Question 1. I am an inspector member with a question about interpretation of code regarding MC. We have been told that MC and AC run through metal studs require insulating bushings or grommets which stay in place after installation before pulling cables. The explanation we received involved reference to 300.4 Were we informed correctly? — R.K. Answer 1. My response will be as indicated in the 2002 NEC; the reference stated is partially correct but the answer lies in Section 300.4(B)(1) that only addresses nonmetallic-sheathed cable. Thus, grommets are not required for the installation of Type MC, metal-clad cable as covered under Article 300 or for Type AC, armored cable as covered under Article 320 for installation through metal framing members. Section 300.4(B)(1) specifically states nonmetallic-sheathed cable and does not mention Type MC or AC cable wiring methods. Section 300.4(B)(2) specifically addresses nonmetallic-sheathed cable (NM) and electrical non-metallic tubing (ENT) where nails or screws are likely to penetrate and are then to have additional protection via a steel sleeve, sleeve plate, or steel clip as a protective measure. But once again, the Code does not mention Type MC or AC cable wiring methods in need of the same requirement. In my opinion, the confusion lies back in the cable articles, such as 320.17 for AC cable and 330.17 for MC cable, which are titled, Through or Parallel to Framing Members, the wiring methods shall be protected in accordance with 300.4 where so installed. Therefore, 300.4(A) would apply, 300.4(C) would apply, 300.4(D) would apply, and 300.4(E) would apply; however, the part that would not apply to those type wiring methods are 300.4(B) for the reason stated previously and 300.4(F) since that applies to raceway type wiring methods. If we examine the Code a little further and look at the language of 320.23(B) for Type AC Cable in accessible attics, it clearly indicates that 300.4(D) shall be complied with and adhered to. Then as we look at the Type MC cable article, under Section 330.23 with the similar type protection requirement, it refers back to complying with 320.23 as stated above. When a review of the Code is made, many times we have to go back and forth between various articles and follow the path to get the correct answer. When CMP-3 discussed that concern for additional protection for nonmetallic-sheathed as indicated in 300.4(B), the debate also considered the need to include Type MC and AC as well. But field information and results of other fact-finding reports concerning nail penetration did not justify the call for it. Electrical safety is the top priority for all segments of the electrical industry and I applaud the steps taken by the various code panels and the Technical Correlating Committee to realign the cable and raceway articles for similar requisite sequencing for all, thus making it easier to cross reference the requirements. The better the end user of the Code and the inspection departments can review the Code and come to a correct answer to the question, the more everyone benefits. — Raymond W. Weber, CMP-3 Chair | Return to top | Question 2. Can a receptacle be on both sides of the wall, that is, in the same wall stud cavity in the garage and on the opposite side of the wall in the house? I read somewhere that such an installation is a fire-wall problem. — T. B. Answer 2. The NEC reference would be 300.21. This section states that openings around penetrations through fire-resistant-rated walls shall be firestopped using approved methods to maintain the fire-resistance rating. A FPN then refers to directories of testing laboratories, such as the UL Blue book, which covers building materials and assemblies. The FPN also specifically refers as an example to the 24-inch horizontal separation required on opposite sides of a fire-rated wall. You then need to go to the building code adopted by your jurisdiction to determine: 1. If the separation between the attached garage is, in fact, a required fire separation. In most building codes such as the Uniform Building Code, International Residential Code, or International Building Code it is required. 2. What methods your building code will allow for penetrations on both  sides of a fire-rated assembly. (Assuming, again, it is required by the local building code.)  Some possible methods allowed by the building codes listed above would be:   1. Steel electrical boxes not exceeding 16 square inches in volume, installed in opposite sides of the wall and separated by a horizontal distance of not less than 24 inches. 2. By a horizontal distance of not less than the depth of the wall cavity, if the cavity is filled with cellulose insulation or mineral-fiber insulation. 3. Other boxes listed for use in fire-rated assemblies and installed in accordance with the manufacturer's installation instructions. Remember, the building code requirements above are general in nature and subject to modification or deletion by the local building authority. – Richard Owen, CMP-3 chair | Return to top | Question 3. This question is regarding the use of an eagle blank face to provide GFCI protection. What code violations, if any, exist when you place a blank face GFCI device near a panel, connect the line side to a regular circuit breaker, and let the load side serve to protect the outlets that are required to be GFCI protected? Should the required GFCI device be located in the panel? — M.J. Answer 3. The device or protection technique is not mandated to be installed in the panelboard; but if a GFCI breaker is used this is certainly allowed and permitted. I do not see a problem with this application or utilization of that type of device. As we review the requirements of 210-8(a) [NEC 1999] and 210.8(A) [NEC 2002], both are the same and state: “Dwelling Units. All 125-volt, single-phase, 15- and 20-ampere receptacles installed in the locations specified below shall have ground-fault circuit-interrupter protection for personnel.” The section does not specify any certain type to be used; it could be breaker in the panel; a GFCI-protected receptacle as