Revision 12/06 Electrical Safety Program

Revision 12/06 General company policy

The purpose of this program is to inform interested persons, including employees, that our company is complying with the OSHA Electrical Safety Standard at §1910.333 by determining that this workplace needs written procedures for preventing electric shock or other injuries resulting from direct/indirect electrical contacts to employees working on or near energized or deenergized parts. This program applies to all work operations at ____________ where employees may be exposed to live parts and/or those parts that have been deenergized.

____________ has overall responsibility for coordinating safety and health programs in this company. 

____________ is the person having overall responsibility for the Electrical Safety Program. ____________ will review and update the program, as necessary.

Copies of the written program may be obtained from ____________ in ____________. Under this program, our employees receive instructions in the purpose and use of energy control procedures, as well as the other required elements of the Control of Hazardous Energy standard. This instruction includes the deenergizing of equipment, applying locks and tags, verifying deenergization, and equipment reenergizing.

We encourage all suggestions because we are committed to creating a safe workplace for all our employees and a successful electrical safety program is an important component of our overall safety plan. We strive for clear understanding, safe work practices, and involvement in the program from every level of the company.

Revision 12/06 Hazard analysis report

To determine areas of ____________ that need to be included in the Electrical Safety Program, ____________ has conducted a hazard analysis of our workplace. This analysis located in ____________, has provided us with information identifying which departments have equipment using electricity, various types of wiring installations, and the types of employee functions that must be covered by the Electrical Safety Program. The departments/areas of our company identified as having electrically operated equipment and/or wiring installations are ____________.

Electrically operated equipment that must be deenergized before work can be done on it and where it is located includes ____________.

Employees of our company who are qualified to work on, near, or with energized electric circuits and equipment are ____________.

Employees working on, near, or with energized electric circuits and equipment who have limited knowledge of electrical circuitry are ____________.

Revision 12/06 Training program

Every employee in our company who faces the risk of electric shock from working on or near energized or deenergized electrical sources receives training in electrical related safety work practices pertaining to the individual’s job assignment.

The goal of our electrical safety training program is to ensure that all employees understand the hazards associated with electric energy and that they are capable of performing the necessary steps to protect themselves and their co workers.

Our electrical training program covers these basic elements:

• Lockout and tagging of conductors and parts of electrical equipment.
• Safe procedures for deenergizing circuits and equipment.
• Application of locks and tags.
• Verification that the equipment has been deenergized.
• Procedures for reenergizing the circuits or equipment.
• Other electrically related information which is necessary for employee safety.

In our facility, all the persons working on or near energized or deenergized electric sources are considered “qualified” to work safely with electrical energy and have received the appropriate training and certification to do so. In addition to the basic training elements, our “qualified” employees are trained in the skills and techniques necessary to identify exposed live parts, determine nominal voltages, and clearance distances and corresponding voltages. This group of employees has also received additional training that includes ____________.

The format we follow for our training program is ____________.

The procedures we follow when training new employees who will be working on or near electrical equipment or circuitry are ____________. When changes involving electrical elements occur in our company, we provide additional employee training to ensure the safety of all affected workers. In this case, we follow these procedures: ____________.

____________ conducts the electrical safety training for all employees. Every employee who participates in the Electrical Safety Program receives a certificate which they sign verifying that they have completed the course, that they understand the information presented, and that they will follow all company policies and procedures regarding electrical safety. These signed certificates of training as well as all training materials and documentation are kept by ____________.

Revision 12/06 Lockout/tagout program

It is our company’s policy that circuits and equipment must be disconnected from all electric energy sources before work on them begins. We use lockout and tagging devices to prevent the accidental reenergization of this equipment. These lockout and tagging procedures are the main component of our electrical safety program. The safety procedures that make up our lockout and tagging program include these elements:

• Deenergizing circuits and equipment. We disconnect the circuits and equipment to be worked on from all electric energy sources and we release stored energy that could accidentally reenergize equipment.
• Application of locks and tags. Only authorized employees are allowed to place a lock and tag on each disconnecting means used to deenergize our circuits or equipment before work begins. Our locks prevent unauthorized persons from reenergizing the equipment or circuits and the tags prohibit unauthorized operation of the disconnecting device.

