fmtjfw
Senior Member
- Location
- Fairmont, WV, USA
I'm looking for constructive criticism on the following, and if you think it is merited, support in the form of comments from you on 2-92, 2-102, & 2-103. Thanks, Jim Williams
4 Comment:
The numbers enclosed in curly braces are reference points to notes in the substantiation and not intended to be part of the amended text.
red indicates deletion.
revise the text as follows:
210.12 Arc-Fault Circuit-Interrupter Protection.
(A) Dwelling Units.
(1) A listed combination type arc-fault circuit interrupter, installed to provide protection of the entire branch circuit.
(2) A listed outlet branch circuit type arc-fault circuit interrupter installed at the first outlet on the branch circuit where all of the following conditions are met:
a. The branch circuit over current protection device shall be a listed circuit breaker having an instantaneous trip not exceeding {1}300 20 amperes
b. The {2}branch circuit wiring shall be continuous from the branch circuit overcurrent device to the outlet branch circuit arc-fault circuit interrupter.
c. The maximum length of the branch circuit wiring from the branch circuit overcurrent device to the
first outlet shall not exceed 15.2 m (50 ft) for a 14 AWG or 21.3 m (70 ft) for a 12 AWG conductor-.
d. The first outlet box in the branch circuit shall be {3} identified.
(3) A listed outlet branch circuit type arc-fault circuit interrupter installed at the first outlet on the branch circuit where the portion of the branch circuit between the branch-circuit overcurrent device and the first outlet is installed using RMC, IMC, EMT, Type MC, or steel armored Type AC cables meeting the requirements of 250.118 {4} , metal wireways, metal auxiliary gutters, and using metal outlet and junction boxes.
(4) A listed outlet branch circuit type arc-fault circuit interrupter installed at the first outlet on the branch circuit where the portion of the branch circuit between the branch-circuit overcurrent device and the first outlet is installed using a {5} listed metal or nonmetallic conduit or tubing encased in not less than 50 mm (2 in.) of concrete.
{6} Exception No. 1: If RMC, IMC, EMT, Type MC, or steel armored Type AC cables meeting the requirements of 250.118, metal wireways, metal auxiliary gutters, and metal outlet and junction boxes are installed for the portion of the branch circuit between the branch-circuit overcurrent device
and the first outlet, it shall be permitted to install an outlet branch-circuit type AFCI at the first outlet to provide protection for the remaining portion of the branch circuit.
{7} Exception No. 2: Where a listed metal or nonmetallic conduit or tubing or Type MC Cable is encased in not less than 50 mm (2 in.) of concrete for the portion of the branch circuit between the branch-circuit overcurrent device and the first outlet, it shall be permitted to install an outlet branch-circuit type AFCI at the first outlet to provide protection for the remaining portion of the branch circuit.
{8} Exception No. 3:
The last ?conductor-.? in 210.12(A)c. has a dash as a typo and should be removed. Legislative deletion format fails for deleting a dash.
5 Statement of Problem and Substantiation.
{1} 210.12(A) applies to 15- and 20-ampere outlets and devices. Receptacles and lighting circuits would be required to have OCPDs of 15 or 20 ampere ratings. Not even the most extreme motor circuit would allow a 300A OCPD for a 20A FLA. I understand the 300A comes from the theoretical calculation for protection based on the #14 and #12 wire lengths. 90.1(A) Purpose. talks about the practical safeguarding, not the theoretical.
{2} 210.12(A)(2)b. requires ?branch circuit wiring shall be continuous?. I presume, but do not know if that means that the circuit will be without splice. I also assume that continuous does allow pig tailing the grounding conductor in any metallic junction boxes the circuit passes through, but I'm not sure. Or it may mean that it must be in a continuous cable or even in a continuous raceway (ENT perhaps). This need to be clarified. Possible text could be ?wiring shall be continuous unspliced from? or ? wiring shall be in a continuous sheath or wiring method from? depending on the meaning intended.
{3} 210.12(A)(2)d. requires the first outlet box to be identified. This is the only box in the entire text for 210.12 that has that requirement. Is this box somehow special? Is identified missing from the other box references?
Since 210.12(A)(2) specifies no wiring methods, I presume that all wiring methods are allowed.
{4} 210.12(A)(3) requires the use of RMC, IMC, EMT, Type MC, or steel armored type AC meeting the requirements of 250.118. Exception 1 merely adds ?metal wireways, metal auxiliary gutters,? without imposing any additional requirements. Folding exception 1 into 210.12(A)(3) imposes the same rules without the added text.
{5} 210.12(A)(4) allows the use of nonmetallic conduit if encased in 2 in. of concrete. The listing ?metallic or? is unnecessary since 210.12(A)(3) already allows that whether or not it is encased in concrete.
{6} With the addition of the phrase in {4} above Exception No. 1 is now completely redundant and can be eliminated.
{7} Exception No. 2: allows the use of metal or nonmetallic conduit or tubing encased in 2 in. of concrete. This is already allowed in 210.12(A)(3) and (A)(4), as amended. Exception No. 2: also allows MC cable to be used if encased in 2 in. of concrete, but 210.12(A)(3) already allows that. Thus Exception 3 is now completely redundant and can be eliminated.
