Most cable questions are really questions about the environment

Damp, wet, buried, exposed to damage, or inside a fire-rated assembly. Name the condition and the answer narrows to one or two.

Sort by environment first

A cable question gives you a location and asks whether a method is permitted. So the first move is to classify the location, not to recall the cable.

Dry, damp and wet are defined terms with specific meanings, and a location that feels damp in ordinary English may be classified wet in the code.

Get the classification right and most of these questions answer themselves, because each article states plainly which classifications it permits.

The common types and their character

• Nonmetallic-sheathed cable. Cheap, common in dwellings, and restricted by building type and by exposure. Its article carries a permitted-uses list and a not-permitted list, and the second is the one people skip.
• Metal-clad cable. Interlocked armor, broader permitted uses, and whether the armor serves as an equipment grounding path depends on the type.
• Armoured cable. Similar appearance to metal-clad and different rules, which is exactly why questions pair them.
• Underground feeder cable. Rated for direct burial, which most of the others are not.
• Service entrance cable. Two styles with different permitted uses.

Metal-clad and armoured being visually similar and legally different is the single most reliable distractor pair in this topic.

The Texas amendment worth checking

State adoptions sometimes amend which cable types are permitted in which occupancies, and those amendments do not appear in national training material.

Before relying on a national summary about nonmetallic-sheathed cable in particular, check the state-adopted version, because that is the code the exam tests.

What a question is actually asking

• Names a location: classification question, then the permitted-uses list.
• Names two similar cables: it wants the distinction between them.
• Mentions burial: it wants to know which are listed for direct burial.
• Mentions a raceway containing a cable: it may be a fill question wearing a costume.

What this page cites

• NEC 334.10 Nonmetallic-sheathed cable, uses permitted.
• NEC 334.12 Uses not permitted, the list people skip.
• NEC 330.10 Metal-clad cable, uses permitted.
• NEC 100 Definitions of dry, damp and wet locations.