AFCI Proposals for the 2005 NEC

Submitted by William H. King, Jr., Chief Engineer for Electrical and Fire Safety, Division of Electrical Engineering, US Consumer Product Safety Commission

PROPOSAL.

Section/Paragraph:     Art. 210, Part I. General Provisions, para. 210.12

Add a new 210.12 ( ) section to paragraph 210.12 as follows:

( ) Lighting and Appliance Branch Circuits in Dwelling Units. When the service equipment at a dwelling is replaced, a listed arc-fault circuit interrupter, branch/feeder type, or a listed arc-fault circuit interrupter, outlet branch circuit type, shall protect each branch circuit that existed prior to the replacement that serves 125-volt, single-phase, 15- and 20-ampere outlets for lighting and appliances. The arc-fault circuit interrupter, outlet branch circuit type, shall be installed at the outlet closest to, and within 3.0 m (10 ft) of the overcurrent device as measured along the branch circuit conductors.

FPN: See 230.XX for complementary requirement for service equipment.

(Editorial note: 230.XX is a proposed new section, submitted to the CMP 4 for Article 230, to complement the proposed new paragraph (B) to 210.12. For information purposes, the proposed new 230.XX reads as follow: Replacement of Service Equipment at Dwelling Units. When the service equipment at a dwelling is replaced, a listed arc-fault circuit interrupter, branch/feeder type, or a listed arc-fault circuit interrupter, outlet branch circuit type, shall protect each branch circuit that existed prior to the replacement that serves 125-volt, single-phase, 15- and 20-ampere outlets for lighting and appliances. The arc-fault circuit interrupter, outlet branch circuit type, shall be installed at the outlet closest to, and located within 3.0 m (10 ft) of the overcurrent device as measured along the branch circuit conductors.)

STATEMENT OF PROBLEM AND SUBSTANTIATION FOR PROPOSAL.

The new requirement for lighting and appliance branch circuits within existing dwellings that undergo service equipment replacement addresses the condition of wiring systems identified in technical studies sponsored by the U.S. Consumer Product Safety Commission (CPSC).  The 1987 CPSC report (“Residential Electrical Distribution System Fires”, Smith & McCoskrie) provided evidence that fires originating in branch circuit wiring predominately occurred in dwellings over 20 years old, with the highest rates of fires occurring in dwellings over 40 years old.  Older dwellings are frequently upgraded with replacement service equipment to increase the service rating to supply additional appliance and equipment loads.  However, existing lighting and appliance branch circuits are not replaced when the service is upgraded in many cases due to the increased cost, and/or the inability to evaluate the extent of degradation in aged circuits.  The branch circuit conductors are frequently located in concealed spaces surrounded with thermal insulation, and could be in a deteriorated condition at the time the service is upgraded.  This proposal is intended to provide extra protection with the addition of arc-fault circuit interrupter (AFCI) technology to address the potential fire hazards in existing branch circuits.  This proposal is not intended to apply AFCI devices as a substitute for replacing unsafe wiring.  Unsafe wiring should be replaced when it is identified, and the wiring methods should be done in accordance with the NEC.

In 1995 arc-fault detection was identified as a promising technology that could be applied to older homes to improve electrical safety by detecting symptoms that can cause fires (report “Technology for Detecting and Monitoring Conditions That Could Cause Electrical Wiring System Fires”, sponsored by CPSC and prepared by Underwriters Laboratories Inc.).  Shortly after this report was issued, the production of listed arc-fault circuit interrupter devices began.  In 1999 the NEC introduced the first AFCI requirement for branch circuit protection, limited to branch circuits supplying outlets in bedrooms.  When considering needs for additional AFCI protection, one of the priority locations is the older home that undergoes a service upgrade intended to extend the service life of the structure.  This is the situation where the existing, older branch circuits in the dwelling will be expected to continue to supply power for appliance and lighting loads in the years ahead.  These circuits need the benefit of the extra protection afforded by AFCI devices.

Other Considerations

PROPOSAL.

Section/Paragraph:     Art. 100, Part I.  General

Add the following definitions to Part I:

Arc-Fault Circuit Interrupter, Branch/Feeder Type. A device intended to protect the branch or feeder circuit from the effects of arc faults by recognizing characteristics unique to arcing and by functioning to de-energize the entire branch or feeder circuit when an arc fault is detected.

