October 24, 2005 A PRIMEDIA Property Vol. III No. 20



CONTENTS
Class 1, Class 2, and Class 3 Remote-Control, Signaling, and Power-Limited Circuits
725.3 Other Articles

A Medicine Chest That Bites?

What's Wrong Here?

Code Q&A

Code Quiz

2008 Proposals Due Soon

Innovative Technology Services

Grounding vs Bonding Seminar


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    Top 2005 Code Changes
    Class 1, Class 2, and Class 3 Remote-Control, Signaling, and Power-Limited Circuits
    725.3 Other Articles

    By Mike Holt
    Where necessary for their direct action upon, or sensing of the contained air, Class 2 and Class 3 cables can be installed in ducts or plenum if they're installed in electrical metallic tubing, intermediate metal conduit, or rigid metal conduit as required by 300.22(B). (Note: Code text has been paraphrased.)

    What the Code says:
    (C) Ducts, Plenums, and Other Air-Handling Spaces.
    Ducts and Plenums. Class 2 and Class 3 cables installed within ducts or plenums must be installed in accordance with 300.22.
    (Text new to the Code is underlined.)

    You can install nonplenum-rated Class 2 and Class 3 cables within electrical metallic tubing, as permitted by 300.22(C), above a suspended ceiling or below a raised floor that is used for environmental air. Type CL2 and Type CL3 cables installed beneath a raised floor in an information technology equipment room (computer room) aren't required to be plenum rated [300.22(D) and 645.5(D)(5)(c)].

    What the Code says:
    Other Air-Handling Space. Plenum-rated Class 2 and Class 3 cables [725.82(A)], and plenum signaling raceways [725.82(I)] with plenum-rated cables, can be installed above a suspended ceiling or below a raised floor used for environmental air movement [725.61(A)].
    (Text new to the Code is underlined.)

    Behind the change: These changes clarify the types of cables and raceways permitted in ducts, plenums, and other space used for environmental air.


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    Nightmare Installations
    A Medicine Chest That Bites?
    Several years ago, my son complained he got "bit" while reaching for his toothbrush in the medicine chest of our bathroom. He was touching the water faucet at the time. While investigating this claim, I discovered that the previous homeowners had removed an existing light fixture when they installed the medicine chest. The light fixture was no longer needed because the new metal medicine chest came with its own lights. What I discovered was the previous owners had replaced the old light fixture socket with a screw-in adapter for a two-prong plug. The new medicine chest was connected to the adapter with simple lamp cord. Over time, excess heat caused the lamp cord to become brittle. Once the insulation cracked, it exposed the conductor, which made contact with the ungrounded metal cabinet. I immediately replaced the old lamp socket with a GFCI-type receptacle to eliminate the hazard.
    Michael Caesare
    Oakland, Calif.

    Send your 200-word story to us and it may appear in a future issue of CodeWatch. Authors of stories chosen will receive $25.


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    Code Challenge
    What's Wrong Here?
    By Joe Tedesco
    Got a guess for how this installation violates the NEC? Visit EC&M's Web site to see the answer.

    Hint: Cool splice for an air conditioner, huh?

    Code Q&A
    By Mike Holt
    Q. How close can I run underground service conductors in a raceway to an outdoor pool?

    Visit EC&M's Web site to see the answer.

    Code Quiz
    By Steven Owen
    Q.When grounding branch circuits -- with respect to grounding requirements for receptacles and fixed equipment -- in patient care areas of hospitals (critical care or general care areas), which of the following statements is correct?

    A) You can use an internal equipment grounding conductor of a metallic raceway or cable, the metal of the metallic raceway, or a metallic cable armor or sheath assembly to ground receptacles or fixed equipment.
    B) You can only use a properly sized internal equipment grounding conductor within a metallic raceway.
    C) You can only use a properly sized internal equipment grounding conductor in a nonmetallic raceway.
    D) You can use any properly sized equipment bonding jumper installed external to the wiring method of choice.

    Visit EC&M's Web site for the answer and explanation.


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    Code News Updates
    2008 Proposals Due Soon
    Seems like it wasn't all that long ago that you received your copy of the 2005 NEC, doesn't it? Well, guess what, the first official step in creating the 2008 NEC occurs in just a few days. But you better act fast. Code-making panels are soliciting change proposals for just a few more days. Don't miss your chance to voice your concerns about that requirement that's been bugging you. Change proposals are due by 5 p.m. on Nov. 4.

    A copy of the proposal form is available in the back of the 2005 NEC or at NFPA's Web site.

    Innovative Technology Services
    On July 29, the NFPA's Standards Council issued a Tentative Interim Agreement (TIA) to the 2005 edition of the NEC, which revises sections 680.26(C) and 680.26(C)(1). The changes are focused on the equipotential bonding grid requirements for pools and paved walking surfaces adjacent to a below-grade pool.

    The TIA will become a proposal for the 2008 edition of the Code and be subject to the procedures of the standards-making process at that time. The effective date of the TIA will be Aug.18, 2006.

    Shows and Events
    Grounding vs Bonding Seminar
    Grounding and bonding of electrical systems, sensitive electronic, and communications equipment is the most important and least understood activity in the electrical, data processing, and communications industry. At four two-day seminars, Code expert Mike Holt will explain the basics as well as the advance concepts necessary to understand the practical grounding and bonding rules in the NEC for systems not over 600V. Download the conference brochure for specific dates and locations.

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