Conduit & Raceway Systems Flashcards

When conduit penetrates a fire-rated wall or floor assembly, the NEC and building codes require:

Answer: An approved firestop system or fire-rated sealant to restore the fire rating

Any penetration through a fire-rated assembly must be sealed with a listed firestop system to restore the fire resistance rating and prevent the spread of fire and smoke through the opening.

The NEC requires conduit ends to be reamed or otherwise finished after cutting in order to:

Answer: Remove sharp edges that could damage conductor insulation during pulling

Reaming removes burrs and sharp edges left by cutting, which could nick or damage the insulation of conductors as they are pulled through the conduit.

When PVC conduit is installed in a location subject to physical damage, the NEC requires using:

Answer: Schedule 80 PVC, which has a thicker wall for greater impact resistance

Schedule 80 PVC has a significantly thicker wall than Schedule 40 and is listed for use where subject to physical damage, providing greater resistance to impact.

A wireway differs from conduit in that it:

Answer: Features a hinged or removable cover that provides access to conductors at any point

A wireway (also called a lay-in duct or trough) has a removable cover along its entire length, allowing conductors to be placed and accessed without pulling through a closed raceway.

Flexible Metal Conduit (FMC) may serve as the equipment grounding conductor (EGC) without a separate ground wire only when:

Answer: The circuit is protected at 20 amperes or less and the FMC length does not exceed 6 feet

Per NEC 348.60, FMC may serve as the EGC when the circuit overcurrent protection does not exceed 20 amperes and the total length of FMC in the ground return path does not exceed 6 feet.

Cable tray systems installed in industrial facilities may contain:

Answer: Power and communication cables provided they are separated in accordance with NEC Article 392

NEC Article 392 permits cable tray to contain power, control, signal, and communication cables, but requires separation between power and communication cables to prevent interference and meet safety requirements.

When conduit is installed in a straight, horizontal run, the NEC requires expansion fittings to be used when:

Answer: The conduit crosses a building expansion joint or when thermal expansion may cause excessive stress

Expansion fittings are required where conduit crosses structural expansion joints and where the expected thermal expansion (especially in PVC conduit) would be sufficient to cause mechanical damage to the raceway or its supports.