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Metro North Class “C” Employees Electrical Safety Training

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Presentation on theme: "Metro North Class “C” Employees Electrical Safety Training"— Presentation transcript:

1 Metro North Class “C” Employees Electrical Safety Training
Welcome to this presentation We hope you enjoy it. Metro North Training Department 3/13/02 Course # 70A10

2 Introduction OSHA and the NYDOL, which regulate electrical transmission and distribution systems, such as our third rail traction distribution system, issue guidelines for the minimum safe distance an employee can approach to live, exposed energized parts.

3 Introduction The purpose of this module is to qualify non-electrical Metro-North employees as Class “C” employees and allow them to work up to 1 foot (12”) from the exposed energized third rail system.

4 Objectives During this session the trainee will:
Identify exposed live parts of third rail system components. Review the hazards of electricity. Determine the nominal voltage of exposed live parts and wires. Review the minimum approach distances corresponding to the voltage to which the qualified employee will be exposed. Review the use of special protective equipment such as rubber blankets.

5 Third rail system components
Exposed energized parts: Third Rail End Approach (Nosepiece) Rail Lead Pothead (terminator)

6 Third rail system components
Not exposed energized parts, but part of the third rail system: Bracket Bracket Tie Capping Sectionalizing Switch Impedance Bond [Impedance bond lead wires are exothermically bonded (cadweld) to the running rail. If the lead breaks off, the end will become exposed].

7 The Third Rail System The Third Rail System consists of a 700-Volt positive 3rd rail for each track, and the running rail, which is the 700-Volt negative part of the system. The electrical energy, or voltage, between the running rails and the 3rd rail is 700 Volts. The third rail is considered an exposed conductor; energized at 700 Volts.

8 The Third Rail Covering
Covering (capping) on third rail is not insulation, and must not be depended upon for protection against shock from contact with energized (live) third rail Do not step, sit, walk upon, or brush against the third rail.

9 Hazards Of Electricity
The hazards of electricity are broken down into three types: 1.Shock 2.Arc 3.Blast

10 Hazards Of Electricity
.1. SHOCK Electricity travels in closed circuits, and its normal route is through a conductor. 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.

11 The Severity of Shock The severity of shock received when a person becomes a part of an electric circuit is affected by three primary factors: the amount of current flowing through the body (measured in amperes) the path of the current through the body the length of time the body is in the circuit

12 The Effects of Shock Effects can range from a barely perceptible tingle to immediate cardiac arrest. A difference of less than 100 milliamperes or .1 amp exists between a current that is barely perceptible and one that can kill. .1 amp is recognized as lethal dosage!

13 The Effects of Shock Electricity can travel through different paths in the body: nervous system circulatory system skeletal system muscle It may take only one route, or all four, and do extraordinary damage along the way. The most common shock related injury is a burn. Burns in electrical accidents may be of three types: electrical burns arc burns thermal contact burns

14 Electrical Burns Electrical burns are the result of the electric current flowing through the tissues or bones. Tissue damage is caused by the heat generated by the currently flow through the body. Electrical burns are one of the most serious injuries you can receive and should be given immediate attention. Since the most severe burning is likely to be on the inside, what may appear at first to be a small surface wound could, in fact, be an indication of severe internal burns.

15 Ways to be shocked by the third rail:
Five ways to be shocked by the third rail: Contact with the third rail and the running rail. Contact with the third rail and equipment on the running rail Contact with two third rails if difference of potential (voltage) exists. Contact with a metal object or other conductor (water) that is in contact with the third rail and the running rail. I.E. holding a tool or material that contacts both the third rail and running rail

16 Insulated Tools Metro North Safety Rule 3345 states :
"When used on or near tracks equipped with third rail, the following tools must be insulated with approved material: claw bar, lining bar, jack bar, tie, timber, rail tongs, speed and track wrenches, and rail fork. Insulation should be inspected before each use to insure it is not cut, gouged split or otherwise ineffective."

17 Insulated Tools Metro North Safety Rule #9271 states:
“Insulated tools are to be regarded as an added precaution in the event of an accidental contact with energized electrical appurtenances; they are never to be considered adequate protection against electric shock in lieu of appropriate safety practices."

