Equipment & devices: Texas Journeyman Electrician Practice Questions

For a 120/240 V panelboard (150 V or less to ground) with exposed live parts on one side and no live or grounded parts on the other (Condition 1), what is the minimum depth of working space?

At 0-150 V to ground the minimum working-space depth is 3 ft for every condition.

What is the minimum width of the working space in front of electrical equipment?

The working space must be at least 30 in wide or as wide as the equipment, whichever is greater.

In general, the working space in front of service equipment and panelboards must have a clear height of at least:

The general minimum headroom is 6½ ft (or the height of the equipment, if taller).

Listed or labeled equipment must be installed and used:

Listed equipment is installed and used following the instructions that come with its listing or labeling.

In a dwelling living room, receptacles must be placed so that no point along the floor line of a wall is more than how far from a receptacle?

The general wall-receptacle rule: no point along the floor line more than 6 ft from a receptacle, so outlets are no more than 12 ft apart.

According to the NEC, how must listed or labeled equipment be installed and used?

Section 110.3(B) ties the installation of listed or labeled equipment to the instructions that come with the listing or labeling.

A knockout was removed from a panelboard but no raceway or cable was installed in it. According to the NEC, what must be done with the opening?

Under 110.12(A), unused openings other than those for mounting or drainage must be closed so the protection is substantially equivalent to the wall of the equipment.

Which method of fastening electrical equipment to a concrete wall does the NEC prohibit?

Section 110.13(A) requires equipment to be firmly secured and does not allow wooden plugs driven into holes in masonry, concrete, plaster or similar materials.

Two conductors need to land under one terminal screw of a device. When does the NEC allow this?

Section 110.14(A) permits terminals for more than one conductor only where the terminal is identified for that use.

For a 30-A circuit whose equipment terminals are not marked otherwise, conductor ampacity is generally based on which temperature column?

For circuits rated 100 A or less, or conductors 14 AWG through 1 AWG, 110.14(C)(1)(a) limits termination temperature to 60°C unless the equipment is listed and marked for a higher rating.

For a 200-A feeder with conductors larger than 1 AWG, termination temperature for ampacity purposes is generally limited to:

Section 110.14(C)(1)(b) applies the 75°C limit to circuits over 100 A or conductors larger than 1 AWG, unless equipment is listed and marked otherwise.

The installation instructions give a numeric tightening torque for a panelboard's lugs. Which of these is an approved means to tighten them to that value?

Since the 2020 edition, 110.14(D) requires an approved means, such as a torque tool or a shear bolt, to reach the tightening torque marked on equipment or given in its instructions. Tightening by feel or with an impact driver is not an approved means.

Which field-applied hazard warning label meets the NEC?

Section 110.21(B) requires field-applied hazard markings to warn effectively, be permanently affixed, be durable for the environment and not be handwritten (except variable information).

According to the NEC, what must be legibly marked on each disconnecting means, unless it is obvious from its location and arrangement?

Section 110.22(A) requires each disconnecting means to be marked to show its purpose, with a marking durable enough for the environment.

In other than dwelling units, what must be field marked on service equipment?

Section 110.24(A) requires service equipment in other than dwelling units to be field marked with the maximum available fault current and the date of the calculation.