Arc-Fault Circuit Interrupter, Outlet Branch Circuit Type.  A device intended to be installed at the first outlet in a branch circuit to protect the branch circuit, outlet devices, and wires connected to outlet devices from the effects of arc faults by recognizing characteristics unique to arcing and by functioning to de-energize the circuit at the load side of the arc-fault circuit interrupter (including de-energizing receptacles provided on the arc-fault circuit interrupter outlet device).

STATEMENT OF PROBLEM AND SUBSTANTIATION FOR PROPOSAL.

Definitions for arc-fault circuit interrupters have been expanded from the definition that exists in Section 210.12 of the 2002 edition to coincide with the listing of new arc-fault circuit interrupter devices.  It is recommended that the definitions be re-located from Article 210 to Article 100 because a proposal has been submitted to include new requirements in both Articles 210 and 230.

Although AFCI devices currently available are incorporated within circuit breakers, AFCI devices have been listed that are incorporated into outlet devices.  While only AFCI/circuit breakers can de-energize the entire branch circuit, listed AFCI/outlet devices can be applied in applications where fuses are provided as the branch circuit overcurrent protection devices.  In addition, listed AFCI/outlet devices have been investigated and listed as an outlet branch circuit type with expanded arc detection capabilities, including sensing certain arcing conditions upstream of the AFCI/outlet device location, and sensing broader arcing conditions downstream of the AFCI/device location.  These safety devices will provide the broadest range of fire protection to the occupants of dwellings.

PROPOSAL.

Section/Paragraph:     Art. 230, Part V. Service Equipment – General, new Section 230.XX

Add new Section 230.XX as follows:

230.XX  Replacement of Service Equipment at Dwelling Units.  When the service equipment at a dwelling unit is replaced, a listed arc-fault circuit interrupter, branch/feeder type, or a listed arc-fault circuit interrupter, outlet branch circuit type, shall protect each branch circuit that existed prior to the replacement that serves 125-volt, single-phase, 15- and 20-ampere outlets for lighting and appliances.  The arc-fault circuit interrupter, outlet branch circuit type, shall be installed at the outlet closest to, and located within 3.0 m (10 ft) of the overcurrent device as measured along the branch circuit conductors.

FPN:  See 210.12 (B) for complementary requirement for branch circuits.

(Editorial note:  210.12 (B) is a proposed new paragraph submitted to the CMP for Article 210, to complement the proposed new Section 230.XX.  For information purposed, the proposed new paragraph (B) of Section 210.12 reads as follows:  Lighting and Appliance Branch Circuits in Dwelling Units.  When the service equipment at a dwelling is replaced, a listed arc-fault circuit interrupter, branch/feeder type, or a listed arc-fault circuit interrupter, outlet branch circuit type, shall protect each branch circuit that existed prior to the replacement that serves 125-volt, single-phase, 15- and 20-ampere outlets for lighting and appliances.  The arc-fault circuit interrupter, outlet branch circuit type, shall be installed at the outlet located closest to, and within 3.0 m (10 ft) of the overcurrent device as measured along the branch circuit conductors.)

STATEMENT OF PROBLEM AND SUBSTANTIATION FOR PROPOSAL.

A report issued by the U.S. Consumer Product Safety Commission in 1987 (“Residential Electrical Distribution System Fires”, Smith & McCoskrie) provided evidence that fires originating in branch circuit wiring predominately occurred in dwellings over 20 years old, with the highest rates of fires occurring in dwellings over 40 years old.  Older dwellings are frequently upgraded with replacement service equipment to increase the service rating to supply additional appliance and equipment loads.  However, existing lighting and appliance branch circuits are not replaced when the service is upgraded in many cases due to the increased cost, and/or the inability to evaluate the extent of degradation in aged circuits.  The branch circuit conductors are frequently located in concealed spaces surrounded with thermal insulation, and could be in a deteriorated condition at the time the service is upgraded.  This proposal is intended to provide extra protection with the addition of arc-fault circuit interrupter (AFCI) protection to address the potential fire hazards in existing branch circuits.  This proposal is not intended to apply AFCI devices as a substitute for replacing unsafe wiring.  Unsafe wiring should be replaced when it is identified, and the wiring methods should be done in accordance with the NEC.

In 1995 arc-fault detection was identified as a promising technology that could be applied to older homes to improve electrical safety by detecting symptoms that can cause fires (report “Technology for Detecting and Monitoring Conditions That Could Cause Electrical Wiring System Fires”, sponsored by CPSC and prepared by Underwriters Laboratories Inc.).  Shortly after this report was issued, the production of listed arc-fault circuit interrupter devices began.  In 1999 the NEC introduced the first AFCI requirement for branch circuit protection, limited to branch circuits supplying outlets in bedrooms.  When considering needs for additional AFCI protection, one of the priority locations is the older home that undergoes a service upgrade intended to extend the service life of the structure.  This is the situation where the existing, older branch circuits in the dwelling will be expected to continue to supply power for appliance and lighting loads in the years ahead.  These circuits need the benefit of the extra protection afforded by AFCI devices.

