Middlebury

 

Electrical Safety and Related Work practices

Bottom of Form
MIDDLEBURY COLLEGE

Electrical Safety and Related Work Practices
29CFR 1910.301 through 1910.335

Revised: 11/03

Reviewed: 7/26/06

Table of Contents

Scope  1910.331                                    3
Qualified & Unqualified                                                                     4

Training 1910.332                                                                             4
Occupations that may require training                                                4

Selection and use of work practices                                                 5
Deenergized parts                                                                                5
Energized parts                                                                                    5
Lockout and tagging                                                                             5
Procedures                                                                                            5
Application of locks and tags                                                               6
Verification of deenergized conditions                                                6
Reenergizing equipment                                                                      6
Working on or near exposed energized parts & equipment                7
Overhead lines                                                                                     7
Unqualified persons                                                                             7
Qualified persons                                                                                 7
Vehicular and mechanical equipment                                                  8
Illumination                                                                                          8
Confined or enclosed work spaces                                                       8
Conductive materials and equipment                                                   8
Portable ladders                                                                                    8
Conductive apparel                                                                              8
Housekeeping duties                                                                            8
Interlocks                                                                                             9

Use of equipment  1910.334                                                              9
Portable electric equipment                                                                 9
Handling                                                                                              9
Visual inspection                                                                                9
Grounding-type equipment                                                                9
Conductive work locations                                                                10
Connecting attachment plugs                                                            10
Electric power and lighting circuits                                                  10
Test instruments and equipment                                                       10
Occasional use of flammable ignitable materials                              10

Safeguards for personnel protection                                             11
Use of protective equipment                                                             11
General protective equipment and tools                                           11
Alerting techniques                                                                           11
This electrical safety document is taken from the VOSHA Electrical Standards but not in its entirety.  You should consult the standards directly if you have any specific concerns or questions.  The sections covered here are 1910.331 through 1910.335 as it relates to Safety-Related Work practices.  Lockout/tagout is covered in more detail under another College policy.

1910.331  SCOPE

Subpart S – Electrical, addresses electrical safety requirements that are necessary for the practical safeguarding of employees in their workplace and is divided into four major divisions:

1. Design safety standards for electrical systems.  These regulations are contained in 1910.302 through 1910.330.  Sections 1910.302 through 1910.308 contain design safety standards for electrical utilization systems.  Included in this category are all electrical equipment and installations used to provide electric power and light for employer workplace.  Section 1910.309 through 1910.330 are reserved for possible future design standards for other electrical systems.  .

2.  Safety-related work practices.  These regulations will be contained in 1910.331 
through 1910.360.

3. Safety-related maintenance requirements.  These regulations will be contained in 
1910.361 through 1910.380.

4. Safety requirements for special equipment.  These regulations will be contained in 
1910.381 through 1910.398.

The provisions of 1910.331 through 1910.335 cover electrical safety work practices for both qualified persons (those having training in avoiding the electrical hazards of working on or near exposed energized parts) and unqualified persons (those with little or no such training) working on, near, or with the following installations:

(1) Premises wiring.  Installations of electric conductors and equipment within or on buildings or other structures, and on other premises such as yards, carnival, parking, and other lots, and industrial substations.

(2) Wiring for connection to supply.  Installations of conductors that connect to the supply of electricity; and

(3) Other wiring.  Installations of other outside conductors on the premises.

(4) Optical fiber cable.  Installation of optical fiber cable where such installations are made along with electric conductors.

Qualified & Unqualified Persons

A qualified person is one familiar with the construction and operation of the equipment and the hazards involved. 

Whether a person is considered to be a “qualified person” will depend upon 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. 

Excluded work by qualified persons on or directly associated with the following installations:
(1) Generation, transmission, and distribution installations.
(2) Communications installations
(3) Installations in vehicles
(4) Railway installations

For more detail consult 29CFR 1910.331

Training  (1910.332)

The training requirements in this section apply to employees who face a risk of electric shock that is not reduced to a safe level by the electrical installation requirements of 1910.303 through 1910.308.

