IEC Conductors and Branch Circuits 3

Question 1

A multiwire branch circuit in a dwelling unit must have a means to simultaneously disconnect all ungrounded conductors. Which NEC section requires this?

Accepted Answer

210.4(B)

Answer

NEC Section 210.4(B) requires that each multiwire branch circuit in a dwelling unit be provided with a means to simultaneously disconnect all ungrounded conductors at the panelboard.

Question 2

What factor primarily determines the voltage drop on a branch circuit conductor run?

Accepted Answer

Conductor length and load current

Answer

Voltage drop is primarily a function of conductor resistance (related to length and wire gauge) multiplied by the load current.

Question 3

Under NEC Article 210, which branch circuit type is required for bathroom receptacles in a dwelling unit?

Accepted Answer

20-ampere circuit dedicated to bathroom receptacles

Answer

NEC Section 210.11(C)(3) requires at least one 20-ampere branch circuit dedicated to bathroom receptacles in dwelling units.

Question 4

When must tap conductors be protected by an overcurrent device at the point where they receive their supply?

Accepted Answer

Exceptions in NEC 240.21 allow unprotected taps under specific length and ampacity conditions

Answer

NEC Section 240.21 provides tap conductor exceptions that allow conductors to be run without overcurrent protection at the source under defined length and ampacity rules.

Question 5

Which conductor insulation temperature rating allows the highest ampacity for a given AWG size in a dry location?

Accepted Answer

90°C (THHN/THWN-2)

Answer

A 90°C-rated insulation (such as THHN or THWN-2 in dry locations) permits the highest ampacity table values for a given conductor size.

IEC - Independent Electrical Contractors Practice Test

IEC - Independent Electrical Contractors Practice Test

IEC Conductors and Branch Circuits 3