• Verification of deenergized condition of circuits and equipment. Prior to work on the equipment, we require that a “qualified” employee verifiy that the equipment is deenergized and cannot be restarted.
• Verification of deenergized condition of circuits and equipment. Reenergizing circuits and equipment. Before circuits or equipment are reenergized, we follow these steps in this order:
  • A “qualified” employee conducts tests and verifies that all tools and devices have been removed.
  • All exposed employees are warned to stay clear of circuits and equipment.
  • Authorized employees remove their own locks and tags.
  • We do a visual inspection of the area to be sure all employees are clear of the circuits and equipment.

In addition to these lockout/tagout elements, we ____________.

____________ are the employees trained and authorized to deenergize, verify, and reenergize electric circuits and equipment in our company.

Revision 12/06 Enforcement

Constant awareness of and respect for electrical hazards, and compliance with all safety rules are considered conditions of employment. Supervisors and individuals in the Safety and Personnel Department reserve the right to issue disciplinary warnings to employees, up to and including termination, for failure to follow the guidelines of this program.

Revision 12/06 Appendix

We have attached to this plan any lists, samples, or procedures we thought would ensure better understanding of our written program.

Electrical Safety-Related Work Practices: Excerpts from OSHA Instruction STD 1-16.7

The following excerpts are from an instructional document that was issued by OSHA to its inspectors. The document establishes policies and provides guidelines to ensure uniform enforcement of §1910.331 through §1910.335, the Electrical Safety-Related Work Practices standard. You, the employer, can use this document to determine how OSHA expects the electrical standard to be implemented in the workplace.

Inspection guidelines

In so far as possible, the compliance officer shall integrate inspection procedures for this standard with those of §1910.147 (lockout/tagout standard). The following guidance provides a general framework to assist the compliance officer during all inspections:

1. The employer’s written procedures required under §1910.333(b)(2)(i) shall be reviewed to determine if they cover the hazards likely to be encountered.
   1. A copy of paragraph (b) of §1910.333 maintained by the employer will fulfill this requirement.
   2. A copy of the written procedures for locking and tagging required by §1910.147 will also comply with this requirement, provided those procedures address the electrical safety hazards covered by Subpart S and provided the procedures conform to §1910.333(b).
   3. If the employer has chosen to utilize procedures developed to comply with 1910.147 for electrical as well as other hazards, the written procedures must include steps corresponding to requirements in §1910.333 for application of locks and tags and verification of deenergized conditions (§1910.333(b)(2)(iii)(D) and (b)(2)(iv)(B)).

2. Beginning August 6, 1991, the training practices of the employer for qualified and unqualified employees shall be evaluated to assess whether the training provided is appropriate to the tasks being performed or to be performed.
   1. All employees who face a risk of electric shock, burns or other related injuries, not reduced to a safe level by the installation safety requirements of Subpart S, must be trained in safety-related work practices required by §1910.331-.335.
   2. In addition to being trained in and familiar with safety related work practices, unqualified employees must be trained in the inherent hazards of electricity, such as high voltages, electric current, arcing, grounding, and lack of guarding. Any electrically related safety practices not specifically addressed by §§1910.331 through 1910.335 but necessary for safety in specific workplace conditions shall be included.
   3. The training of qualified employees must include at the minimum the following:
      1. The ability to distinguish exposed live parts from other parts of electric equipment.
      2. The ability to determine the nominal voltage of live parts.
      3. The knowledge of clearance and/or approach distances specified in §1910.333(c).
   4. During walkaround inspections, compliance officers shall evaluate any electrical-related work being performed to ascertain conformance with the employer’s written procedures as required by §1910.333(b)(2)(i) and all safety-related work practices in §§1910.333 through 1910.335. (See J. of this instruction for clarification.)
   5. Any violations found must be documented adequately, including the actual voltage level.
      