Employees shall be trained in practices addressed in this policy.  Training will be done at time of employment and annually thereafter.  Employees shall be trained in and familiar with the safety related work practices required by 1910.331 through 1910.335 that pertain to their respective job assignments.

Qualified persons, additional requirements.  Those permitted to work on or near exposed energized parts shall, at a minimum, be trained in and be familiar with the following:
a) Skills and techniques necessary to distinguish exposed live parts from other parts of 
electrical equipment.
b) The skill and techniques necessary to determine the normal voltage of exposed live 
parts, and….
c) The clearance distance specified in 1910.335c, and the corresponding voltage to  
which the qualified person will be exposed.

Occupations That May Require Training:

Blue collar supervisors
Electrical and electronic engineers
Electrical and electronic equipment assemblers
Electrical and electronic technicians
Electricians
Industrial machine operators
Material handling equipment operators
Mechanics and repairers
Painters
Riggers
Stationary engineers
Welders

Workers in these groups do not need to be trained if their work or the work of those they supervise does not bring them or the employees they supervise close enough to exposed parts of electric circuits operating at 50 volts or more to ground for a hazard to exist.

Selection and use of work practices  (1910.333)

Safety-related work practices shall be employed to prevent electric shock or other injuries resulting from either direct or indirect electrical contacts, when work is performed near or on equipment or circuits which are or may be energized.  The specific safety-related work practices shall be consistent with the nature and extent of the associated electrical hazards.

Deenergized parts.  Live parts to which an employee may be exposed shall be deenergized before the employee works on or near them, unless the employer can demonstrate that deenergizing introduces additional or increased hazards or is infeasible due to equipment design or operational limitations.  Live parts that operate at less that 50 volts to ground need not be deenergized if there will be no increased exposure to electrical burns or to explosion due to electrical arcs.

Energized parts.  If the exposed live parts are not deenergized, other safety-related work practices shall be used to protect employees who may be exposed to the electrical hazards involved.  Such work practices shall protect employees against contact with energized circuit parts directly with any part of their body or indirectly through some other conductive object.  The work practices that are used shall be suitable for the conditions under which the work is to be performed and for the voltage level of the exposed electrical conductors or circuit parts.  Specific work practice requirements are detailed in paragraph (c) of this section.

“Lockingout andTagging”  While any employee is exposed to contact with parts of fixed electrical equipment or circuits which have been deenergized, the circuits energizing the parts shall be locked out or tagged or both in accordance with this policy and VOSHA.

“Procedures”  The College will maintain a written copy of the procedures and shall make it available for inspection by VOSHA.

1. Safe procedures for deenergizing circuits and equipment shall be determined before circuits or equipment are deenergized.
2. The circuits and equipment to be worked on shall be disconnected from all electrical energy sources.  Control circuit devices, such as push buttons, selector switches, and interlocks, may not be used as the sole means for deenergizing circuits or equipment.  Interlocks for electric equipment may not be used as a substitute for lockout and tagging procedures.
3. Stored electric energy which might endanger personnel shall be released.  Capacitors shall be discharged and high capacitance elements shall be short-circuited and grounded, if the stored electric energy might danger personnel.
4. Stored non-electrical energy in devices that could reenergize electric circuit parts shall be blocked or relieved to the extent that the circuit parts could not be accidentally energized by the device.

“Application of locks and tags”  A lock and tag shall be placed on each disconnecting means used to deenergize circuits and equipment on which work is to be performed.  The lock shall be attached so as to prevent persons from operating the disconnected means unless they resort to undue force or the use of tools.  Each tag shall contain a statement prohibiting unauthorized operation of the disconnecting means and removal of the tag.

