and power-limited circuits (i.e., maximum voltage), and marking. 

Paragraph (c) - Communication systems. This paragraph provides requirements for communications systems such as central-station-connected and non-central-station-connected telephone circuits, radio receiving and transmitting equipment, outside wiring for fire and burglar alarm, and similar central station systems. These installations need not comply with general requirementswiring design and protection (except paragraph (c)(1)(ii) - clearance from ground), wiring methods, components, and equipment for general usespecific purpose equipment and installations, and special systems (paragraphs (a) and (b). These requirements pertain to protective devices, conductor location, equipment location, and grounding.  

Additional related information can be found on the A-Z safety and health topic pages for electrical safety and personal protective equipment.

Do employees use electricity at the worksite?

Do employees use electricity at the worksite?

This is most likely yes as most employees use electricity when at a job site. If so, then you need to comply with the standard on general requirements which provides for the protection of employees (i.e., deenergizing and grounding circuits, guarding live circuits with insulation, use of insulated protective gloves), passageways and open spaces (i.e., barriers, work areas kept clear), load ratings, fuses (i.e., special tools), and cables and cords (i.e., not worn or frayed, not fastened with staples, hung from nails, or suspended by wire).

You will also need to comply with lockout and tagging of circuits which provides for the tagging of controls, equipment and circuits that are to be deenergized or energized during the course of work. 

Additional related information can be found on the A-Z safety and health topic pages for electrical safety, lockout/tagout and personal protective equipment.

 

Do employees provide safety-related maintenance on equipment?

Do employees provide safety-related maintenance on equipment?

If yes, then you need to comply with the standard on maintenance of equipment. It provides 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 and that there shall be no loose or missing screws, gaskets, threaded connections, seals, or other impairments to a tight condition.

In addition, the standard on lockout and tagging of circuits provides for the tagging of controls, equipment and circuits that are to be deenergized or energized during the course of work. 

Hazardous (classified) locations are assigned six designations as follows:

Class I, Division 1 Class I, Division 2 - Class I locations are those in which flammable gases or vapors are or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures.

Class II, Division 1 Class II, Division 2 - Class II locations are those that are hazardous because of the presence of combustible dust.

Class III, Division 1 Class III, Division 2 - Class III locations are those that are hazardous because of the presence of easily ignitable fibers or flyings but in which such fibers or flyings are not likely to be in suspension in the air in quantities sufficient to produce ignitable mixtures.

Explosion-proof apparatus - Apparatus enclosed in a case that is capable of withstanding an explosion of a specified gas or vapor which may occur within it and of preventing the ignition of a specified gas or vapor surrounding the enclosure by sparks, flashes, or explosion of the gas or vapor within, and which operates at such an external temperature that it will not ignite a surrounding flammable atmosphere.

Note: Reference definitions applicable to this subpart for more detailed information regarding the breakdown of the above classifications. Additional related information can be found on the A-Z safety and health topic pages for electrical safety, lockout/tagoutcombustible dust and flammable liquids.

Do employees install conductors or equipment in areas where environmental deterioration may be an issue?

Do employees install conductors or equipment in areas where environmental deterioration may be an issue?

If yes, then you need to comply with the standard on environmental deterioration of equipment. This standard provides requirements pertaining to deteriorating agents (i.e., damp or wet location; exposure to excessive temperatures; exposure to gases, fumes, vapors, and liquids; equipment approved for dry locations), and protection against corrosion.

Definitions applicable to this subpart includes:

Damp location - Partially protected locations under canopies, marquees, roofed open porches, and like locations, and interior locations subject to moderate degrees of moisture, such as some basements.

Dry location -  A location not normally subject to dampness or wetness. A location classified as dry may be temporarily subject to dampness or wetness, as in the case of a building under construction.

Wet location - Installations underground or in concrete slabs or masonry in direct contact with the earth, and locations subject to saturation with water or other liquids, such as locations exposed to weather and unprotected.

Additional related information can be found on the A-Z safety and health topic pages for electrical safety and personal protective equipment.

Do you store batteries or have battery charging installations?

Do you store batteries or have battery charging installations?

If yes, then you need to comply with the standard on batteries and battery charging. It provides general requirements pertaining to location, ventilation, racks and trays, personal protective equipment, fire protection, quick drenching facilities, and battery charging areas (i.e., designated areas, damage protection, vent caps).

Additional related information can be found on the A-Z safety and health topic pages for personal protective equipmentmedical services and first aid and acids and bases.