E2 Working Space and Clearances 3

Question 1

What is the maximum voltage allowed to still qualify for the 3-foot minimum working space depth under Condition 1 per NEC 110.26(A)(1)?

Accepted Answer

600V nominal or less

Answer

NEC 110.26(A)(1) Table applies to equipment operating at 600V nominal or less, with Condition 1 requiring a minimum 3-foot working space depth for this voltage range.

Question 2

A technician needs to work on a 480V panelboard where one side has an exposed energized bus and the opposite side has a concrete block (grounded) wall. Which working space Condition applies?

Accepted Answer

Condition 2

Answer

Condition 2 applies when there are exposed live parts on one side and grounded parts (such as a concrete/masonry wall) on the other side.

Question 3

According to NEC 110.26(C)(1), how many means of egress are required for a room with electrical equipment rated 1200A or more and over 6 feet wide when the room exceeds 50 feet in length?

Accepted Answer

Two entrances located at each end of the working space

Answer

NEC 110.26(C)(1) Exception requires two entrances located at each end of the working space for rooms exceeding 50 feet in length with large equipment.

Question 4

Pipes, ducts, or equipment foreign to electrical installations are permitted in dedicated electrical space under which condition?

Accepted Answer

Never — NEC strictly prohibits all foreign systems

Answer

NEC 110.26(F)(1)(b) states that the dedicated space shall not be used for piping, ducts, leak protection apparatus, or any equipment foreign to the electrical installation.

Question 5

What is the required working space depth for 480V equipment (Condition 2) per NEC 110.26(A)(1)?

Accepted Answer

4 feet

Answer

Per NEC 110.26(A)(1) Table, for voltages from 151V to 600V under Condition 2, the minimum working space depth is 3.5 feet.

(E2) E2 Commercial Electrical Inspector Practice Test

(E2) E2 Commercial Electrical Inspector Practice Test

E2 Working Space and Clearances 3