If a lock cannot be applied, or of the department can demonstrate to EH&S that tagged procedures will provide a level of safety equivalent to that obtained by the use of a lock, a tag may be used without a lock.  However, a tag without a lock shall be supplemented by at least one additional safety measure that provides a level of safety equivalent to that obtained by 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.

“Verification of deenergized condition.”  A qualified person shall operate the equipment operating controls or otherwise verify that the equipment cannot be restarted.  A qualified person shall use test equipment to test the circuit elements and electrical parts of the equipment to which employees will be exposed and shall verify that the circuit elements and equipment parts are deenergized.  The test shall also determine if any energized condition exists as a result of inadvertently induced voltage or unrelated voltage backfeed even though specific parts of the circuit have been deenergized and presumed to be safe.  If the circuit to be tested is over 600 volts, nominal, the test equipment shall be checked for proper operation immediately after the test.

“Reenergizing equipment.”  These requirements shall be met, in the order given, before circuits or equipment are reenergized, even temporarily. 

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.

Employees exposed to the hazards associated with reenergizing the circuit or equipment shall be warned to stay clear of circuits and equipment.  There shall be a visual determination that all employees are clear of the circuits and equipment.  Each lock and tag shall be removed by the employee who applied it or under his/her direct supervision.  However, if this employee is absent from the workplace, then the lock or tag may be removed according to the Lockout/Tagout policy.

“Working on or near exposed energized parts and equipment.”  This applies to work performed on exposed live parts (involving either direct contact or by means of tools or materials) or near enough to them for employees to be exposed to any hazard they present.

Only qualified persons may work on electric circuit parts or equipment that have not been deenergized.  Such persons shall be capable of working safely on energized circuits and shall be familiar with the proper use of special precautionary techniques, personal protective equipment, insulating and shielding materials, and insulated tools.

“Overhead lines.”  If work is to be performed near overhead lines, the lines shall be deenergized and grounded, or other protective measures shall be provided before work is started.  If the lines are to be deenergized, arrangements shall be made with the person or organization that operates or controls the electric circuits involved to deenergize and ground them.  If protective measures, such as guarding, isolating, or insulating, are provided, these precautions shall prevent employees from contacting such lines directly with any part of their body or indirectly through conductive materials, tools, or equipment.

“Unqualified persons.”  When an unqualified person is working in an elevated position near overhead lines, or on the ground, the location shall be such that the person and the longest conductive object he /she may contact cannot come closer to any unguarded, energized overhead line than the following distance:

1. For voltages to ground 50kV or below – 10 feet
2. For voltages to ground over 50kV – 10 feet plus 4 inches for every 10kV over
50kV.  *

“Qualified persons.”  When a qualified person is working in the vicinity of overhead lines, whether in an elevated position or on the ground, the person may not approach or take any conductive object (without an approved insulating handle) closer than 4ft. 6 in. for up to 140kV unless:
1. The person is insulated from the energized part (gloves, with sleeves if necessary, rated for the voltage involved are considered to be insulation of the person from the energized part on which work is performed), or
2. The energized part is insulated both from all other conductive objects at a different potential and from the person, or
3. The person is insulated from all conductive objects at a potential different from that of the energized part.

*  Consult the VOSHA standards for specific distances for smaller voltage range.

“Vehicular and mechanical equipment.”  Any vehicle or mechanical equipment capable of having parts of its structure elevated near energized overhead lines shall be operated so that a clearance of 10 ft. is maintained.  If the voltage is higher than 50kV, the clearance shall be increased 4 in. for every 10kV over that voltage.  However, you may consult the standard for exceptions to this rule.  In addition the person in charge shall insure that nobody is in close proximity of the lift vehicle.

“Illumination”  Employees may not enter spaces containing exposed energized parts, unless illumination is provided that enables the employee to perform the work safely.
Where lack of illumination or an obstruction precludes observation of the work to be performed, employees may not perform tasks near exposed energized parts.  Employees may not reach blindly into areas which contain energized parts.

