18.2 Places of Assembly, Carnivals & Fairs, and Temporary Installations (Articles 518, 525 & 590)
Key Takeaways
Article 518 applies to buildings or portions of buildings designed or intended for the gathering of 100 or more persons for purposes such as deliberation, worship, entertainment, eating, drinking, or awaiting transportation.
Amusement rides and attractions must be at least 15 ft in any direction from overhead conductors of 600 V or less, except the conductors supplying the ride (Article 525).
Temporary electrical power for holiday decorative lighting is limited to 90 days, and temporary wiring must be removed immediately when construction or the purpose for which it was installed is complete (590.3).
All 125 V, single-phase, 15-, 20-, and 30-ampere receptacle outlets that are not part of the permanent building wiring and are used by personnel during construction must have GFCI protection (590.6(A)).
On construction sites, receptacles may not be installed on branch circuits that supply temporary lighting (590.4(D)).
Places of assembly (Article 518)
Article 518 covers buildings or portions of buildings designed or intended for 100 or more persons: auditoriums, conference rooms, churches, restaurants, dance halls, gymnasiums, bowling alleys, museums, places of awaiting transportation, and similar. Theaters with stages are covered by Article 520.
| Rule | Requirement |
|---|---|
| General wiring methods (518.4(A)) | Metal raceways, flexible metal raceways, nonmetallic raceways encased in at least 2 in. of concrete, Type MI, MC, or AC cable containing an insulated EGC sized from Table 250.122 |
| Nonrated construction (518.4(B)) | Where the building or portion is not required by the building code to be of fire-rated construction, NM cable, AC cable, ENT, and PVC or RTRC conduit are also permitted |
| Spaces with finish ratings (518.4(C)) | ENT and PVC or RTRC may be installed in concealed spaces of walls, floors, and ceilings behind a thermal barrier with at least a 15-minute finish rating |
| Temporary wiring (518.3) | Temporary wiring for exhibition booths may follow Article 590, with flexible cords and cables approved for hard or extra-hard usage |
| Portable switchboards and stage equipment | Article 520 applies |
Minnesota's State Building Code determines whether a portion of a building must be of fire-rated construction, which in turn decides whether NM cable may be used.
Carnivals, circuses, fairs, and similar events (Article 525)
The 2026 NEC restructured and rewrote Article 525 for clarity, separating disconnecting means rules for moving and nonmoving equipment and adding rules for portable and vehicle- or trailer-mounted generators.
| Rule | Requirement |
|---|---|
| Overhead conductor clearances | Vertical clearances to the public follow 225.18; amusement rides and attractions must be maintained at least 15 ft in any direction from overhead conductors operating at 600 V or less, except the conductors that supply the ride |
| Services and power sources | Service equipment may not be installed in a location accessible to unqualified persons unless lockable; generators and other sources must be protected from public contact |
| Wiring methods | Flexible cords and cables must be listed for extra-hard usage, and where used outdoors, also listed for wet locations and sunlight resistant |
| Protection | Cords and cables accessible to the public must be arranged to minimize tripping and covered with nonconductive matting where run across walkways |
| Boxes and fittings | A box or fitting is required at each connection point, outlet, switch point, or junction |
| GFCI protection | 125 V, single-phase, 15- and 20-ampere nonlocking receptacles used for disassembly and reassembly, or readily accessible to the public, must be GFCI protected; egress lighting may not be GFCI protected |
| Grounding and bonding | All equipment requiring grounding is connected to an EGC; the 2026 NEC adds an exception for portable inverter generators manufactured with no grounded-conductor connection to the frame |
Temporary installations (Article 590)
Time constraints (590.3)
| Use | Time limit |
|---|---|
| Construction, remodeling, maintenance, repair, or demolition | For the duration of the work |
| Holiday decorative lighting and similar purposes | Not more than 90 days |
| Emergencies and tests | For the duration of the emergency or test, such as developmental work |
| Removal | Temporary wiring must be removed immediately upon completion of construction or the purpose for which it was installed |
Wiring rules (590.4)
- Services must meet Article 230.
- Feeders must originate in an approved distribution center, and may use multiconductor cord or cable listed for hard or extra-hard usage.
- Branch circuits must originate in an approved power outlet or panelboard, and may use multiconductor cord or cable of the same types. All conductors of a circuit, including the EGC, run together.
- Receptacles must be grounding type, electrically connected to an EGC, and on construction sites they may not be installed on branch circuits that supply temporary lighting.
- Disconnecting means: suitable disconnecting switches or plug connectors at the distribution center to disconnect all ungrounded conductors of each temporary circuit; multiwire branch circuits need simultaneous disconnection of all ungrounded conductors.
- Lamp protection: lamps for general illumination must be protected from accidental contact or breakage by a suitable luminaire or lampholder with a guard.
- Splices: on construction sites, a box is not required for splices in multiconductor cord or cable assemblies if equipment grounding continuity is maintained, with or without the box.
- Protection and support: cords and cables must be protected from accidental damage, sharp corners, and pinch points, and supported at intervals that protect them. Vegetation may not support overhead spans of branch circuits or feeders, except for holiday lighting with strain relief and other protections.
GFCI protection (590.6)
- 590.6(A): all 125 V, single-phase, 15-, 20-, and 30-ampere receptacle outlets that are not part of the permanent wiring of the building or structure and are used by personnel must have GFCI protection for personnel. This includes receptacles on portable generators and those supplied from permanent wiring but used for temporary power, unless already protected.
- 590.6(B): other receptacle outlets used for temporary power, such as 250 V or higher-amperage receptacles, must also have ground-fault protection as described in 590.6(B), which recognizes Class A GFCIs and special-purpose GFCIs for higher-voltage circuits.
- Listed cord sets or devices with GFCI protection may be used in some cases where permanent GFCI protection is not available.
Worked example: a Minnesota county fair
A county fair midway has a ride supplied from a portable generator and food stands supplied from temporary panels.
- Ride location: keep the ride at least 15 ft in any direction from overhead distribution lines of 600 V or less, other than its own supply conductors.
- Cords: listed extra-hard usage, wet-location and sunlight-resistant cords; across walkways, cover them with nonconductive mats.
- Receptacles: 125 V, 15- and 20-ampere receptacles readily accessible to the public or used for setup are GFCI protected.
- Temporary panels for the food stands: grounding-type receptacles, GFCI protected, with the wiring removed when the fair ends.
What is the minimum number of persons for which a building or portion of a building must be designed or intended to be covered by Article 518 as a place of assembly?
50
200
300
100
How long may temporary electrical power and lighting for holiday decorative lighting remain in place under 590.3?
30 days
60 days
90 days
180 days
On a construction site, a contractor plugs a saw into a 125 V, 30-ampere receptacle on a temporary power pole. What protection does 590.6(A) require?
GFCI protection for personnel
None, because 30-ampere receptacles are exempt
AFCI protection
Surge protection only
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