18 Hazards Of Electricity
2. Arc Arc burns make up a substantial portion of the injuries from electrical malfunction. The electric arc between metals can be up to 35,000 degrees Fahrenheit, which is about four times hotter than the surface of the sun. Workers several feet from the source of the arc can receive severe or fatal burns.

19 Arc Electric arcs can occur due to poor electrical contact or failed insulation. Electrical arcing is caused by the passage of substantial amounts of current through the vaporized terminal material-usually metal or carbon.

20 Hazards Of Electricity
3. Blast The third source of possible hazard is the blast associated with an electric arc. This blast comes from the pressure developed by the near instantaneous heating of the air surrounding the arc and from the expansion of the metal as it is vaporized. These pressures can be great enough to hurl people, metal objects and tools considerable distances. Another hazard associated with blast is hurling of molten droplets, which can cause skin contact burning.

21 Minimum Approach Distance:
The closest distance an employee (person) is permitted to approach an exposed energized line/or part. Unqualified Employee (Person) – 10 feet –

22 Minimum Approach Distances:
Qualified Employee/Person (Class “A”, Class “B”, and Class “C”)

23 Minimum Approach Distance:
The minimum approach distance for a qualified Class “C” employee to live energized third rail components is twelve inches:

24 Qualified Employees: QUALIFIED EMPLOYEES:
Employees who have received training and have demonstrated proficiency in the work practices involved in their respective job assignments; and, have passed the required examinations and have been approved by proper authority to work in the vicinity of exposed energized parts.

25 Qualified Employees: CLASS “A”:
Power Department employees who have been instructed and certified on electrical hazards and are qualified to erect, repair, and maintain electrical apparatus, catenary and third rail, and to supervise and protect other persons performing work in electrified territory.These employees are also qualified to use hot line tools and work on circuits energized to 30,000 V.

26 Qualified Employees: CLASS“B”:
1. Power Department and Structures Electricians who have been instructed and certified on electrical hazards and are qualified to install, maintain and repair electrical apparatus under their jurisdiction 2. Mechanical Department employees who have been instructed and certified on electrical hazards and are permitted to work on top of equipment under the conditions hereafter authorized in these instructions, and are qualified to install third rail protection blankets. 3.C & S employees who have been instructed and certified on electrical hazards and are qualified to install, maintain and repair signal apparatus under their jurisdiction, and are qualified to install third rail protection blankets.

27 Qualified Employees: CLASS “C”: Track & Structures, Operations Services, and any other employee who has been instructed and certified on electrical hazards and whose duties require them to work in close proximity to the third rail.

28 Extended Reach: EXTENDED REACH: A working distance measured between the employee and the end of the tool, equipment or material being used and the exposed energized (live) parts. *Minimum approach distance must not be breached by extended reach of tool, equipment or material.

29 Rubber Insulating Blankets:
Rubber blanket protection is a method of changing the minimum approach distance. It is a means of affording employees protection from the electrical hazards of energized, or live third rail, allowing the employee to breech the minimum approach distance. Allows employee to work between the running rail and the adjacent energized (live) third rail. Only qualified Class “A” or “B” employees may install rubber insulating blankets on energized (live) third rail.

30 Rubber Insulating Blankets:
Rubber insulating blankets are specialty items and manufactured to industry standards. Defined as a protective rubber insulating blanket, compliant with ASTM (American Society for Testing and Materials) D1048 specifications, used to provide personal protection in the event of accidental contact with exposed energized (live) parts. Intentional contact with rubber insulating blankets should be avoided.

31 Rubber Insulating Blanket:
Metro North Safety Rule # 9265 “No work should be performed between the field side of the track rail and energized third rail without rubber mat protection applied by a qualified employee.”

32 The End This concludes The Metro North Class “C” Electrical Training Module. We hope you enjoyed it! Please keep on clicking your mouse to let us know that you took the test. After you enter your ID into the database, you can send us your comments and / or questions. ANY QUESTIONS OR COMMENTS - US - CLICK HERE LET US KNOW YOU TOOK THE TEST CLICK HERE Metro North Training Department 3/13/02 Course # 70A10


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