“Confined or enclosed work spaces.”  When an employee works in a confined or enclosed space (such as a manhole or vault) that contains exposed energized parts, the employer shall provide, and the employee shall use, protective shields, protective barriers, or insulating materials as necessary to avoid inadvertent contact with these parts.  Doors, hinges panels, and the like shall be secured to prevent their swing into an employee and causing the employee to contact energized parts.

“Conductive materials and equipment.”   Conductive materials and equipment that are in contact with any part of an employee’s body shall be handled in a manner that will prevent them from contacting exposed energized conductors or circuit parts.  If an employee must handle long dimensional conductive objects (such as ducts and pipes) in areas with exposed live parts, the employer shall institute work practices (such as the use of insulation, guarding, and material handling techniques) which will minimize the hazard.

“Portable ladders.”  Portable ladders shall have nonconductive siderails if they are to be used where the employee or the ladder could contact exposed energized parts.

“Conductive apparel.”  Conductive articles of jewelry and clothing (such as watch bands, bracelets, rings, key chains, necklaces, metalized aprons. Cloth with conductive thread, or metal headgear) may not be worn if they might contact energized parts.  However, such articles may be worn if they are rendered nonconductive by covering, wrapping, or other insulating means.

“Housekeeping duties.”  Where live parts present an electrical contact hazard, employees may not perform housekeeping duties at such close distances to the parts that there is a possibility of contact, unless adequate safeguards (such as insulating equipment or barriers) are provided.  Electrically conductive cleaning materials (including conductive solids 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.

“Interlocks.”  Only a qualified person following the requirements of this section may defeat and electrical safety interlock, and then only temporarily while he or she is working on the equipment.  The interlock system shall be returned to its operable condition when the work is completed.

1910.334  Use of equipment

“Portable electric equipment”  This applies to the use of cord-and-plug-connected equipment, including flexible cord sets (extension cords).

“Handling “.   Portable equipment shall be handled in a manner which will not cause damage.  Flexible electric cords connected to equipment may not be used for raising or lowering the equipment.  Flexible cords may not be fastened with staples or otherwise hung in such a fashion as could damage the outer jacket or insulation.

“Visual inspection”  Portable cord and plug connected equipment and extension cords shall be visually inspected before use on any shift for eternal defects and for evidence of possible internal damage.  Cord and plug connected equipment and flexible cord sets which remain connected once they are put in place and are not exposed to damage need not be visually inspected until they are relocated.

If there is a defect or evidence of damage that might expose an employee to injury, the defective or damaged item shall be removed from service, and no employee may use it until repairs and tests necessary to render the equipment safe have been made.

When the attachment plug is to be connected to a receptacle, the relationship of the plug and receptacle contacts shall first be checked to ensure that they are of proper mating configurations.

“Grounding-type equipment”  A flexible cord set used with grounding type equipment shall contain an equipment grounding conductor.

Attachment plugs and receptacles may not be connected or altered in a manner which would prevent proper continuity of the equipment grounding conductor at the point where plugs are attached to receptacles.  Additionally, these devices may not be altered to allow the grounding pole of a plug to be inserted into slots intended for connection to the current-carrying conductors.

Adapters which interrupt the continuity of the equipment grounding connection may not be used.

“Conductive work locations”   Portable electric equipment and flexible cords used in highly conductive work locations, or job locations where the employees are likely to contact water or conductive liquids, shall be approved for these locations.

“Connecting attachment plugs”  Employees’ hands may not be wet when plugging and unplugging flexible cords and cord-and plug-connected equipment, if energized equipment is involved.

Energized plug and receptacle connections may be handled only with insulated protective equipment if the condition of the connection could provide a conducting path to the employee’s hand.  Locking-type connectors shall be properly secured after connection.