      

Interpretative guidance

The following guidance is provided relative to specific provisions of the standard for Electrical Safety-Related Work Practices:

1. Definitions: Qualified/Unqualified persons
   1. The standard defines a qualified person as one familiar with the construction and operation of the equipment and the hazards involved. “Qualified Persons” are intended to be only those who are well acquainted with and thoroughly conversant in the electric equipment and electrical hazards involved with the work being performed.
      1. Whether an employee is considered to be a “qualified person” will depend on various circumstances in the workplace. It is possible and, in fact, likely for an individual to be considered “qualified” with regard to certain equipment in the workplace, but “unqualified” as to other equipment. (See §1910.332(b)(3) for training requirements that specifically apply to qualified persons.) Only qualified persons may place and remove locks and tags.
      2. An employee who is undergoing on-the-job training, who, in the course of such training, has demonstrated an ability to perform duties safely at his or her level of training, and who is under the direct supervision of a qualified person, is considered to be a qualified person for the performance of those duties.
   2. Where the term “may not” is used in these standards, the term bears the same meaning as “shall not”.
   3. Training requirements apply to all employees in occupations that carry a risk of injury due to electrical hazards that are not sufficiently controlled under §§1910.303 through 1910.308.

2. Scope/Coverage
   1. The provisions of the standard cover all employees working on, near or with premises wiring; wiring for connection to supply; other wiring such as outside conductors on the premises; and optical fiber cable where the fiber cable installations are made along with electric conductors and the optical fiber cable types are those that contain noncurrent-carrying conductive members such as metallic strength members and metallic vapor barriers.
   2. The standard does not cover qualified workers (but does cover unqualified workers) performing work on the following:
      1. Electric power generation, transmission, and distribution installations located in buildings used for such purposes or located outdoors.
         NOTE:   Work on the specified electrical installations is excluded, but work on other electric equipment in the buildings is not excluded.
      2. Communications installations covered under §1910.268.
      3. Installations in ships, watercraft, railway rolling stock, aircraft, or automotive vehicles other than mobile homes and recreational vehicles.
      4. Installations of railways for generation, transformation, transmission, or distribution of electrical power used exclusively for rolling stock or installations of railways used exclusively for signaling and communication purposes.
   3. The standard for Electrical Safety-Related Work Practices was developed to complement the existing electrical standards. The new standard includes requirements for work performed on or near exposed energized and deenergized parts of electric equipment, use of electrical protective equipment, and the safe use of electrical equipment.
   4. Exposure to unexpected electrical energy release that could result in electric shock or burns or in an explosion caused by an electric arc is covered by the standard for Electrical Safety-Related Work Practices. Safeguarding workers from other hazards related to the unexpected release of hazardous energy during servicing and maintenance operations is covered by §1910.147, the lockout/tagout standard.
      1. Section 1910.333(a)(1) requires that live parts be deenergized before a potentially exposed employee works on or near them. OSHA believes that this is the preferred method for protecting employees from electrical hazards. The employer is permitted to allow employees to work on or near exposed live parts only:
         1. If the employer can demonstrate that deenergizing introduces additional or increased hazards, or
         2. If the employer can demonstrate that deenergizing is infeasible due to equipment design or operational limitations.
      2. Under §1910.333(a)(2) if the employer does not deenergize (under the conditions permitted in §1910.333(a)(1)), then suitable safe work practices for the conditions under which the work is to be performed shall be included in the written procedures and strictly enforced. These work practices are given in §§1910.333(c) and 1910.335.
      3. Only qualified persons shall be allowed to work on energized parts or equipment.

