PEC 4

Open conductors passing over residential driveways and those commercial areas not subject to truck traffic where the voltage exceeds 300 V to ground shall have vertical clearance of ______.

• 3,700 mm

• 4,600 mm

• 3,100 mm

• 5,500 mm

What is the radius of a solid round conductor, which is the nearest equivalent of a stranded conductor whose total area is exactly 8.0 mm²?

• 1.597 mm

• 1.596 mm

• 3.191 mm

• 3.192 mm

Where galvanized steel conduit is used, the primary purpose of galvanizing in which one of the following?

• it provides good electrical contract for grounding

• it increase the mechanical strength

• it provides good surface for printing

• it retards rusting

Equipment to be installed shall be fully specified in the name plate EXCEPT which of the following considered optional?

• power and speed rating

• voltage, current, frequency

• name of manufacturer

• date manufactured

A three-phase general purpose squirrel cage motor draws a full load current of 40 A. What is the maximum size of time delay fuses that may be used for short circuit protection?

• 120 A

• 80 A

• 40 A

• 100 A

Busways shall be permitted to be installed behind panels if means of access are provided and if the conditions below are met. One of them is NOT valid. Which one is this?

• No overcurrent devices are installed on the busway other than for an individual fixture

• The busway is so installed that the joints between sections and fitting are accessible for maintenance purpose

• The busway is open and of ventilator type

• The space behind the panels is not for air handling purposes

When alternating current flows through a conductor, there is an inductive action that causes the current in the conductor to be forced toward the outer surface. The current is greater at the surface that at the center of the conductor, this, _______ will cause the resistance in the conductor to increase due to the increased heating of the conductor

• superconductive effect

• capacitive effect

• outer effect

• skin effect

The _______ shall not be less than the continuous load plus 125% of the continuous load.

• conductor size

• branch circuit rating

• non continuous load

• continuous load

What is the maximum rating of a molded case circuit breaker to protect a 10 hp squirrel cage induction motor rated at 230 volts, 3-phase, 60 Hz with a full load rating of 28 A?

• 30 A

• 50 A

• 70 A

• 100 A

Any motor application shall be considered as _____ duty unless the nature of the apparatus it drives is such that the motor will not operate continuously with load under any condition of use.

• short time

• periodic

• continuous

• varying