PROPOSAL.

Section/Paragraph:     Art. 210, Part I. General Provisions, para. 210.12

The recommendation is that Code-Making Panel No. 2 should request that Code-Making Panel No. 1 consider the following expanded definitions of arc-fault circuit interrupters and incorporate the definitions within Article 100 (a separate proposal to cover this change has been submitted to Code-Making Panel No. 1 for action.):

Arc-Fault Circuit Interrupter, Branch/Feeder Type.  A device intended to protect the branch or feeder circuit from the effects of arc faults by recognizing characteristics unique to arcing and by functioning to de-energize the entire branch or feeder circuit when an arc fault is detected.

Arc-Fault Circuit Interrupter, Outlet Branch Circuit Type.  A device intended to be installed at the first outlet in a branch circuit to protect the branch circuit, outlet devices, and wires connected to outlet devices from the effects of arc faults by recognizing characteristics unique to arcing and by functioning to de-energize the circuit at the load side of the arc-fault circuit interrupter (including de-energizing receptacles provided on the arc-fault circuit interrupter outlet device).

STATEMENT OF PROBLEM AND SUBSTANTIATION FOR PROPOSAL.

The definitions are expanded to coincide with the listing of new arc-fault circuit interrupter devices.  The definitions are moved to Article 100 because a proposal is being made to include requirements mentioning these devices in Article 230, in addition to requirements in Article 210.

Although AFCI devices currently available are incorporated within circuit breakers, AFCI devices have been listed that are incorporated into outlet devices.  While only AFCI/circuit breakers can de-energize the entire branch circuit, listed AFCI/outlet devices can be applied in applications where fuses are provided as the branch circuit overcurrent protection devices.  In addition, listed AFCI/outlet devices have been investigated and listed as an outlet branch circuit type with expanded arc detection capabilities, including sensing certain arcing conditions upstream of the AFCI/outlet device location, and sensing broader arcing conditions downstream of the AFCI/device location.  These safety devices will provide the broadest range of fire protection to the occupants of dwellings.

PROPOSAL.

Section/Paragraph:     Art. 210, Part I. General Provisions, para. 210.12

Revise the section of the paragraph covering dwelling unit bedrooms as follows:

( ) Dwelling Unit Bedrooms.  All branch circuits that supply 125-volt, single-phase, 15- and 20-ampere outlets installed in dwelling unit bedrooms shall be protected by an arc-fault circuit interrupter listed to provide protection to the entire branch circuit a listed arc-fault circuit interrupter, branch/feeder type, or a listed arc-fault circuit interrupter, outlet branch circuit type.  The arc-fault circuit interrupter, outlet branch circuit type, shall be installed at the outlet closest to, and within 3.0 m (10 ft) of the overcurrent device as measured along the branch circuit conductors.

STATEMENT OF PROBLEM AND SUBSTANTIATION FOR PROPOSAL.

The existing requirement at 210.12 covering dwelling unit bedrooms has been modified to include both types of arc-fault circuit interrupters (i.e., branch/feeder type and outlet branch circuit type) that are to be covered by expanded definitions.

Although AFCI devices currently available are incorporated within circuit breakers, AFCI devices have been listed that are incorporated into outlet devices.  While only AFCI/circuit breakers can de-energize the entire branch circuit, listed AFCI/outlet devices can be applied in applications where fuses are provided as the branch circuit overcurrent protection devices.  In addition, listed AFCI/outlet devices have been investigated and listed as an outlet branch circuit type with expanded arc detection capabilities, including sensing certain arcing conditions upstream of the AFCI/outlet device location, and sensing broader arcing conditions downstream of the AFCI/device location.  These safety devices will provide the broadest range of fire protection to the occupants of dwellings.

Mike Holt’s Comment:  I spoke to with William H. King, Jr this week, he’s really a nice guy. He’s trying to push the AFCI Technology via the Code process to do what we all thought it did. He tried to do this for the 2002 NEC, but all of his proposals were rejected. I have not had the time to review Mr.. King’s proposals, once I have, I’ll make a comment.

Copyright © 2002 Mike Holt Enterprises,Inc.
1-888-NEC-CODE (1-888-632-2633)