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2005 NEC Changes Summary Articles 525 through 590

ARTICLE 525 Carnivals, Circuses, Fairs, and Similar Events

These locations (carnivals, circuses, fairs, and similar events) are similar to assembly occupancies [Article 518], but there's a big difference. The assemblies occupancies covered by Article 518 aren't temporary. Another big difference is that the items covered by Article 525 include such things as amusement rides and attractions.

See if you can spot other similarities, as well as differences, between Article 518 and Article 525 as you study. Being aware of these will help you understand both articles better.

  • This rule was proposed to reduce the likelihood of electric shock. All sources of supply, separated by less than 12 ft, for rides, attractions, and other structures must now be bonded to the same grounding electrode system.

  • This section was extensively rewritten to clarify where GFCI protection is required, where GFCI protection is not required, and where GFCI protection is not permitted.

ARTICLE 547 Agricultural Buildings

Two factors have a tremendous influence on the lifespan of agricultural equipment: dust and moisture.

Dust gets into mechanisms and causes premature wear. But with electricity on the scene, dust adds two other dangers: fire and explosion. Dust from hay, grain and fertilizer is highly flammable. Litter materials, such as straw, are also highly flammable. The excrement from farm animals may cause corrosive vapors that eat at mechanical equipment but can also cause electrical equipment to fail. For these reasons, Article 547 includes requirements for dealing with dust and corrosion.

Another factor to consider in agricultural buildings is moisture, which causes corrosion. Water is present for many reasons, including wash down. Thus, Article 547 has requirements for dealing with wet and damp environments. Article 547 also includes other requirements. For example, it requires you to install equipotential stray voltage planes in all concrete floor confinement areas of livestock buildings containing metallic equipment accessible to animals and likely to become energized.

Livestock animals have a very low tolerance to small levels of stray electrical current, which can cause loss of milk production and, at times, livestock fatality. As a result, the NEC contains specific requirements for an equipotential stray voltage plane for buildings that house livestock.

  • The rules for GFCI protection of receptacles were relocated from 547.10(B) to 547.5(G). In addition, general-purpose receptacles located in dirt confinement areas for livestock must now be GFCI protected.

  • Section revised to clarify when an equipotential stray voltage plane is required in livestock buildings. Previous Codes required an equipotential stray voltage plane where metallic equipment was "likely to become energized."

ARTICLE 551 Recreational Vehicles and Recreational Vehicle Parks

Article 551 is similar to Article 550. After all, RVs are similar to mobile homes. While mobile homes are essentially trailers, RVs are essentially vehicles. Thus, RVs have their own article. RVs also have voltage converters, which mobile homes do not have. Other differences emerge as you look more closely.

While most of the requirements in Parts II and III apply to the RV manufacturer, an electrician doing work in an RV must also comply with these requirements.

If you're going to install an engine generator for an RV, you'll need to understand Part IV. Parts V and VI are primarily for RV manufacturers.

The typical electrician starts to get involved in Article 551 with Part VII, which provides the requirements for power distribution systems in RV parks. Perhaps the most important aspect of Part VII is understanding how to calculate loads and apply the demand factor, based on the number of RV sites in the park.

  • Text revised to increase the number of 50A, 125/250V receptacle recreational vehicle sites from 5 percent to 20 percent. This change was based on a survey of 500 campgrounds involving 45,000 recreational vehicle sites, which showed that an average of 18 percent of the sites provide 50A 125/250V receptacles.

ARTICLE 555 Marinas and Boatyards

Water level isn't constant. As the earth and the moon play their eons-old game of tug-of- war, oceans, lakes, rivers, and other bodies of water rise and fall at the shoreline. Other forces also cause the water level to change. For example, lakes and rivers vary in depth in response to rain. The variations can sometimes be dramatic.

To provide power to a marina or boatyard, you must allow for the variations in height between the point of use and the power source. Article 555 addresses this issue.