the first device in the circuit; or, as you show and indicate, a “blank face GFCI protective device” next to the panelboard or in the circuit prior to any loads or receptacle installed, which is acceptable. The only problem is, after you step out of the shower and plug in your blow comb and the device trips for some reason, you may get cold feet walking over to the panelboard location to reset it. I commonly see this type of device used with 120-volt supplies to spas, hot tubs, or hydromassage bathtubs per 680-70 [NEC 1999] or 680.71 [NEC 2002], and installed on a wall adjacent to its location; if it does trip off for some reason, it can be easily reset without removing access points or panel covering to get to the hidden GFCI protector. To give a direct answer to your question, I do not see a problem with the use of this GFCI protection as you have presented it. — R.W. Weber, CMP-3 | Return to top | Question 4. We have had confusion regarding 210.11(C)(3), Exception, and 210.23(A), Exception. Can a bath light/fan and other light fixture(s) be on the 20-A, GFCI receptacle circuit if it feeds only a single bath room? Is there anything else to know about 210.11 and 210.23? — B.S. Answer 4. The question is being answered with the 2002 NEC as a guide document. The exact words of Section 210.11(C)(3), Exception, are as follows: "Where the 20-ampere circuit supplies a single bathroom, outlets for other equipment within the same bathroom shall be permitted to be supplied in accordance with 210.23(A)."The base rule of 210.11, Branch Circuits Required, (C) Dwelling Units, (3) Bathroom Branch Circuits states, "In addition to the number of branch circuits required by other parts of this section, at least one 20-ampere branch circuit shall be provided to supply the bathroom receptacle outlet(s). Such circuit shall have no other outlets. "Thus if you have a dwelling unit with three bathrooms on the same floor level or one or two other floor levels, you can take one 20-ampere branch circuit and feed the GFCI [210.8(A)(1)] protected receptacles in each one on that single circuit. But it is not to have any other outlet(s), meaning other than receptacles on it.With that said and under our first scenario you could have a receptacle in each of the three bathrooms or more in all three provided that you do not have any light outlets, fan units or other loads on that circuit. But what the exception, as was restated above, allows you to do if you choose and have enough branch circuit spaces available in the panelboard is to take one 20-ampere branch circuit to a bathroom; or if you have more than one bathroom in the dwelling, you can take a separate 20-ampere branch circuit to each bathroom location and then since it only serves that one room, you can have other outlets or have other equipment on that same circuit. Perhaps now is a good time to review the definition of outlet per Article 100 which states: "Outlet. A point on the wiring system at which current is taken to supply utilization equipment." This could be a light or fan unit or combination of both or a smoke detector if you chose to put one in the bathroom area. Possibly even a motor to a hydromassage tub unit depending on its size. Remember under the exception, it stated, "to be supplied in accordance with" and we were directed to 210.23(A). With 210.23 being Permissible Loads and (A), being 15- and 20-ampere Branch Circuits, the requirement then indicates "a 15- or 20-ampere branch circuit shall be permitted to supply lighting units or other utilization equipment, or a combination of both, and shall comply with 210.23(A)(1) and (A)(2)." Then(A)(1) states that "The rating of any one cord-and-plug-connected utilization equipment shall not exceed 80 percent of the branch-circuit ampere rating." (A)(2) follow with, "The total rating of utilization equipment fastened in place, other than luminaires (lighting fixtures), shall not exceed 50 percent of the branch-circuit ampere rating where lighting units, cord-and-plug-connected utilization equipment not fastened in place, or both, are also supplied."Under (A)(1) and with a 20-ampere circuit at 80 percent, you cannot have a cord-and-plug-connected piece of utilization equipment with a load greater than 16 amperes. As well under (A)(2) the total fastened in place utilization equipment cannot exceed 50 percent of the branch circuit ampere rating; or with a 20-ampere circuit have more than 10 amperes supplying that fixed piece of equipment and have lights or cord-and-plug equipment on that same circuit. Oftentimes what we see are baths with a hydro-massage bathtub and a connection made to that circuit, which puts the motor at a single-phase 120-volt, 1/2-hp motor or smaller. If the hydromassage tub has a ¾-hp motor or larger, then a separate circuit would be required; and oftentimes the listing by the manufacturer or nationally recognized testing laboratory and its labeling may require a separate circuit and not allow it to be fed by the single 20-ampere circuit going to the bathroom. In conclusion, the question as asked indicates "can a bath light/fan unit (fixed piece of utilization equipment, non-cord-and-plug connected utilization equipment) and other light fixtures be on a single 20-ampere GFCI circuit if it feeds only a single bathroom." The answer is yes provided the "bath light/fan unit" does not exceed the 50 percent requirement at 10 amperes on a 20-ampere branch circuit. The important thing to remember is that 210.11 addresses branch circuits required and (3) covers bathroom branch circuits. Whereas 210.23 addresses permissible loads and the two sections are cross-referenced. I am a firm believer in the more circuits the better and lightly load them because we all know that future electrical loads will be added and oftentimes are not planned for. — Ray Weber, CMP-3 | Return to top | Question 5. In the July/August 2004, "Focus on the Code," a question was asked regarding 210.11(C)(3), 210.11(C)(3) Exception, and 210.23(A) Exception. Ray Weber’s comment was well written and correct for the most part. In the answer Mr. Weber stated that a single 