“Electric power and lighting circuits”   Routine opening and closing of circuits.  Load rated switches, circuit breakers, or other devices specifically designed as disconnecting means shall be used for the opening, reversing, or closing of circuits under load conditions.  Cable connectors not of the load-break type, fuses, terminal lugs, and cable splice connections may not be used for such purposes, except in an emergency.

After a circuit is deenergized by a circuit protective device, the circuit may not be manually reenergized until it has been determined that the equipment and circuit can be safely energized.  The repetitive manual closing of circuit breakers or reenergizing circuits through replaced fuses is prohibited.

Overcurrent protection of circuits and conductors may not be modified, even on a temporary basis, beyond that allowed by 1910.3049e0, the installation safety requirements for overcurrent protection.

“Test instruments and equipment”  Only qualified persons may perform testing work on electric circuits or equipment.  Test instruments and equipment and all associated test leads, cables, power cords, probes, and connectors shall be visually inspected for external defects and damage before the equipment is used.  If there is a defect or evidence of damage that might expose an employee to injury, the defective or damaged items shall be removed from service, and no employee may use it until repairs and tests necessary to render the equipment safe have been made.

Test instruments and equipment and their accessories shall be rated for the circuits and equipment to which they will be connected and shall be designed for the environment in which they will be used.

“Occasional use of flammable or ignitable materials”  Where flammable materials are present only occasionally, electric equipment capable of igniting them shall not be used, unless measures are taken to prevent hazardous conditions from developing.  Such materials include, but are not limited to: flammable gases, vapors, or liquids; combustible dust; and ignitable fibers or flyings.

You should note that electrical installation requirements for locations where flammable materials are present on a regular basis are contained in 1910.307.

1910.335 Safeguards for personnel protection

“Use of protective equipment”  Employees working in areas where there are potential electrical hazards shall be provided with, and shall use, electrical protective equipment that is appropriate for the specific parts of the body to be protected and for the work to be performed.  Protective equipment shall be maintained in a safe, reliable condition and shall be periodically inspected or tested, as required by 1910.137.

If the insulating capability of protective equipment may be subject to damage during use, the insulating material shall be protected.  (Like using an outer covering of leather)
Employees shall wear nonconductive head protection wherever there is a danger of head injury from electric shock or burns due to contact with an exposed energized parts.  The hard hats should have a class B rating.

Employees shall wear protective equipment for eyes or face wherever there is danger of injury to the eye or face from electric arcs or flashes or from flying objects resulting from electrical explosion. 

“General protective equipment and tools”  When working near exposed energy conductors or circuit parts, each employee shall used insulated tools or handling equipment if the tools or handling equipment might make contact with such conductors or parts.  If the insulating capability of the insulated tools or handling equipment is subject to damage, the insulating material shall be protected.

Fuse handling equipment, insulated for the circuit voltage, shall be used to remove or install fuses when the fuse terminals are energized.  Ropes and handlines used near exposed energized parts shall be nonconductive.

Protective shields, protective barriers, or insulating materials shall be used to protect each employee from shock, burns, or other electrically related injuries while that employee is working near exposed energized parts which might be accidentally contacted or where dangerous electric heat or arcing might occur When normally enclosed live parts are exposed for maintenance or repair, they shall be guarded to protect unqualified persons from contact with live parts.

“Alerting techniques”  The following alerting techniques shall be used to warn and protect employees from hazards which could cause injury due to electric shock, burns, or failure of electrical equipment parts.  Safety signs, safety symbols, or accident prevention tags shall be used where necessary to warn employees about electrical hazards which may endanger them, as required by 1910.145.

Barricades shall be used in conjunction with safety signs where it is necessary to prevent or limit employee access to work areas exposing employees to uninsulated energized conductors or circuit parts.  Conductive barricades may not be used where they might cause an electrical contact hazard.

If signs and barricades do not provide sufficient warning and protection from electrical hazards, an attendant shall be stationed to warn and protect employees.

1