Chapter 1: Working on Lines and Equipment - Working on the Line - Possible Test Questions - Week 7 Flashcards
Categories of linework:
- Construction
- Maintenance
- Repair
The two methods for working on a power delivery system:
- Energized
- De-energized
List a few specialized live-line tools:
- Hot Sticking
- Rubber Gloving (Including use of rubber sleeves)
- Barehanding
OSHA Linework is governed by:
- Construction or general industry regulations
De-Energized work involved protection against both:
-Normal and abnormal sources of energy
Proper steps to de-energize:
- Disconnect
- Test
- Properly Ground
The two grounding procedures:
- Equipotential Zone (EPZ)
- Bracket Grounding
Equipotential Zone (EPZ) Grounding:
- Grounding is the preferred method for protecting the lineworker
Bracket Grounding:
- Is used to trip out the circuit as quickly as possible
The terms “voltage” and “potential” will be:
- used interchangeable throughout this course
Current will divide and take:
- every available path to objects of different potential
Insulate and Isolate:
- The only way to completely prevent current flow through the lineworker
Protective grounding and bonding are effective if they meet the following two objectives:
- Minimize the time it takes to trip the circuit
- Limit the current flow and voltage drop across the lineworker’s body.
When performing energized work, lineworkers follow three principals to manage current:
- 1) Insulate-use hot sticks, rubber gloves/sleeves, and rubber/plastic cover-up equipment to shield against current flow.
2) Isolate-create physical separation from any object of different potential. For example, an insulated aerial lift or insulated platform helps to isolate the worker’s feet from differences of potential. - 3) Protect against second point of contact-arrange the insulation and isolate the workers and tools so that anything that has a different potential than the item to be worked cannot be reached from the work position.
The second point of contact is defined as:
- “the point at which current leaves
the body during simultaneous contact between two or more objects of
different potential.”
The Pain Scale:
- DETECTABLE: (1-5 milliamps (mA) OR .1%-.5% of 1 amp) Feeling of warmth or a slight tingle; little or no body reaction.
- PAINFUL: (9-15 mA OR .9%-1.5% of 1 amp) Feeling of clear discomfort; minor body movement.
- LET GO: (16-100 mA OR 1.6%-10% of 1 amp) Instant pain; immediate letting go or moving away from the contact.
- VENTRICULAR FIBRILLATION OF THE HEART (V-FIB): (100-700 mA OR 10%-70% of 1 amp): Disabled; heart is unable to function properly.
- BURNING OF THE SKIN AND ORGANS: (1 amp and higher) Significant damage
All Employees exposed to electrical hazards must use approved:
- protective equipment
- OSHA
Clearance:
- Disconnecting a line, line section, or equipment that is being worked on