4.6: Safeguards

Ensure Overhead Power Line Safety

Overhead power lines must be deenergized and grounded by the owner or operator of the lines, or other protective measures must be provided before work is started such as PPE (rubber insulating gloves, hoods, sleeves, matting, blankets, line hose, and industrial protective helmets.) Protective measures (such as guarding or insulating the lines) must be designed to prevent contact with the lines. Employers should train workers regarding power line hazards and about the available protective measures. Workers need to be fully informed about what jobs may have electrical hazards, and the measure(s) they will take to control the hazards. Also, workers should be reminded that they should always ask questions if they have any doubts about maintaining safe working conditions.

Isolate Electrical Parts

Electrical parts, conductors entering boxes, cabinets, or fittings shall be protected from abrasion, and openings through which conductors enter and shall be effectively closed. Unused openings in cabinets, boxes, and fittings shall also be effectively closed. All pull boxes, junction boxes, and fittings shall be provided with covers. Metal covers shall be grounded. In energized installations each outlet box shall have a cover, faceplate, or fixture canopy. Covers of outlet boxes having holes through which flexible cord pendants pass shall be provided with bushings designed for the purpose or shall have smooth, well-rounded surfaces on which the cords may bear.

Lockout/Tagout

Lockout device: A device that utilizes a positive means such as a lock, either key or combination type, to hold an energy-isolating device in the safe position and prevent the energizing of a machine or equipment. Included are blank flanges and bolted slip blinds.

Tagout device: A prominent warning device, such as a tag and a means of attachment, which can be securely fastened to an energy-isolating device in accordance with an established procedure, to indicate that the energy-isolating device and the equipment being controlled may not be operated until the tagout device is removed.

Tagout devices shall warn against hazardous conditions if the machine or equipment is energized and shall include a legend such as the following: Do Not Start. Do Not Open. Do Not Close. Do Not Energize. Do Not Operate.

Locks, tags, chains, wedges, key blocks, adapter pins, self-locking fasteners, or other hardware shall be provided by the employer for isolating, securing or blocking of machines or equipment from energy sources.

Supply GFCI

OSHA ground-fault protection rules and regulations have been determined necessary and appropriate for worker safety and health. Therefore, it is the employer's responsibility to provide either: (a) ground-fault circuit interrupters on construction sites for receptacle outlets in use and not part of the permanent wiring of the building or structure; or (b) a scheduled and recorded assured equipment grounding conductor program on construction sites, covering all cord sets, receptacles which are not part of the permanent wiring of the building or structure, and equipment connected by cord and plug which are available for use or used by workers. Receptacles at the ends of extension cords must be protected by GFCIs. Also, there are GFCI circuit breakers. These protected circuit breakers are installed on the main circuit board. It protects an entire circuit.

Establish and implement an assured equipment grounding conductor program

The assured equipment grounding conductor program covers all cord sets, receptacles which are not a part of the permanent wiring of the building or structure, and equipment connected by cord and plug which are available for use or used by employees. OSHA requires that a written description of the employer's assured equipment grounding conductor program, including the specific procedures adopted, be kept at the jobsite. This program should outline the employer's specific procedures for the required equipment inspections, tests, and test schedule.

The required tests must be recorded, and the record maintained until replaced by a more current record. The written program description and the recorded tests must be made available, at the jobsite, to OSHA and to any affected employee upon request. The employer is required to designate one or more competent persons to implement the program. Electrical equipment noted in the assured equipment grounding conductor program must be visually inspected for damage or defects before each day's use. Any damaged or defective equipment must not be used by the employee until repaired.

Two tests are required by OSHA. One is a continuity test to ensure that the equipment grounding conductor is electrically continuous. It must be performed on all cord sets, receptacles which are not part of the permanent wiring of the building or structure, and on cord- and plug-connected equipment which is required to be grounded. This test may be performed using a simple continuity tester, such as a lamp and battery, a bell and battery, an ohmmeter, or a receptacle tester.

Ensure power tools are maintained in safe condition

The employer needs to ensure that all power tools and equipment are maintained in a safe condition to: (1) Ground power supply systems, electrical circuits, and electrical equipment (2) Frequently inspect electrical systems to ensure path to ground is continuous (3) Ensure workers understand how to inspect electrical equipment prior to use (4) Ensure ground prongs are not removed from tools or extension cords (5) Ground exposed metal parts of equipment.

Ensure proper guarding

Guarding involves locating or enclosing electrical equipment to ensure workers do not accidentally come into contact with its live parts. Effective guarding requires equipment with exposed parts operating at 50 volts or more to be placed where they are accessible only to authorized people qualified to work with/on the equipment. Recommended locations are a room, vault, or similar enclosure; a balcony, gallery, or elevated platform; or a site elevated 8 feet or more above the floor. Sturdy, permanent screens can also serve as effective guards

Provide training

Workers need to be trained in and familiar with the safety-related work practices that pertain to their respective job assignments. Train workers working with electric equipment in safe work practices to: (1) Deenergize electric equipment before inspecting or repairing (2) Use cords, cables, and electric tools that are in good repair (3) Lockout / Tagout recognition and procedures (4) Use appropriate protective equipment.

Ensure proper use of flexible cords

These ratings are derived from the National Electrical Code, and are required to be indelibly marked approximately every foot along the length of the cord. Examples of these codes are: S, ST, SO, and STO for hard service, and SJ, SJO, SJT, and SJTO for junior hard service. Extension cords must be 3-wire type so they may be grounded, and to permit grounding of any tools or equipment connected to them. Limit exposure of connectors and tools to excessive moisture by using watertight or sealable connectors.