If you do electrical work with temporary events, you obviously need to understand Article 525, which covers the installation of portable wiring and equipment for carnivals, circuses, exhibitions, fairs, traveling attractions, and similar functions [525.1]. But what if you don't do such work — is it still worthwhile to understand the requirements of this Article? Absolutely! If you review Article 525, you see that it addresses such things as equipment protection, wiring methods, and GFCIs. Therefore, it's an excellent text for seeing how some key NEC concepts work together.
Maybe you volunteered to chair a committee that oversees a carnival or fair for your employer, church, civic group, alumni association, or school. An understanding of Article 525 allows you to provide good advice. Or maybe you take your child or grandchild to the circus. With your knowledge of Article 525, you can quickly do a visual inspection of rides or other attractions that could endanger the child.
We'll discuss the finer points of this Article from the viewpoint of the installer, but will also identify some easy inspection points along the way.
When you take a closer look at Article 525, a couple of questions arise. “Aren't these just like assembly occupancies? Why do we need Article 525, if Article 518 covers the same thing?”
Yes, these locations are similar to assembly occupancies [Article 518], but they are not the same. In fact, there are two big differences:
Article 525 applications are temporary; Article 518 occupancies are not.
Article 518 does not cover amusement rides and attractions; Article 525 does.
Another Article that is often mistakenly applied to these events is Article 590, which governs temporary installations. While carnivals, fairs, and similar events are indeed temporary in nature, they also have a distinct safety hazard associated with them — the general public, particularly children, will be in intimate contact with electrical equipment. Because of this, Article 525 contains more stringent requirements than those installations typically found at the job site. Also, note that Article 525 does not address:
- Audio signal processing equipment
Anyone setting up a sound stage will need to refer to Article 640 [525.3(C)].
- Attractions that utilize water
Anyone installing such things as swimming pools, fountains, dunk tanks, bumper boats, and duck ponds needs to refer to Article 680 [525.3(D)].
If you use electric motors to circulate water in a tank that guests might touch, Article 680 applies. A key provision: 680.22(A)(1) permits a GFCI-protected single locking-type receptacle for a water-pump motor between 5 feet and 10 feet from the water (Fig. 1 on page 58).
Overhead conductor clearances
If you are that parent or grandparent mentioned earlier, overhead clearance requirements make easy inspection points. Overhead conductors must have a clearance of 15 feet from amusement rides and attractions (except, of course, for the conductors that supply power to the ride or attraction) [525.5(B)]. For overhead conductors installed outside tents and concession areas, the vertical clearance requirements of 225.18 apply [525.5(A)]. The minimums are:
10 feet above finished grade, sidewalks, platforms, or projections from which they might be accessible to pedestrians for 120V, 120/208V, 120/240V, or 240V circuits.
12 feet above residential property and driveways, and those commercial areas not subject to truck traffic for 120V, 120/208V, 120/240V, 240V, 277V, 277/480V, or 480V circuits.
18 feet over public streets, alleys, roads, parking areas subject to truck traffic, driveways on other than residential property, and other areas traversed by vehicles (such as those used for cultivation, grazing, forestry, and orchards).
Service equipment must not be accessible to unqualified persons, unless the equipment is lockable [525.10(A)]. See the Article 100 definition of “Accessible” as it relates to equipment and service equipment. This is another easy inspection point — also check to see that this equipment is actually locked.
Mount service equipment on solid backing. Many temporary installations fail in this regard — remember that the mounting is a critical safety issue. If the equipment is not of weatherproof construction, install it in a way that protects it from the weather [525.10(B)].
Where multiple services or separately derived systems (or both) supply rides and other structures, are any sources of supply separated by less than 12 feet? If so, bond these to the same grounding electrode (earthing) system [525.11]. The 12-foot separation of structures is simply a nominal value; there is no strong technical reason for this measurement. Having a specific value allows consistent enforcement.
Where electrical equipment or wiring is subject to physical damage, provide it with mechanical protection [525.6]. This requirement applies to the entire installation, not just the service.
Flexible cords or cables in compliance with Article 400 must be listed for extra-hard usage. When used outdoors, they must be listed for wet locations and must be sunlight resistant. Flexible cords or cables must be continuous without splice or tap between boxes or fittings [525.20], and they can never be used where subject to physical damage [400.8(7)].
You can use single conductor cable in sizes 2 AWG or larger. You can also use open conductors that are part of a listed assembly, or you can use open conductors in festoon lighting per Article 225 (Fig. 2 on page 59) [525.20(C)].
Do not lay cord connectors on the ground, unless they are listed for wet locations. Connectors placed in audience traffic paths or areas accessible to the public must be guarded (Fig. 3 on page 59) — this is another easy inspection point.
A ride or structure must not support wiring for an amusement ride, attraction, tent, or similar structure unless the ride or structure is specifically designed for this purpose.
Two related requirements for rides and structures [525.21]:
Each ride and concession must have a fused disconnect switch or circuit breaker within sight and within 6 feet of the operator's station.
Inside tents and concession areas, securely install the wiring for lighting. If the wiring is subject to physical damage, provide mechanical protection. Protect all lamps for general illumination from accidental breakage by a suitable luminaire or lampholder with a guard.
GFCI-protected receptacles and equipment
GFCI protection is not required for receptacles of the locking type [525.23]. You may decide to add an extra margin of safety by installing it. But don't blindly install GFCI devices everywhere — GFCI protection is not permitted for egress lighting.
GFCI protection is required for all:
15A and 20A, 125V nonlocking type receptacles used for disassembly and reassembly of amusement rides and attractions or readily accessible to the public.
Equipment readily accessible to the public, if supplied from a 15A or 20A, 120V branch circuit. This rule applies even if the equipment is not cord and plug connected.
You can use listed cord sets incorporating GFCI protection (Fig. 4). GFCI protection for personnel can be an integral part of the attachment plug, or it can be located in the power-supply cord if it is within 12 inches of the attachment plug.
Grounding and bonding
You must bond the following equipment together, if they are connected to the same power source [525.30]:
Metal raceways and metal-sheath cables.
Metal frames and metal parts of rides, concessions, tents, trailers, trucks, or other equipment that contain or support electrical equipment.
Ground the metal parts of all electrical equipment to the grounded (neutral) conductor at the service disconnecting means per 250.24(C) (or the separately derived system per 250.30(A)(1)) [525.31].
Someone must verify the continuity of the equipment grounding (bonding) conductor each time anyone connects the portable electrical equipment [525.32]: Verification of the equipment grounding (bonding) conductor is necessary for electrical safety. However, this requirement is vague. It doesn't specify:
Who is required or qualified to perform the verification.
What verification means.
Where to record the verification.
How you must verify the grounding (bonding) conductor.
Which circuits you must verify.
To avoid liability problems, talk to your insurer and the AHJ for guidance and their requirements — and then get those in writing.
With your knowledge of Article 525, you can prevent tragedies at events that were meant to be fun. You can do this whether you are the installer, inspector, project manager, advisor, or customer.