{8} Exception No. 3: is now the only exception left standing and now can be renamed ?Exception:?
The exception text appears to reflect the piling of ROPs on this section.
4 Comment:
The numbers enclosed in curly braces are reference points to notes in the substantiation and not intended to be part of the amended text.
red indicates deletion.
revise the text as follows:
210.12 Arc-Fault Circuit-Interrupter Protection.
(A) Dwelling Units.
(1) A listed combination type arc-fault circuit interrupter, installed to provide protection of the entire branch circuit.
(2) A listed outlet branch circuit type arc-fault circuit interrupter installed at the first outlet on the branch circuit where all of the following conditions are met:
a. The branch circuit over current protection device shall be a listed circuit breaker having an instantaneous trip not exceeding {1}300 20 amperes
b. The {2}branch circuit wiring shall be continuous from the branch circuit overcurrent device to the outlet branch circuit arc-fault circuit interrupter.
c. The maximum length of the branch circuit wiring from the branch circuit overcurrent device to the
first outlet shall not exceed 15.2 m (50 ft) for a 14 AWG or 21.3 m (70 ft) for a 12 AWG conductor-.
d. The first outlet box in the branch circuit shall be {3} identified.
(3) A listed outlet branch circuit type arc-fault circuit interrupter installed at the first outlet on the branch circuit where the portion of the branch circuit between the branch-circuit overcurrent device and the first outlet is installed using RMC, IMC, EMT, Type MC, or steel armored Type AC cables meeting the requirements of 250.118 {4} , metal wireways, metal auxiliary gutters, and using metal outlet and junction boxes.
(4) A listed outlet branch circuit type arc-fault circuit interrupter installed at the first outlet on the branch circuit where the portion of the branch circuit between the branch-circuit overcurrent device and the first outlet is installed using a {5} listed metal or nonmetallic conduit or tubing encased in not less than 50 mm (2 in.) of concrete.
{6} Exception No. 1: If RMC, IMC, EMT, Type MC, or steel armored Type AC cables meeting the requirements of 250.118, metal wireways, metal auxiliary gutters, and metal outlet and junction boxes are installed for the portion of the branch circuit between the branch-circuit overcurrent device
and the first outlet, it shall be permitted to install an outlet branch-circuit type AFCI at the first outlet to provide protection for the remaining portion of the branch circuit.
{7} Exception No. 2: Where a listed metal or nonmetallic conduit or tubing or Type MC Cable is encased in not less than 50 mm (2 in.) of concrete for the portion of the branch circuit between the branch-circuit overcurrent device and the first outlet, it shall be permitted to install an outlet branch-circuit type AFCI at the first outlet to provide protection for the remaining portion of the branch circuit.
{8} Exception No. 3:
The last ?conductor-.? in 210.12(A)c. has a dash as a typo and should be removed. Legislative deletion format fails for deleting a dash.
5 Statement of Problem and Substantiation.
{1} 210.12(A) applies to 15- and 20-ampere outlets and devices. Receptacles and lighting circuits would be required to have OCPDs of 15 or 20 ampere ratings. Not even the most extreme motor circuit would allow a 300A OCPD for a 20A FLA. I understand the 300A comes from the theoretical calculation for protection based on the #14 and #12 wire lengths. 90.1(A) Purpose. talks about the practical safeguarding, not the theoretical.
{2} 210.12(A)(2)b. requires ?branch circuit wiring shall be continuous?. I presume, but do not know if that means that the circuit will be without splice. I also assume that continuous does allow pig tailing the grounding conductor in any metallic junction boxes the circuit passes through, but I'm not sure. Or it may mean that it must be in a continuous cable or even in a continuous raceway (ENT perhaps). This need to be clarified. Possible text could be ?wiring shall be continuous unspliced from? or ? wiring shall be in a continuous sheath or wiring method from? depending on the meaning intended.
{3} 210.12(A)(2)d. requires the first outlet box to be identified. This is the only box in the entire text for 210.12 that has that requirement. Is this box somehow special? Is identified missing from the other box references?
Since 210.12(A)(2) specifies no wiring methods, I presume that all wiring methods are allowed.
{4} 210.12(A)(3) requires the use of RMC, IMC, EMT, Type MC, or steel armored type AC meeting the requirements of 250.118. Exception 1 merely adds ?metal wireways, metal auxiliary gutters,? without imposing any additional requirements. Folding exception 1 into 210.12(A)(3) imposes the same rules without the added text.
{5} 210.12(A)(4) allows the use of nonmetallic conduit if encased in 2 in. of concrete. The listing ?metallic or? is unnecessary since 210.12(A)(3) already allows that whether or not it is encased in concrete.
{6} With the addition of the phrase in {4} above Exception No. 1 is now completely redundant and can be eliminated.
{7} Exception No. 2: allows the use of metal or nonmetallic conduit or tubing encased in 2 in. of concrete. This is already allowed in 210.12(A)(3) and (A)(4), as amended. Exception No. 2: also allows MC cable to be used if encased in 2 in. of concrete, but 210.12(A)(3) already allows that. Thus Exception 3 is now completely redundant and can be eliminated.
{8} Exception No. 3: is now the only exception left standing and now can be renamed ?Exception:?
The exception text appears to reflect the piling of ROPs on this section.