3. Working on deenergized parts
   1. Circuit parts that cannot be deenergized using the procedures outlined in §1910.333(b)(2) must be treated as energized (as specified in §1910.333(b)(1)), regardless of whether the parts are, in fact, deenergized.
   2. Deenergized parts are required to be locked and tagged unless exempted under §§1910.333(b)(2)(iii)(C) or 1910.333(b)(2)(iii)(E), as discussed below. If so exempted, either a lock or tag is required.
      1. If a tag is used without a lock, it shall be supplemented by at least one additional safety measure that provides a level of safety equivalent to that obtained by the use of a lock. Examples of additional safety measures include the removal of an isolating circuit element, blocking of a controlling switch, or opening of an extra disconnecting device.
      2. A lock may be placed without a tag only under the following conditions:
         1. Only one circuit or piece of equipment is deenergized, and
         2. The lockout period does not extend beyond the work shift, and
         3. Employees exposed to the hazards associated with reenergizing the circuit or equipment are familiar with this procedure.

4. Verification of deenergization is mandatory. This verification must be done by a qualified person.
   1. The qualified person shall activate the equipment operating controls or otherwise verify that the equipment cannot be restarted.
   2. Test equipment shall be used to ensure that electrical parts and circuit elements have been deenergized.
   3. Testing instruments and equipment shall be visually inspected for external defects or damage before being used to determine deenergization (29 CFR 1910.334(c)(2)).
   4. For circuits over 600 volts nominal, the test equipment shall be checked for proper operation immediately before and immediately after the test.

5. Reenergization. The following requirements shall be met, in the order given, before circuits or equipment are reenergized, even temporarily.
   1. A qualified person shall conduct tests and visual inspections, as necessary, to verify that all tools, electrical jumpers, shorts, grounds, and other such devices have been removed so that the circuits and equipment can be safely energized.
   2. Potentially exposed employees shall be warned to stay clear of circuits and equipment prior to reenergizing.
   3. Each lock and tag shall be removed by the employee who applied it. However, if the employee is absent from the workplace, then the lock or tag may be removed by a qualified person designated to perform this task provided that the employer ensures:
      1. That the employee who applied the lock or tag is not available at the workplace,
      2. That the employee is informed that the lock or tag has been removed before he or she resumes work at the workplace, and
      3. That there is to be a visual determination that all employees are clear of the circuits and equipment prior to lock and tag removal.

6. Working on or near overhead power lines (§1910.333(c)(3))
   1. OSHA believes that the preferred method of protecting employees working near overhead power lines is to deenergize and ground the lines when work is to be performed near them.
   2. In addition to other operations, this standard also applies to tree trimming operations performed by tree workers who are not “qualified persons”. In this respect the exclusion in §1910.333(c)(1) applies only to “qualified persons” performing line-clearance tree trimming (trimming trees that are closer than 10 feet to overhead power lines).
   3. The standard does not prohibit workers who are not “qualified persons” from working in a tree that is closer than 10 feet to power lines so long as that person or any object he or she may be using, does not come within 10 feet of a power line. However, it would require “qualified persons” to perform the work if the worker or any object he or she may be using will come within 10 feet of an exposed energized part or if a branch being cut may be expected to come within 10 feet of an exposed energized part while falling from the tree. (See §1910.333(c)(3)(ii).)
   4. The purpose for the approach distance requirements is to prevent contact with and/or arcing from energized overhead power lines. The approach distance applies to tools used by employees as well as the employees themselves. Table S-5 calls for the following approach distances for qualified employees only:
      
      

      Voltage range (AC) (phase to phase)	Minimum approach distance
      300V and less	Avoid contact
      Over 300V, not over 750V	1 ft. 0 in. (30.5 cm)
      Over 750V, not over 2kV	1 ft. 6 in. (46 cm)
      Over 2kV, not over 15kV	2 ft. 0 in. (61 cm)
      Over 15kV, not over 37kV	3 ft. 0.in. (91 cm)
      Over 37kV, not over 87.5kV	3 ft. 6 in. (107 cm)
      Over 87.5kV, not over 121kV	4 ft. 0 in. (122 cm)
      Over 121kV, not over 140 kV	4 ft. 6 in. (137 cm)

      NOTE: Unqualified employees are required to adhere to the 10 ft. minimum.
      
