Exam 19: Equipment and Conductor Short-Circuit

Copper conductors can withstand one ampere (rms current)for ____ seconds for every 42.25 circular mils (cm)of cross-sectional area.

A bare conductor can withstand higher levels of current than an insulated conductor of the same cross-sectional area. Do not exceed one ampere (rms current)for five seconds for every ____ circular mils of cross-sectional area of the conductor.

The term short-circuit current rating is synonymous with the term ____ rating.

Define an effective ground-fault current path.

You can determine a conductor's short-time withstand rating using charts published by the ____.

The interrupting rating is the ____ at rated voltage that a device is intended to interrupt under standard test conditions.

A 75°C thermoplastic insulated Type THWN copper conductor can withstand 4200 amperes for one cycle. What is the I ² t let-through value for a noncurrent-limiting circuit breaker that takes one cycle to open? The available fault current is 40,000 amperes.

In a short circuit, the conductors ____.

In an overloaded circuit, the conductors ____.

A 10 AWG copper conductor's withstand rating is ____ ampere squared seconds.

What impedance remains in the circuit under short-circuit or ground-fault conditions?

What is the conservative approach to conductor withstand ratings?

The value of energy (heat)generated during a fault varies as the ____ multiplied by the time (duration of fault)in seconds.

The amount of heat generated in a conductor or other electrical equipment depends on how much current flows and ____.

____ forces acting upon electrical equipment (busbars, contacts, conductors, and so on)are proportional to the square of the PEAK current.

What damage can occur to conductors under fault conditions?

What are the requirements for bonding as they relate to electrical continuity?