type of ground connectors Flashcards
After igniting the powder in an exothermic mold, one should wait approximately ? for the weld to cool and solidify before opening the mold.
30 seconds
The extreme temperatures of exothermic reactions produce temperatures of ? in the crucible of the mold.
4,000 F
Of the most commonly used connections, the ? type presents the greatest hazards to the substation worker during installation.
cadweld
When making connections in an existing substation, a person can be subject to electric shock when bridging across a point in the grid. Which of the following is the proper safety procedure?
use temp jumper before making the permanent connections
Which of these statements regarding wedge type connections is true?
there are no temp or weather restrictions
IEEE 80 rates the maximum allowable temperature limits for welded connections on ground grids only.
false
A bonding of the conductors at a molecular level is the result of a(n) ? type connection.
cadweld
After the area to be connected is cleaned, the application of conductive grease is necessary if ? connectors are used. This type of connector is normally shipped dry.
c-clamp
When engineers select the type of connectors to be used, they take into account the maximum fault current that will be imposed on the connectors and the ? of the connectors.
temp limits
The presence of ? in an exothermic mold will result in an explosion when the metal powder is ignited.
water
The exothermic welding process uses powdered metals such as copper oxide and ? to produce the chemical reactions necessary.
aluminum
A wedge connector produces a molecular bond with a current-carrying capability equal to or greater than that of the conductors being joined.
false
A substation ground grid is typically constructed ? below the finish grade.
12’’ to 18’’
Graphite is used to make an exothermic mold.
true
Carbon traces found when inspecting exothermic connections is evidence of ?
oil on the cable strands