      
   5. Employees working on or around vehicles and mechanical equipment, such as gin-pole trucks, forklifts, cherry pickers, garbage trucks, cranes and elevating platforms, who are potentially exposed to hazards related to equipment component contact with overhead lines, shall have been trained by their employers in the inherent hazards of electricity and means of avoiding exposure to such hazards.
   6. The standard for Electrical Safety-Related Work Practices can be applied with respect to electrical hazards related to any size, utilization or configuration of overhead power lines in general industry; e.g., residential power lines, remotely located overhead power lines, temporarily rigged overhead power lines, and overhead power lines along streets and alleys.

7. Portable ladders. Such ladders may not have conductive siderails in situations where the employee or the ladder could contact exposed energized parts. All ladders shall be in compliance with requirements of the standards found elsewhere in Part 1910.
   
   
8. Conductive apparel. Articles of jewelry and clothing such as watch bands, bracelets, rings, key chains, necklaces, metalized aprons, cloth with conductive thread, or metal headgear shall not be worn if there is a possibility of contacting exposed energized parts. However, such articles may be worn if they are rendered nonconductive by covering, wrapping, or other insulating means (§1910.333(c)(8)).
   
   
9. Housekeeping duties. The employer has the burden to provide adequate safeguards (such as insulating equipment or barriers) where live parts present an electrical contact hazard to employees who are performing housekeeping duties. Electrically conductive cleaning materials (such as steel wool, metalized cloth, and silicon carbide, as well as conductive liquid solutions) may not be used in proximity to energized parts unless procedures are followed which will prevent electrical contact.
   
   
10. Electrical safety interlocks. Interlocks found on panels, covers and guards are designed to deenergize circuits to prevent electric shock to persons using equipment or performing minor maintenance or adjustments and shall not be defeated or bypassed by an unqualified person.
    
    
11. Cord- and plug-connected equipment. Energized equipment here means either the equipment being plugged or the receptacle into which it is being plugged, or both (§1910.334(a)(5)(i)).
    
    
12. Eye and face protection. Section 1910.335(a)(1)(v) requires employees to wear protective equipment for the eyes or face wherever there is danger of injury to the eyes or face from electric arcs or flashes or from flying objects resulting from electrical explosion.

13. Insulated tool. This means a tool encased within material of composition and thickness that is recognized as electrical insulation.
    10. Enforcement/Citation guidance
        1. A deficiency in the employer’s program that could contribute to a potential exposure capable of producing serious physical harm or death shall be cited as a serious violation.
        2. The failure to train “qualified” and “unqualified” employees as required for their respective classifications shall normally be cited as a serious violation.
        3. Paperwork deficiencies in the safe work practice program where effective safe work practice procedures are in place shall be cited as other-than-serious.

Protective Measures

There are various ways of protecting people from the hazards caused by electricity, including insulation, guarding live parts, grounding, electrical protective devices, and safe work practices.

Insulation

One way to safeguard individuals from electrically energized wires and parts is through insulation. An insulator is any material with high resistance to electric current. To be effective, the insulation must be appropriate for the voltage, and the insulating material must be undamaged, clean, and dry.

Insulators — such as glass, mica, rubber, and plastic — are put on conductors to prevent shock, fires, and short circuits. Before employees prepare to work with electric equipment, it is always a good idea for them to check the insulation before making a connection to a power source to be sure there are no exposed wires. The insulation of flexible cords, such as extension cords, is particularly vulnerable to damage.

The insulation that covers conductors is regulated by Subpart S, Part 1910.302, Design Safety Standards for Electrical Systems. Subpart S generally requires that circuit conductors (the material through which current flows) be insulated to prevent people from coming into accidental contact with the current. Also, the insulation should be suitable for the voltage and existing conditions, such as temperature, moisture, oil, gasoline, or corrosive fumes. All these factors must be evaluated before the proper choice of insulation can be made.

Conductors and cables are marked by the manufacturer to show the maximum voltage and American Wire Gage size, the type letter of the insulation, and the manufacturer’s name or trademark. Insulation is often color coded. In general, insulated wires used as equipment grounding conductors are either continuous green or green with yellow stripes. The grounded conductors that complete a circuit are generally covered with continuous white or natural gray-colored insulation. The ungrounded conductors, or “hot wires,” may be any color other than green, white, or gray. They are often colored black or red.

