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Code Alert:  Maryland, 16 February 2010

Montgomery County Maryland Adopts the 2008 National Electrical Code

On January 12, 2010, the Montgomery County Council approved Executive Regulation No. 15-09. This Regulation adopts the 2008 National Electrical Code (NEC) with local amendments and supersedes Executive Regulation No. 25-04 which adopted the 2002 NEC on April 1, 2005. The 2008 National Electrical Code (NEC) with local amendments becomes effective on March 15, 2010 and applies to all electrical equipment and installations within Montgomery County.

Executive Regulation No. 25-04 had fourteen amendments to the 2002 NEC. The new regulation retains all previous amendments and adds a new amendment. The new amendment was added to Section 230.70(A)(1) of NEC 2008 and requires a shunt trip to disconnect the electrical service in new buildings, excluding one and two family dwellings. The shunt trip is to be located in the Fire Command Center, or where there is no Fire Command Center, at the fire alarm annunciator, or where there is no fire alarm annunciator or Fire Command Center in an appropriately sized and weatherproof fire department access box on the address side of the building. The requirement also applies in existing buildings, excluding one and two family dwellings, where there are significant upgrades to the building electrical service, such as modifying or replacing the switchgear. The amendment was added to correlate with the requirements of Section 11.1.7 Building Disconnect Access of NFPA 1 Uniform Fire Code.

The other amendments include:

  • A definition for “Fixed Appliance”

  • A revised definition for “Building”, which correlates with the definition and requirements of the ICC International Building Code for fire walls.

  • Additional text to Section 210.5(c) requiring color coding of conductors

  • An individual branch circuit except for electric baseboard heaters, appurtenant equipment to furnaces, such as humidifiers and electronic air cleaners, and other equipment having motors rated 1/4 hp or less.

  • An individual branch circuit of copper wire not smaller than size 10 AWG for each wall‑mounted oven and each counter‑mounted cooking unit

  • Limits on general lighting branch circuits in dwellings to not more than twelve “power-consuming outlets”.

  • Limits on general appliance branch circuits in dwellings to not more than eight receptacle outlets.

  • A GFCI protected receptacle, accessible at grade level, must be installed on the outside of the new addition. made to an existing dwelling which has no outside ground‑fault circuit-­interrupter (GFCI) receptacle.

  • A minimum 150 amperes rated service disconnecting means for one-family dwellings.

  • A concrete encased electrode is to be used as the principle grounding element for all new structures, both residential and commercial.

  • Aluminum and copper‑clad aluminum conductors to service entrance and feeder applications are limited to a minimum size of 2 AWG.

  • All luminaire s installed in suspended ceilings must be supported from the building structure directly with no less than two separate No. 12 or larger steel wires extending from opposite corners of the luminaire with each wire independently attached to the building structure. Luminaires not more than 24 inches in diameter require are least one wire. Note: The section in this amendment is incorrectly identified as 410.16(C).

  • Each individual room air-conditioning unit, regardless of its current rating, must be served by an individual circuit of not less than 12 AWG copper wire, and must terminate in a single receptacle.

  • Any building in which standpipes are installed must have one 30‑ampere, 120‑volt circuit installed for each standpipe riser, supplied from the emergency panel. The wiring method for exposed work must be galvanized, threaded metal conduit. Supply wiring must be rated at least 75°C and one single 20-ampere three-wire twist-lock receptacle must be installed at each hose valve connection.

  • Contact: Gil Moniz: gilmoniz@nema.org


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