Protective line devices, cares and use Flashcards
What is the common equipment to use to perform live maintenance
Rubber Gloves
Other than rubber gloves all other rubber cover up equipment are intended for what
protection against an accidental brush contact
what is the definition of a second point of contact
Is defined as the point where current leaves the body if contact is made with a hot circuit
What is OSHA 1910.137
Electrical Protective equipment
what does Osha 1910.137 Electrical protective Equipment use as refernce
ATSM (American Society for Testing and Materials) protective equipment standards
What are rubber sleeves protective standard code
ASTM D 1051
What are insulating blankets protective standard code
ASTM D 1048
What are insulating mats protective standard code
ASTM D 178
What are rubber hoods protective standard code
ASTM D 1049
What are Line hose protective standard code
ASTM D 1050
What should you do when you are issued new rubber goods
Never assume the equipment is in good condition. Check for test dates, which should be printed on the equipment, and do a visual inspection
Rubber gloves should be store in……
canvas bag with the cuff facing down
Rubber blankets are used for what…..
to cover odd shape Equpment and conductor
What are the diameter of the line hoses
1 to 1 1/2 inches
Where should be store at
in canvas bags or sealed containers
what type of polyethene sizes
there are various sizes such as one that can wrap around a pole and those that can wrap around a conductor 2 inches of diameter also, they are constructed for cross arms single and doubles, and insulator pins
what are rubber hood purpose
are designed for rubber line to be inserted into them
note it also covers pin, post type insulator
What ither names for ozone
corona cutting, ozone deterioration, oxidation and cracking
Where is ozone present and how its made
its in the air. created by sunlgiht from oxygen in the air.
it at low concentration but high enough to damage rubber
What other things can create ozone
Electricity in moderate to high discharge such as arcs, sparks form machinery and lightning also create ozone
electrical corona also produces high concentration of ozone
what is the definition of corona
a luminous discharge due to ionization of air surrounding an electrical conductor with a voltage gradient exceeding a certain critical value
corona occurs where
im most high voltage and as little voltage as 2400 volts
The action between rubber and ozone is consider what?
rubber resistance to ozone
what is the minimal elongation strain a rubber can have before corona damage
2%
The maximum rate of damage that can rubber get from ozone happens when
When the rubber is elongated 10% to 20%
When does elongation or strain happens on the rubber
Any time is distorted from it from its natural shape
How to tell the rubber has ozone damage
when the surface area covered with many fine lines or cuts, usually perpendicular to the strain, which often connect into distinct cuts. These become more apparent when the rubber is rolled or stressed for inspection to open up the cuts.
What are the 2 causes that make ozone cutting
misapplication and improper storage
note also when ozone is present
Where can ozone be found
It can be found in close dark room with no vitiation. Thats its lowest form
It highest form is in sunlight and around machinery
What should you do to take care of rubber blankets
Blankets should be laid flat while in long-term storage. They may be rolled and kept in PVC tubes or canvas bags, but never folded when on the trucks. Crease marks caused by lasting folds, sharp bends, or continued distortion set up a stressed condition and invite corona damage.
What should you do to take care of rubber line hoses
Line hoses should not be bent to fit into small compartments.
What should you do to take care of rubber sleeves
Rubber sleeves should be rolled lengthwise while stored in trucks and kept in canvas bags.
What should you do to take care of rubber gloves
Do not store or use rubber gloves turned inside out. The reversal from the original set of the rubber sets up a sufficient amount of strain that can induce severe cracking, especially under the influence of ultraviolet (sunlight) or ozone (electrical apparatus).
Do not store rubber gloves or other protective equipment in substations or other locations where there is a likelihood of corona or a spark discharge. A very small concentration of ozone causes rapid oxidation of rubber.
What should you do with leather protective gloves
Leather protector gloves should be replaced if they no longer give adequate protection to rubber gloves. Oil-soaked protector gloves should not be used over rubber gloves; they should be replaced.
what are the enemies of rubber
Oil and grease are natural enemies of rubber. If exposed to either, rubber should be cleaned with hot, soapy water. After such an exposure, the gloves should be electrically tested.
where should you keep glove and sleeve
Gloves and sleeves should be protected from injury by keeping them in glove bags or sleeve bags when not in actual use.
What should line hose and blanket never be use for
Line hose or blankets should never be used to insulate one conductor from another. The rubber goods are designed and intended for personal protection only. The combination of mechanical strain and voltage can injure the rubber and make them unsafe for further use.
Why doubling rubber is not smart
Doubling of rubber goods does not increase their insulating value. If a rubber blanket is good for 10,000 volts, two blankets stacked on top of each other still have an insulating value of 10,000 volts.
Metal dust do what to rubber
Metal dust as is created in truck tool bins from bolts, etc., will contaminate rubber goods. Rubber goods should not be carried in these bins unless they are protected from contamination by being stored in appropriate containers.
When does phase to phase exposure exist
whenever it is foreseeable that an employee, or the longest conductive object he or she may handle, can simultaneously breach the electrical components of the MADs of live parts energized at different phase potentials, taking into account such factors as: the nature of the work being performed, the physical configuration and spacing of the conductors, the proximity of grounded objects or other circuit conductors, the method of approach to the conductors, the size of the employee, the tools and equipment being used, and the length of the conductive object.
When does phase to ground exposure exist
whenever it is foreseeable that an employee, or the longest conductive object he or she may handle, can simultaneously breach the electrical component of the MAD of an energized conductor and a grounded surface.
How to determine MAD of phase to phase and phase to ground is by
subtract two feet from the value listed for the system voltage
What is the relation between MAD and Rubber
Rubber lets the person handle the energize component that Minimal approach distance doesn’t allowed until its cover and safe to handle