Guarding

Live parts of electric equipment operating at 50 volts or more must be guarded against accidental contact. Guarding of live parts may be accomplished by:

• Location in a room, vault, or similar enclosure accessible only to qualified persons.
• Use of permanent, substantial partitions or screens to exclude unqualified persons.
• Location on a suitable balcony, gallery, or platform elevated and arranged to exclude unqualified persons; or
• Elevation of 8 feet (2.44 meters) or more above the floor.

Entrances to rooms and other guarded locations containing exposed live parts must be marked with conspicuous warning signs forbidding unqualified persons to enter.

Indoor electric wiring more than 600 volts and that is open to unqualified persons must be made with metal-enclosed equipment or enclosed in a vault or area controlled by a lock. In addition, equipment must be marked with appropriate caution signs.

Grounding

Grounding is another method of protecting employees from electric shock; however, it is normally a secondary protective measure. The ten-n “ground” refers to a conductive body, usually the earth, and means a conductive connection, whether intentional or accidental, by which an electric circuit or equipment is connected to earth or the ground plane.

By “grounding” a tool or electrical system, a low-resistance path to the earth is intentionally created. When properly done, this path offers sufficiently low resistance and has sufficient current carrying capacity to prevent the buildup of voltages that may result in a personnel hazard. This does not guarantee that no one will receive a shock, be injured, or be killed. It will, however, substantially reduce the possibility of such accidents, especially when used in combination with other safety measures discussed in this section.

There are two kinds of grounds required in OSHA’s electrical standard. One of these is called the “service or system ground.” In this instance, one wire, called “the neutral conductor” or “grounded conductor,” is grounded. In an ordinary low-voltage circuit, the white (or gray) wire is grounded at the generator or trans-former and again at the service entrance of the building. This type of ground is primarily designed to protect machines, tools, and insulation against damage.

To offer enhanced protection to the workers themselves, an additional ground, called the “equipment ground,” must be furnished by providing another path from the tool or machine through which the current can flow to the ground. This additional ground safeguards the electric equipment operator in the event that a malfunction causes the metal frame of the tool to become accidentally energized. The resulting heavy surge of current will then activate the circuit protection devices and open the circuit.

Circuit protection devices

Circuit protection devices are designed to automatically limit or shut off the flow of electricity in the event of a ground-fault, overload, or short circuit in the wiring system. Fuses, circuit breakers, and ground-fault circuit interrupters are three well known examples of such devices.

Fuses and circuit breakers are over-current devices that are placed in circuits to monitor the amount of current that the circuit will carry. They automatically open or break the circuit when the amount of current flow becomes excessive and therefore unsafe. Fuses are designed to melt when too much current flows through them. Circuit breakers, on the other hand, are designed to trip open the circuit by electro-mechanical means.

Fuses and circuit breakers are intended primarily for the protection of conductors and equipment. They prevent over-heating of wires and components that might otherwise create hazards for operators. They also open the circuit under certain hazardous ground-fault conditions.

The ground-fault circuit interrupter, or GFCI, is designed to shutoff electric power within as little as !/40 of a second. It works by comparing the amount of current going to electric equipment against the amount of current returning from the equipment along the circuit conductors. If the current difference exceeds six milliamperes, the GFCI interrupts the current quickly enough to prevent electrocution. The GFCI is used in high-risk areas such as wet locations and construction sites.

Safe work practices

Employees and others working with electric equipment need to use safe work practices. Electrical safety-related work practice requirements are contained in Subpart S, Sections 1910.331-1910.335. These include:

• Deenergizing electric equipment before inspecting or making repairs,
• Using electric tools that are in good repair,
• Using good judgment when working near energized lines, and
• Using appropriate protective equipment.
  
  

Training

To ensure that they use safe work practices, employees must be aware of the electrical hazards to which they will be exposed. Employees must be trained in safety-related work practices as well as any other procedures necessary for safety from electrical hazards.

