Electric Signs practice questions

Correct: C — The disconnect must be lockable in the open position and the sign must carry a marking showing the disconnect's location

Under 600.6(A)(2), when the disconnect is out of the line of sight from any section able to be energized, it must be lockable per 110.25 and the sign must carry a permanent field-applied marking identifying the disconnect's location. Relocating to the point of entry or adding a second disconnect are not the code's remedy — marking and lockability are.

Correct: C — One

Per 600.32(A)(2), conduit or tubing for neon secondary circuits over 1000V shall contain only one conductor. This is a special rule distinct from ordinary conduit fill tables that allow multiple conductors, and it applies regardless of conductor size or function.

Correct: C — No, metal building parts cannot be used as the bonding means for sign metal parts

600.7(B)(3) specifically prohibits using metal building parts as a bonding means for sign or outline lighting metal parts or equipment, regardless of the girt's continuity or its own bonding status. A dedicated bonding conductor per 600.7(B)(1) and (B)(7) is required instead.

Correct: B — 30 amperes

Per 600.5(C)(1), branch circuits supplying neon tubing installations shall not be rated in excess of 30 amperes. The 20 A figure is the limit for all other signs and outline lighting systems under 600.5(C)(2), not neon.

Correct: B — No, metal parts of a building are not permitted as an equipment grounding conductor or secondary return conductor

600.7(A)(5) specifically prohibits using metal building parts as a secondary return conductor or equipment grounding conductor for signs. The sign must instead connect to a proper 250.118 equipment grounding conductor per 600.7(A)(1); building steel continuity doesn't change this, and the cord-and-plug exception in 600.7(A)(1) is unrelated to this rule.

Correct: D — 4.3 m (14 ft)

Per 600.9(A), sign or outline lighting equipment must be at least 4.3 m (14 ft) above vehicle-accessible areas unless protected from physical damage. 10 ft and 12 ft are below that threshold and would require added protection; 18 ft exceeds the requirement unnecessarily.

Correct: A — A sign, an outline lighting system enclosure, a suitable box, a conduit body, or a panelboard

600.5(D)(1) lists five acceptable termination points: a sign, an outline lighting system enclosure, a suitable box, a conduit body, or a panelboard. Limiting termination to only the sign itself, to any nearby weatherproof box, or excluding the sign enclosure all narrow the rule incorrectly.

Correct: B — CL2R

Per 600.33(A)(2), vertical shafts and risers require CL2R or CL3R. CL2P is the plenum/environmental air space designation, not the riser designation, so it doesn't satisfy this specific location requirement. General-use CL2 cable is for 600.33(A)(1) locations and is not automatically suitable for a riser unless it carries the riser rating.

Correct: D — The connection must be enclosed in a listed box

600.33(B)(2) requires connections made in a wall to be enclosed in a listed box, in addition to using listed insulating devices and remaining accessible after installation. Tape alone isn't sufficient inside a wall, relocating outside the wall isn't required by this rule, and burying an inaccessible splice violates the accessibility requirement.

Correct: C — 600.24(B)

600.24(B) is the specific rule requiring metal parts of a Class 2 power supply/source to be connected to the equipment grounding conductor. 600.24(A) only covers listing requirements, and 600.23(B) governs ground-fault protection for Class 1 transformer/electronic power supply secondary circuits, not Class 2 bonding.

Correct: D — In dry locations only

Per 600.42(H)(2), enclosures installed in damp and wet locations must be specifically listed, labeled, and identified for those locations. A dry-location-only listing does not extend to damp or wet use, and adding a listed cap under 600.42(G) addresses sealing a penetration, not the enclosure's location rating.

Correct: B — 38 mm (1 1/2 in.)

600.32(E) requires secondary conductors to be separated from each other and from all objects other than insulators or neon tubing by not less than 38 mm. The 65 mm figure is a different requirement — that's the minimum insulation extension beyond a raceway under 600.32(G) — and spacing is required regardless of insulator use.