But that's not the only issue involved with marinas and boatyards. As you might expect, Article 555 also presents requirements for accommodating the high levels of moisture inherent in these installations. Boatyard and marina installations pose further challenges as well. For example, sunlight reflected off the water is much more intense than it would otherwise be-and this has implications for insulation. Other factors to consider include temperature extremes, increased abrasion, oil, gasoline, diesel fuel, ozone, acids, and chemicals.

Then, of course, docking a boat isn't as easy as pulling into a shopping center parking spot with your automobile. Electrical equipment must meet certain spatial requirements, such as not interfering with mooring lines or masts.

Article 555 begins with the concept of the electrical datum plane. You might think of it as the border of a "demilitarized zone" for electrical equipment. Or you can think of it as a line that marks the beginning of a "no man's land" where you simply don't place electrical equipment. Once you determine where this plane is, don't locate transformers, connections, or receptacles below that line.

  • Change requires electrical wiring and equipment to be on the opposite side from the liquid piping system of motor fuel dispensers.

  • Electrical wiring and equipment at facilities used to repair marine craft must now comply with the installation requirements of Article 511 Commercial Garages, Repair, and Storage.

  • The requirements for Temporary Installations were relocated from Article 527 to Article 590 to remove any confusion regarding its application to the entertainment industry articles.

ARTICLE 590 Temporary Installations

It's a common misconception that temporary wiring meets a lower standard than that of other wiring. In truth, it merely meets a different standard. The same rules of workmanship, ampacity, and circuit protection apply to temporary installations as to other installations.

So how is a temporary installation different? In one sense, it does meet a lower standard. For example, you can use Types NM and NMC rather than the normally required raceway-enclosed wiring-without height limitation. And you do not have to put splices in boxes.

You must remove a temporary installation upon completion of the purpose for which it was installed. If the temporary installation is for holiday displays, it cannot last more than 90 days.

Article 590 addresses practicality and execution issues inherent in temporary installations, thereby making the installation less time consuming to install.

  • Revised text clarifies that Type NM cable used for temporary feeder installations isn't limited by building height, construction type, or concealment.

  • Revised text clarifies that Type NM cable used for temporary branch-circuit installations isn't limited by building height, construction type, or concealment.

  • New exception recognizes that in many cases the only available support for holiday branch circuit lighting is live vegetation (trees).

Mike Holt's Comment: If you desire more information about any of the above changes, be sure to order my Changes book and/or library (Video/DVD).

12a. NEC Code Changes Textbook
Mike Holt’s Illustrated Changes to the NEC 2005 textbook is here! So, get ready now!

A new Code cycle has begun and it’s time to adapt to the 2005 NEC. Don’t let the scale of this change intimidate you. With Mike Holt’s Illustrated Changes to the NEC 2005, you’ll be up-to-speed in no time. Nearly 5,000 changes were proposed for the 2005 NEC! Over 225 of them will have a significant impact on designing, installing and inspecting electrical systems. Mike takes you through these changes, which he considers to be of critical importance. You’ll be able to easily gauge the impact of these changes apply them. This 120-page comprehensive full-color textbook includes 198 color illustrations for reference.

Subjects include:

  • General Requirements
  • Circuits and Protection
  • Grounding versus Bonding
  • Wiring Methods
  • Equipment for General Use
  • Special Occupancies
  • Special Equipment
  • Special Conditions
  • Limited Energy and Communications Systems

Why do Mike’s books give you the edge? Because of the extra effort put forth to make these changes easy-to-follow. Each change includes:

  • Cross references to other related Code requirements to help you develop a better understanding of how the Code rules relate to one another.
  • Background information for each change along with explanations, which are delivered in Mike’s trademark style… easy-to-understand.
  • Author’s Comments – Mike speaking to you directly about something that he feels should be brought to your attention.
  • Full-color detailed graphics to reinforce those difficult concepts and provide instant understanding.

Product Code: 05BK
ISBN: 1-932685-27-8

Pages: 120
Illustrations: 198


Table of Contents
Sample Pages
Sample Graphic


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