TL;DR
Master conductor sizing, ampacity calculations, and derating factors per NEC tables. Wire sizing is fundamental to electrical safety and one of the most tested exam topics.
Free NM Cable (Art. 334) Practice Questions
Journeyman Electrician License Exam · Wiring Methods & Materials
This module covers NM Cable (Art. 334) as part of the Wiring Methods & Materials section, testing your understanding of core concepts and their practical application.
| Exam | Journeyman Electrician License Exam |
| Pass Rate | 55% |
| Duration | 240 minutes |
| Module | NM Cable (Art. 334) |
Why NM Cable (Art. 334) matters
NM Cable (Art. 334) is a commonly tested topic on the Journeyman Electrician License Exam because it covers fundamental knowledge required for competent professional practice.
Sample Practice Questions (5)
1. Per NEC 334.80, how many 14/2 NM cables can be bundled together through a bored hole in a stud before ampacity adjustment (derating) is required?
- More than 2 cables containing 2 or more current-carrying conductors passing through the same opening require adjustment
- Up to 10 cables before derating is needed
- Only 1 cable per hole is allowed
- Ampacity adjustment is never required for NM cable through framing
2. Per NEC 334.40, where NM cable enters a single-gang box that does not contain a cable clamp, the cable sheath must extend into the box at least how far?
- 1/4 inch past the cable knockout or opening
- 1/2 inch past the cable knockout
- 1 inch past the cable knockout
- No sheath extension is required
3. A contractor wants to use NM cable in a multifamily apartment building. Per NEC 334.10(3), NM cable is permitted in multifamily dwellings only if the building is of what construction type and height?
- Types III, IV, and V construction, not exceeding three floors above grade
- Any construction type, not exceeding five floors
- Type I and II construction, any height
- Wood frame only, not exceeding two floors
Want more practice like this?
Start practicing free →4. Per NEC 334.12, NM cable shall NOT be used in which of the following?
- Commercial garages as defined in Article 511
- One-family dwelling basements
- Detached garages of a single-family home
- Attics of two-family dwellings
5. Where NM cable is run through holes in studs or joists, the cable is considered supported and secured. According to NEC 334.30, what is the exception regarding securing flat cables?
- NM cable run through bored holes in framing members is considered supported and does not need to be stapled between holes
- NM cable must still be stapled every 2 feet within framing
- NM cable through holes must also be secured with cable ties
- Only MC cable is exempt from securing when run through holes
Ready to practice for the Journeyman Electrician License Exam?
Adaptive practice powered by Item Response Theory targets your weak areas. Start with 3 free sessions.
Start free practice →