Deenergizing electrical equipment

The accidental or unexpected sudden starting of electrical equipment can cause severe injury or death. Before ANY inspections or repairs are made — even on the so-called low-voltage circuits — the current must be turned off at the switch box and the switch padlocked in the OFF position. At the same time, the switch or controls of the machine or other equipment being locked out of service must be securely tagged to show which equipment or circuits are being worked on.

Maintenance employees should be qualified electricians who have been well instructed in lockout procedures. No two locks should be alike; each key should fit only one lock, and only one key should be issued to each maintenance employee. If more than one employee is repairing a piece of equipment, each should lock out the switch with his or her own lock and never permit anyone else to remove it. The maintenance worker should at all times be certain that he or she is not exposing other employees to danger.

Overhead lines

If work is to be performed near overhead power lines, the 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. Protective measures (such as guarding or insulating the lines) must be designed to prevent employees from contacting the lines.

Unqualified employees and mechanical equipment must stay at least 10 feet away from overhead power lines. If the voltage is more than 50,000 volts, the clearance must be increased by 4 inches for each additional 10,000 volts.

When mechanical equipment is being operated near overhead lines, employees standing on the ground may not contact the equipment unless it is located so that the required clearance cannot be violated even at the maximum reach of the equipment.

Protective equipment

Employees whose occupations require them to work directly with electricity must use the personal protective equipment required for the jobs they perform. This equipment may consist of rubber insulating gloves, hoods, sleeves, matting, blankets, line hose, and industrial protective helmets.

Tools

To maximize his or her own safety, an employee should always use tools that work properly. Tools must be inspected before use, and those found questionable, removed from service and properly tagged. Tools and other equipment should be regularly maintained. Inadequate maintenance can cause equipment to deteriorate, resulting in an unsafe condition.

Tools that are used by employees to handle energized conductors must be designed and constructed to withstand the voltages and stresses to which they are exposed.

Good judgment

Perhaps the single most successful defense against electrical accidents is the continuous exercising of good judgment or common sense. All employees should be thoroughly familiar with the safety procedures for their particular jobs. When work is performed on electrical equipment, for example, some basic procedures are:

• Have the equipment deenergized;
• Ensure that the equipment remains deenergized by using some type of lockout and tag procedure;
• Use insulating protective equipment; and
• Keep a safe distance from energized parts.

The control of electrical hazards is an important part of every safety and health program. The measures suggested in this section should be of help in establishing such a program of control. The responsibility for this program should be delegated to individuals who have a complete knowledge of electricity, electrical work practices, and the appropriate OSHA standards for installation and performance.

Everyone has the right to work in a safe environment. Through cooperative efforts, employers and employees can learn to identify and eliminate or control electrical hazards.

Burns and Other Injuries

The most common shock-related injury is a burn. Burns suffered in electrical accidents may be of three types: electrical burns, arc burns, and thermal contact burns.

Electrical burns

Electrical burns are the result of the electric current flowing through tissues or bone. Tissue damage is caused by the heat generated by the current flow through the body. Electrical burns are one of the most serious injuries you can receive and should be given immediate attention.

Arc or flash burns

Arc or flash burns, on the other hand, are the result of high temperatures near the body and are produced by an electric arc or explosion. They should also be attended to promptly.

Thermal contact burns

Finally, thermal contact burns are those normally experienced when the skin comes in contact with hot surfaces of overheated electric conductors, conduits, or other energized equipment. Additionally, clothing may be ignited in an electrical accident and a thermal burn will result. All three types of burns may be produced simultaneously.

Electric current, even as low as three milliamperes, can also cause injuries of an indirect or secondary nature in which involuntary muscle reaction from the electric shock can cause bruises, bone fractures, and even death resulting from collisions or falls. In some cases, injuries caused by electric shock can be a contributory cause of delayed fatalities.

