Wiring Methods & Materials — NASCLA Electrical Practice Questions

16 questions · 16% of the NASCLA Electrical exam

Worked questions

1. On a community-center project during plan review, a long exposed PVC raceway crosses a large temperature range; what should the installer evaluate?

AFilling joints with concrete
BOnly voltage drop
CRemoval of supports
Thermal expansion fittings

Why D is correct

PVC changes length significantly with temperature; accommodating movement prevents buckling and stress at enclosures. The best answer is therefore “Thermal expansion and the need for listed expansion fittings.” The other choices either address a different system, rely on an unsafe shortcut, or make a conclusion not supported by the stated facts.

2. On a single-family remodel during rough-in, a raceway penetration is made through a rated wall; how should it be closed?

ABy leaving an air gap
A matching firestop system
CWith ordinary painter's caulk
DWith loose insulation

Why B is correct

Rated assemblies depend on tested penetration details; generic filler does not demonstrate equivalent fire resistance. The best answer is therefore “With an approved firestop system installed for the specific assembly and penetration.” The other choices either address a different system, rely on an unsafe shortcut, or make a conclusion not supported by the stated facts.

3. A box-fill worksheet supplies these allowances: conductors 12.0 in³, equipment grounding group 2.0 in³, internal clamps 2.0 in³ and device yoke 4.0 in³. What minimum volume follows from these stated allowances?

A12.0 in³
20.0 in³
C16.0 in³
D18.0 in³

Where to look it up

Explicit exercise assumptions; not a universal code requirement.

Why B is correct

Sum every supplied allowance: 12 + 2 + 2 + 4 = 20 in³. The exercise checks aggregation, not the code treatment of an unspecified conductor size, clamp arrangement or NEC edition.

4. A metallic conduit run crosses a structural joint designed for movement. Which approach addresses the movement and grounding path?

ARigidly bridge the joint with an ordinary coupling regardless of movement.
BLeave the conduit disconnected across the joint.
CAssume all expansion fittings have identical internal bonding provisions.
Select a suitable expansion/deflection fitting and maintain grounding continuity according to its instructions.

Where to look it up

https://www.eaton.com/content/dam/eaton/products/conduit-cable-and-wire-management/crouse-hinds/literature/crouse-hinds-conduit-expansion-deflection-brochure.pdf

Why D is correct

Eaton describes movement fittings for structural joints. Its product variants have different bonding provisions, so verify the selected fitting rather than universally requiring or omitting an external jumper.

12 more in the bank

Answers and explanations for these are in the app.

Using the raceway schedule shown, what information controls whether the added conductors fit?
The route diagram shows four 90-degree bends between pull points. What should be added or changed?
On a hotel renovation during plan review, raceway outdoors contains insulated conductors marked only for dry locations; what is the issue?
On a tenant improvement during rough-in, cable is draped across ceiling-grid wires that are not identified for electrical support; what is required?
On a restaurant build-out during rough-in, metal raceway is planned in a highly corrosive process area; what must be considered?
On a small hospital renovation during rough-in, a conductor splice is proposed inside a raceway body not marked with sufficient volume; what is the correct approach?
What information controls pull-box dimensions for large conductors?
A cable is proposed in tray but is not identified for that use. Is it acceptable?
A metal raceway fitting is not identified for grounding continuity. What is required?
A raceway route is made shallower than planned by final grading. What should be checked?
Long vertical conductors place excessive weight on terminations. What is required?
Flexible cord is routed through a wall as permanent branch wiring. What is the issue?

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