CEP Installation & Maintenance Practices 4

Question 1

What is the maximum voltage drop recommended by NEC 210.19(A) Informational Note for branch circuits to minimize energy waste?

Accepted Answer

3% for branch circuits

Answer

NEC 210.19(A) Informational Note No. 4 recommends a maximum 3% voltage drop for branch circuits, with 5% total for feeders and branch circuits combined.

Question 2

When installing liquidtight flexible metal conduit (LFMC) in a wet location, what additional fitting requirement applies?

Accepted Answer

Only listed liquidtight fittings rated for wet locations are permitted

Answer

NEC 350.42 requires listed fittings specifically designed for use with LFMC, and when used in wet locations, those fittings must be listed for wet locations.

Question 3

A maintenance worker discovers that the equipment grounding conductor (EGC) in a 20A, 120V circuit has been disconnected at the receptacle. What is the immediate hazard?

Accepted Answer

Fault current may energize metal enclosures, creating a shock hazard

Answer

Without the EGC, a fault in the equipment will energize the metal casing, creating a lethal shock hazard since there is no low-impedance return path to trip the breaker.

Question 4

What does NEC Article 410 require regarding the clearance between a recessed luminaire and thermal insulation?

Accepted Answer

At least 3 inches of clearance unless the luminaire is IC-rated

Answer

NEC 410.116(B) requires at least 3 inches of clearance between recessed luminaires and thermal insulation unless the luminaire is listed and marked as suitable for direct contact with insulation (IC-rated).

Question 5

When testing a newly installed grounding electrode system, what is the maximum acceptable ground resistance for a single electrode per NEC 250.56?

Accepted Answer

25 ohms

Answer

NEC 250.56 states that if a single ground rod, pipe, or plate electrode has a resistance to ground exceeding 25 ohms, a supplemental electrode must be added.

(CEP) Certified Electrical Professional Practice Test

(CEP) Certified Electrical Professional Practice Test

CEP Installation & Maintenance Practices 4