In addition to shock and burn hazards, electricity poses other dangers. For example, when a short circuit occurs, hazards are created from the resulting arcs. If high current is involved, these arcs can cause injury or start a fire. Extremely high-energy arcs can damage equipment, causing fragmented metal to fly in all directions. Even low-energy arcs can cause violent explosions in atmospheres that contain flammable gases, vapors, or combustible dusts.

How Shocks Occur | Electrical Hazards

Electricity travels in closed circuits, and its normal route is through a conductor. Electric shock occurs when the body becomes a part of the electric circuit. The current must enter the body at one point and leave at another. Electric shock normally occurs in one of three ways. Individuals, while in contact with the ground, must come in contact with:

1. Both wires of the electric circuit,
2. One wire of an energized circuit and the ground, or
3. A metallic part that has become “hot” by contact with an energized conductor.

The metal parts of electric tools and machines may become energized if there is a break in the insulation of the tool or machine wiring. The worker using these tools and machines is made less vulnerable to electric shock when there is a low-resistance path from the metallic case of the tool or machine to the ground. This is done through the use of an equipment grounding conductor, a low-resistance wire that causes the unwanted current to pass directly to the ground, thereby greatly reducing the amount of current passing through the body of the person in contact with the tool or machine. If the equipment grounding conductor has been properly installed, it has a low resistance to ground, and the worker is protected.

Severity of the shock

The severity of the shock received when a person becomes a part of an electric circuit is affected by three primary factors:

• Amount of current flowing through the body (measured in amperes),
• Path of the current through the body, and
• Length of time the body is in the circuit.

Other factors that may affect the severity of shock are the frequency of the current, the phase of the heart cycle when shock occurs, and the general health of the person.

The effects of electric shock depend upon the type of circuit, its voltage, resistance, current, pathway through the body, and duration of the contact. Effects can range from a barely perceptible tingle to immediate cardiac arrest. Although there are no absolute limits or even known values that show the exact injury from any given current, the table below shows the general relationship between the degree of injury and amount of current for a 60-cycle hand-to-foot path of one second’s duration of shock.

The table also illustrates that a difference of less than 100 milliamperes exists between a current that is barely perceptible and one that can kill. Muscular contraction caused by stimulation may not allow the victim to free himself or herself from the circuit, and the increased duration of exposure increases the dangers to the shock victim. For example, a current of 100 milliamperes for three seconds is equivalent to a current of 900 milliamperes applied for .03 seconds in causing ventricular fibrillation. The so-called low voltages can be extremely dangerous because, all other factors being equal, the degree of injury is proportional to the length of time the body is in the circuit.

LOW VOLTAGE DOES NOT IMPLY LOW HAZARD!

A severe shock can cause considerably more damage to the body than is visible. For example, a person may suffer internal hemorrhages and destruction of tissues, nerves, and muscles. In addition, shock is often only the beginning in a chain of events. The final injury may well be from a fall, cuts, bums, or broken bones.

Effects of electric current in the human body 

Current	Reaction
1 Milliampere	Perception level. Just a faint tingle.
5 Milliamperes	Slight shock felt; not painful but disturbing. Average individual can let go. However, strong involuntary reactions to shocks in this range can lead to injuries.
6-25 Milliamperes (women)	Painful shock, muscular control is lost.
9-30 Milliamperes (men)	This is called the freezing current or “let-go” range.
50-150 Milliamperes	Extreme pain, respiratory arrest, severe muscular contractions[*]. Individual cannot let go. Death is possible.
1,000-4,300 Milliamperes	Ventricular fibrillation. (The rhythmic pumping action of the heart ceases.) Muscular contraction and nerve damage occur. Death is most likely.
10,000-Milliamperes	Cardiac arrest, severe burns and probable death.
[*]If the extensor muscles are excited by the electric shock, the person may be thrown away from the circuit. Source: W.B. Kouwenhoven, Human Safety and Electric Shock, Electrical Safety Practices, Monograph, 112, Instrument Society of America, p. 93. (Papers delivered at the third presentation of the Electrical Safety Course given in Wilmington, DE, in November 1968.)