By: Jim Herrick                                          Publish Date: 06/07/17

Introduction:    This is the first electrical information blog from Motion Labs. This and future blogs are intended to provide information to persons in the entertainment and event production industry to enhance their technical knowledge and provide a better understanding relating to many electrical aspects of equipment, wiring and safety.

Disclaimer: Although the vast majority, of the information provided, is indisputable, there are cases where some of the information is “open to interpretation”, especially in the area of the National Electrical Code (NEC).

In such cases the “final say” is up to your local “Authority Having Jurisdiction” (AHJ), usually the electrical inspector. The information provided is based on the National Electrical Code (NEC), however, these requirements may be accepted as written or modified by local authorities (by law), especially in large cities. This column does not necessarily represent the opinion of the editorial board or Motion Labs and its owners.



My intent wasn’t to start-off with such an argumentative subject, but this came up recently a couple of times,

So here we go…

This blog is in reference to the possible “misapplication” of article 590 (NEC 2014), “Temporary Installations”.

This article states that GFCI protection is required on all 15A, 20A & 30A receptacles. There is, I believe, a misapplication of this code article that mandates GFCIs be used “on stage”.

Nuisance tripping of GFCI devices, on stage, could be a catastrophe during a performance.

I can see it now… 20,000 fans in an auditorium, each paying $100 to $300 a ticket for a major rock concert.

The first strum on the guitar, the GFCI trips… Now you have a serious problem!

I guess you could argue about the code after the riot, but that’s really bad timing.

Normal leakage current from multiple amplifiers, hoist motors, surge suppressors and other stage equipment can exceed the trip current of GFCI devices. GFCI devices, for protection of personnel, trip at around 5ma (.005 amps). In all cases a proper grounding / bonding scheme is essential for safety, and mitigates the need for GFCI protection. Many electrical professionals do not understand how and where leakage currents flow, thus adding to the confusion. Leakage currents are not ground faults, in the normal sense, but they can trip GFCIs.

I understand why Article 590 may be misapplied… “Theatrical performances” are generally “temporary” in nature, but there are other articles in the code that must be specifically adhered to regarding this type of temporary installation, such as:

(518) Assembly Occupancies;

(520) Theaters, Audience Areas of Motion Picture and TV Studios Performance Areas, and Similar Locations;

(525) Carnivals, Circuses, Fairs and Similar Events;

(530) Motion Picture and TV Studios and Similar Locations.

If there is a code specifically relating to what you’re doing… That’s the code that should be adhered to.

If there wasn’t a specific code for theaters, then Article 590 could be applied, but such is not the case; there is a code just for temporary theater installations (Article 520), that’s why Article 590 does not apply to theaters.

An exaggerated example would be to apply the “Swimming Pool” GFCI requirement to theater installations.

In my opinion, Applying Article 590 instead of 520 for theaters, is almost as bad.

It is clear (to me) that Article 590 is to be applied to “construction sites”. In fact the term “construction sites” is mentioned several places in NEC article 590. Decorative holiday lighting is also included in article 590.

Article 590.6(B) specifically defines what scenarios that apply to this article, which states:

“This section shall apply only to temporary wiring installations, used to supply temporary power to equipment used by personnel during construction, remodeling, maintenance, repair, or demolition of buildings, structures, equipment, or similar activities”.

In addition, Article 518.3(B), “Assembly Occupancies” also states:

“The ground-fault circuit-interrupter requirements of 590.6 shall not apply.”

Get the drift? …… Not stages.

The rationale for Article 590 GFCI requirements on construction sites is obvious: The possibility of misuse and damage to conductors and equipment is likely, this is not the case with temporary theatrical equipment wiring. In addition, qualified personnel (for temporary stage wiring) is a requirement in most jurisdictions.

There is a caveat which may apply: GFCI protected circuits should be available for the connection of construction hand tools (Drills, saws nail guns, and the like) during construction of sets and staging….. Here again this is “construction”, as defined in article 590. After construction is completed and/or inspected the GFCI requirement no longer applies.

There is no reference to “live performances” in Article 590, even though they are “temporary”.

This is especially reinforced by the fact that theaters are specifically covered in Article 520, which does not require GFCIs.

If the committee of experts, who wrote the code, had determined that GFCIs were required “on stage” it would be in Article 520.

There are special conditions that would require GFCIs for live performances, such as, shows that include a water feature, but what we’re talking about here is indoors in dry locations, however, GFCIs are not even required for “outdoor shows” per Article 520.10, which states, (in part): “Portable power distribution equipment not identified for outdoor use shall be permitted for temporary use outdoors, providing the equipment is supervised by qualified personnel while energized.” …… No mention of GFCIs.

If the AHJ (Electrical Inspector) elects to apply NEC Article 525 (Carnivals, Circuses, Fairs, and Similar Events), to your “live outdoor show”, GFCI’s are only required to be provided on 125-volt, 15 or 20 amp, branch circuits that are accessible to the general public, and are not provided with a “locking” device (Twist-Lock). Once again, not on stage. Refer to 2014 NEC Article 525.23 for complete wording.

Informational note:

In Europe they use a form of GFCI, which they term as: RCD (Residual Current Detector). These safety devices function similar to our GFCIs. The difference is that the “adjustable trip point” can be set to 30ma as compared to a GFCI, which trips at about 5ma. These devices are not common in the USA, and are relatively expensive (but are available), and provide a balance between additional safety and nuisance tripping.


The opinion, expressed herein, is only a personal interpretation. Check with your local authorities for final decisions on code matters. The above information and opinion represents only one point of view; it may or

may not be accepted by your local electrical inspector, who is the “Authority Having Jurisdiction” (AHJ).

Motion Labs is here to help.

We encourage you to ask questions, provide constructive criticism, and suggest subjects for future blogs.

Remember some of the subject matter may be argumentative in nature. If you disagree or need clarification, let us know.



Jim Herrick


About the author:

Jim Herrick, over 40 years’ experience in the electrical field. Licensed in the State of New Jersey as an Electrical Contractor (License #6748) and Electrical Inspector (License #7702). Of the 40 years’ experience, 30 of which, included work in the theatrical industry, which also included electrical equipment design for major companies in the industry.