Correct: B — 600.32(B)

600.32(B) is the section titled Insulation and Size — it lists the 5, 10, or 15 kV ratings, the 18 AWG minimum, and the 105°C minimum temperature rating for GTO cable. 600.32(A)(3) instead covers size requirements for the general secondary-circuit wiring methods of 600.32(A), not the GTO cable's own insulation/size spec, and 600.32(C) and 600.32(E) address installation protection and spacing, not conductor rating or size.

Correct: C — The maximum allowable lamp wattage per lampholder

600.4(C) requires the marking to state the maximum allowable lamp wattage per lampholder. A listing number, install date, and circuit voltage are not what this specific marking requirement calls for.

Correct: D — Any wiring method included in Chapter 3 that is suitable for the conditions

600.31(A) permits any Chapter 3 wiring method suitable for the conditions of installation — there's no restriction to a special neon-only method, open wiring, or a single conduit type. Those more restrictive options are confusions with higher-voltage neon secondary rules elsewhere in Article 600.

Correct: B — 6 mm (1/4 in.)

600.41(C) sets the minimum air space at 6 mm (1/4 in.) between the tubing and any nearby surface, excluding the support itself. The larger spacings are common clearance figures used elsewhere in the Code but aren't the neon tubing spacing value.

Correct: A — Integral to the attachment plug, or in the cord within 300 mm (12 in.) of the plug

600.10(C)(2) requires the manufacturer-provided GFCI to be integral to the attachment plug or located in the power-supply cord within 300 mm (12 in.) of the plug. A GFCI elsewhere on the circuit, at the disconnect, or at the panelboard does not meet this specific placement requirement, even though 210.8 GFCI protection may also apply elsewhere.

Correct: D — A permanent walkway at least 300 mm (12 in.) wide extending to the component

600.21(E) requires a permanent walkway at least 300 mm (12 in.) wide extending from the point of entry to each component. The passageway dimensions are reversed in the second distractor — it's 900 mm (3 ft) high by 600 mm (2 ft) wide, not the other way around. Only one lighting outlet is required, not two, and the point of control must be at the usual point of entry, not only at the equipment.

Correct: A — The accessibility requirement of 600.21(A)

600.21(A) requires ballasts, transformers, electronic power supplies, and Class 2 power sources to be located where accessible and securely fastened in place. Burying one behind fixed panels blocks access, which is separate from the enclosure rule in 600.21, the proximity rule in 600.21(B), or the wet-location rule in 600.21(C), none of which are at issue here.

Correct: D — It must be secured at intervals not exceeding 0.91 m (3 ft)

600.34(B)(3) requires external PV sign wiring to be as short as possible and secured at intervals not exceeding 0.91 m (3 ft). There's no rigid-conduit mandate in this section, the wiring must closely follow the sign body per 600.34(B)(2) rather than being routed away from it, and 1.5 m (5 ft) is not the specified interval.

Correct: A — Article 690, Part V

600.34(D) requires PV sign grounding to comply with Article 690, Part V, in addition to 600.7. Article 690, Part III covers disconnecting means, not grounding, and is the cross-reference used for 600.34(E) instead. Skipping the Article 690 reference and relying on 600.7 alone would miss the PV-specific grounding provisions.

Correct: D — It must still be inspected for damage even though it wasn't replaced

600.35(B) requires all parts not replaced by the kit to be inspected for damage, with no exception based on the kit's listing scope, the sign's location rating, or the age of the part.

Correct: A — 600.32

Per 600.12(B), neon secondary circuit wiring over 1000 volts must comply with 600.32. The 600.31 path applies only at 1000 volts or less under 600.12(A). 600.24 and 600.33 apply to Class 2 output systems under 600.12(C), not to a 1200-volt neon secondary.

Correct: C — The equipment grounding conductor of the branch circuit for the fountain's recirculating system

600.7(B)(8) requires bonding to the equipment grounding conductor of the branch circuit that feeds the fountain recirculating system. A separate ground rod, the neutral conductor, and an unrelated receptacle's equipment grounding conductor are not acceptable bonding points.