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Significant Proposals for 2005 NEC Part VI

As Reviewed by Mike Holt

The following text is a quick summary of the proposed changes for the 2005 NEC. This document is a work in progress and many will be changed by the Code panel over the next few months. Some of these you might find important to your work and you might want to follow their progress with me. Therefore, each week I will email you a few of these changes.

Each proposed change has a Report on Proposal (ROP) number, like 1-25. This number reflects the Proposal Number and all action on this proposal can be viewed in the following PDF document NEC Part2.

As always, I am looking to improve our products, so if you feel you have anything to contribute, please let me know at Mike@MikeHolt.com.

V. Bonding

5-185
250.92 Services.
(B) Method of Bonding at the Service. Text revised to require "other approved devices" used for bonding of service raceways to be "listed."

5-189
250.100 Bonding in Hazardous (Classified) Locations
Change prohibits the use of the grounded (neutral) conductor for bonding metal parts in hazardous locations. In addition, it clarifies that metal raceways must be bonded in accordance with this section, whether or not equipment grounding (bonding) conductors are installed in the metal raceway.

Author's Comment: The equipment grounding (bonding) conductor inside a metal raceway is not to be used as a substitute for the bonding requirements of this section.

5-197
250.104 Equipment Bonding Jumpers.
(B) Other Metal Piping. Text revised to clarify when metal piping systems, including gas piping, is required to be bonded.

5-200
250.104 Equipment Bonding Jumpers.
Text revised to clarify the bonding requirements for exposed interconnected structural steel forms a metal building frame is not intentionally grounded.

5-202
250.112 Fastened in Place or Connected by Permanent Wiring Methods (Fixed) - Specific
Change clarifies that metal parts of electrical equipment must be bonded to the power supply, not grounded to the earth!

5-216
250.118 Types of Equipment Grounding Conductors.
(5) Flexible Metal Conduit (FMC). New text specifies when an equipment (bonding) conductor is required to be installed.

5-218
250.118 Types of Equipment Grounding Conductors.
(6) Liquidtight Flexible Metal Conduit (LFMC). New text specifies when an equipment (bonding) conductor is required to be installed.

5-211
250.118 Types of Equipment Grounding Conductors.
New exception requires a "wire type" equipment grounding (bonding) conductor in all metal raceways located on rooftops.

Author's Comment: Strange that an exception contains a requirement that is more stringent than the general rule.

5- 220
250.119 Identification of Equipment Grounding (Bonding) Conductors
New sentence limits the use of the color green as well as green with yellow striped insulation to identify equipment grounding (bonding) conductors.

5-219
250.119 Identification of Equipment Grounding (Bonding) Conductors
(A) Conductors Larger Than 6 AWG
(1) Conductor. New exception identifies that equipment grounding (bonding) conductors 4 AWG and larger in conduit bodies are not required to be marked green or green with a yellow stripe.

5-229
250.122 Size of Equipment Grounding Conductors.
(D) Motor Circuits. Revised text clarifies how to size the equipment grounding (bonding) conductor for motor circuits.

5-229
250.122 Size of Equipment Grounding Conductors.
(G) Feeder Taps. New rule specifies how to size the equipment grounding (bonding) conductor for feeder taps.

5-235
250.140 Frames of Ranges and Clothes Dryers.
Section was rewritten to make it easier to understand and apply the bonding requirements for ranges and clothes dryers.

5-237
250.142 Use of Grounded Circuit Conductor for Grounding Equipment.
(B) Load-Side Equipment. The exception, which permitted the dangerous practice of bonding the meter enclosures to the grounded (neutral) on the load side of the service disconnect, was deleted.

Author's Comment: Meter enclosures are now readily available with neutral terminations that can be insulated from the metal enclosure.

5-239
250.146 Connecting Receptacle Grounding Terminal to Box.
(A) Surface Mounted Box. New sentence clarifies how to ensure direct metal-to-metal contact between the metal mounting yoke of a receptacle and the metal box, when a bonding jumper is not installed from the grounding (bonding) terminal of the receptacle.

Author's Comment: This rule only applies when relying on direct contact from the device yoke to a metal box for bonding.

5-238a
250.146 Connecting Receptacle Grounding Terminal to Box.
(B) Contact Devices or Yokes. This section for "self-grounding receptacles" was revised to require the receptacle to be "listed as self-grounding".

5-244a
250.147 Bonding of General-Use Snap Switches
The bonding requirements for general use snap switches were relocated from 404.9(B) to this section.

5-248
250.148 Continuity and Attachment of Equipment Grounding Conductors to Boxes.
Changes include formatting into subsections with titles and editorial improvements.


Article 280 Surge Arresters

5-262
280.4 Surge Arrester Selection.
(A) Circuits of Less Than 1000 Volts.
(3) Short-Circuit Rating. New item clarifies when surge arresters are required to be marked with a short circuit current rating and where they cannot be installed because of excessive fault current.


Article 285 Transient Voltage Surge Suppressors: TVSSs

5-267
285.3 Uses Not Permitted.
Text revised in item (2) on when transient voltage surge suppressors are permitted on ungrounded systems, impedance grounded systems, and corner grounded delta systems.


Chapter 3 Wiring Methods and Materials

Article 300 Wiring Methods

3-24
300.4 Protection Against Physical Damage
(A) Cables and Raceways Through Wood Members.
(1) Bored Holes. New exception permits nail plate less than 1/16 in. thick if listed for this purpose and marked so the inspector can verify its listing.

Author's Comment: Hardened steel plates thinner than 1/16 inch have been tested and found to provide better protection from screw and nail penetration than the thicker plates.

3-26
300.4 Protection Against Physical Damage
(A) Cables and Raceways Through Wood Members.
(2) Notches in Wood. Additional requirement permits nail plate less than 1/16 in. thick if listed for this purpose and marked so the inspector can verify its listing.

3-27
300.4 Protection Against Physical Damage
(A) Cables and Raceways Through Wood Members.
(2) Notches in Wood. New exception permits nail plate less than 1/16 in. thick if listed for this purpose and marked so the inspector can verify its listing.

3-28
300.4 Protection Against Physical Damage
(B) Nonmetallic-Sheathed Cables and Electrical Nonmetallic Tubing Through Metal Framing Members.
(2) Nonmetallic-Sheathed Cable and Electrical Nonmetallic Tubing. New exception permits nail plate less than 1/16 in. thick if listed for this purpose and marked so the inspector can verify its listing.

3-17
300.4 Protection Against Physical Damage
(D) Cables and Raceways Parallel to Framing Members and Furring Strips. Text revised to expand the requirements when the 1-1/4" cable clearance is required when the cable is run parallel to framing members.

3-33
300.4 Protection Against Physical Damage
(D) Cables and Raceways Parallel to Framing Members and Furring Strips. New exception permits nail plate less than 1/16 in. thick if listed for this purpose and marked so the inspector can verify its listing.

3-33
300.4 Protection Against Physical Damage
(E) Cables and Raceways Installed in Shallow Grooves.
New exception permits nail plate less than 1/16 in. thick if listed for this purpose and marked so the inspector can verify its listing.

3-51
300.6 Protection Against Corrosion and Deterioration.
This section was re-written to better cover all possible types of corrosion or deterioration to metallic systems. In addition, the text was revised to make it clear that where corrosion-resistant compound is required to be listed.


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