Test Your Code IQ — March 2026

Courtesy of www.MikeHolt.com.

All questions and answers are based on the 2023 NEC.

Q1: In a dwelling unit, dimmer control of lighting outlets for interior stairways installed in accordance with Sec. 210.70(A)(2)(3) shall not be permitted unless the listed control devices can provide dimming control _____ at each control location for the interior stairway illumination.

a) for illumination

b) for emergency lighting

c) to maximum brightness

d) for effective lighting

Q2: The grounded circuit conductor for the controlled lighting circuit shall be installed at the location where switches control lighting loads that are supplied by a grounded general-purpose branch circuit serving _____.

a) habitable rooms or occupiable spaces

b) attics

c) crawlspaces

d) basements

Q3: Transformers, other than Class 2 or Class 3 transformers, shall have a disconnecting means located either in sight of the transformer or in a remote location. Where located in a remote location, the disconnecting means shall be lockable open in accordance with Sec. 110.25, and _____.

a) its location shall be field marked on the transformer

b) accessible only to qualified persons

c) placed in supervisory locations

d) none of these

Q4: A(An) _____ or larger grounding electrode conductor exposed to physical damage shall be protected in rigid metal conduit, IMC, Schedule 80 PVC conduit, reinforced thermosetting resin conduit XW (RTRC-XW), EMT, or cable armor.

a) 10 AWG

b) 8 AWG

c) 6 AWG

d) 4 AWG

Q5: The minimum thickness of sealing compound in Class I locations shall not be less than the trade size of the conduit or sealing fitting and, in no case, shall the thickness of the compound be less than _____.

a) 1⁄8 in.

b) ¼ in.

c) 3⁄8 in.

d) 5⁄8 in.

Q6: Expansion, expansion-deflection, or deflection fittings and telescoping sections of metal raceways shall be made _____ continuous by equipment bonding jumpers or other means. 

a) physically

b) mechanically

c) electrically

d) directly

Answers:

Q1: c) to maximum brightness

Section 210.70(A)(2)(4) states, "Dimmer control of lighting outlets installed in accordance with Sec. 210.70(A)(2)(3) shall not be permitted unless the listed control devices can provide dimming control to maximum brightness at each control location for the interior stairway illumination."

Q2: a) habitable rooms or occupiable spaces

Per Sec. 404.2(C): "The grounded circuit conductor for the controlled lighting circuit shall be installed at the location where switches control lighting loads that are supplied by a grounded general-purpose branch circuit serving bathrooms, hallways, stairways, and habitable rooms or occupiable spaces."

Q3: a) its location shall be field marked on the transformer

According to Sec. 450.14, "Transformers, other than Class 2 or Class 3 transformers, shall have a disconnecting means located either in sight of the transformer or in a remote location. Where located in a remote location, the disconnecting means shall be lockable open in accordance with Sec. 110.25, and its location shall be field marked on the transformer."

Q4: c) 6 AWG

Per Sec. 250.64(B)(2): A 6 AWG or larger grounding electrode conductor exposed to physical damage shall be protected in rigid metal conduit, IMC, Schedule 80 PVC conduit, reinforced thermosetting resin conduit XW (RTRC-XW), EMT, or cable armor.

Q5: d) 5⁄8 in.

Section 501.15(C)(3) confirms, "in no case shall the thickness of the compound be less than 5⁄8 in."

Q6: c) electrically

According to Sec. 250.98, "Expansion, expansion-deflection, or deflection fittings and telescoping sections of metal raceways shall be made electrically continuous by equipment bonding jumpers or other means."

These materials are provided by Mike Holt Enterprises in Leesburg, Fla. To view Code training materials offered by this company, visit www.mikeholt.com/code.