20-ampere branch circuit could supply an unlimited number of receptacle outlets in an unlimited number of bathrooms. It is my opinion that this is not correct and not the intent of the original proposal when the article was revised. In a small dwelling, perhaps this would be okay. If you look at our modern dwellings being built today, they are enormous in size and have multiple bathrooms. The original intent of the code change was to limit the load on the bathroom receptacle due to the use of hair dryers, curling irons, curler heaters, etc. In the more modern dwellings there may be five to six or more bathrooms and half baths.The language in 210.11(C)(3) states, "at least one 20-ampere branch circuit shall be provided to supply the bathroom receptacle outlet(s)." The word bathroom is singular and does not indicate that it may be both singular and plural, as does outlet(s). It is my opinion that the 20-ampere branch circuit is intended for the receptacle outlet(s) in a single bathroom only, not multiple receptacle outlet(s) in multiple bathrooms. —L.J. Answer 5. I understand this gentleman’s viewpoint and position; however, I do not agree and I remain steadfast on my comments and answer to the question. However, this does reinforce the fact that the written word is subject to interpretation and we as an organization, the IAEI, need to remain in the forefront of not only being involved in writing the Code but also in teaching and clarifying the meaning of the various sections for our members. It has been said that differences of opinion created the need for horse races; likewise, the Code is open to others to make their viewpoints known in subsequent Code change proposals and, then, to let the process confirm or deny the validity of those points. —Ray Weber, CMP-3 | Return to top | Question 6. In the 1999 NEC Handbook, Figure 210.28 on page 87 shows three one-family dwellings. This figure shows row housing with GFCI-protected receptacles. What is the difference between row housing and multi-family dwelling (triplex)?. — T.T. Answer 6. As we view the noted diagram, three living units are depicted with the indication of firewalls between the middle unit and the common walls of the units on either side but not as outside walls of that unit or the adjoining units. Thus, they are three individual units with a fire rated assembly separation and each would have equal status of an individual dwelling unit.  Some may address it as a zero based lot line concept of construction and any number of units could be so attached.  As to the difference between row housing and multifamily dwelling units, the answer lies in the type of firewall assemblies installed between dwelling units. Normally to attain the row house status, this firewall must be install from the lowest floor level (basement floor elevation in a multi-story configuration; or for slab-on-grade construction, the concrete floor level) and the fire rated construction extends upwards to the underneath side of the of the roof covering.  Thus, the attic spaces between adjoining units have the same type of separation as the occupied spaces.   In a multifamily dwelling, that type of fire separation is not installed between the individual dwelling units; only the exterior framing is considered for the fire rating given the building height, location and number of units involved and common hall ways and stairways.  The question addresses the need for GFCI-protected receptacles, which is true both front and back of each unit.  The larger question usually is in regards to the number of services allowed for such row-house-type units since it appears as one building has multiple segments. Some jurisdictions offer the following solution to the one service rule: "For a building which is not more than three stories in height and which contains only 3 or more attached, vertically separated, side-by-side or back-to-back dwelling units, with each dwelling unit served by an individual exterior exit within 6 feet of the exit discharge grade, a separate service drop or lateral shall be permitted for each two attached units.”  The italicized phrases are added for emphasis, and depict the unique nature of that type of construction and deviation from the one service rule.  The local building official should be consulted as to how the structure is viewed for meeting the building service allocation requirements.  In summary, there is a difference between those two types of occupancies and even though some may view them as one building and others may view them as separate buildings, the requirement for GFCI- protected receptacles in both front and back of the row house unit still are needed. — Raymond W. Weber, CMP-3 | Return to top | Question 7. I find a conflict in the NEC. Section 300.22(B) indicates that all wiring in duct ors or plenums for environmental air must use Type MI or MC or be in conduit. Section 300.22(C) says MI, MC, AC, or other factory assembled cable listed for the use. Section 725.71(A) lists CL2P and CL3P as being suitable for use in ducts, plenums, and other space used for environmental air. If I cannot use PLENUM cable without putting it in conduit, why would I spend three times as much for it as for CL2?  — A.D. Answer 7. I think the answer is in Section 90.3, which says that "Chapters 1 through 4 apply except as amended by Chapters 5, 6, and 7 for the particular conditions." This means that the specific rule in 725.71(A) modifies and overrules the general rule in 300.22. Thus listed, plenum-rated cable is allowed without installing it in a raceway.  — Richard Owen, CMP-3 | Return to top | Question 8.The electrical enclosures installed in food processing plants and, especially, meat and poultry processing facilities are subjected to daily wash downs and hot/cold thermal changes, which create condensation in the conduits as well as enclosures.  What are the recommendations for conduit routing and entry into electrical enclosures, as well as any other standards that address the best practices to keep water and condensate out of the enclosures? — J.K. Answer 8. First of all, 90.1(C) indicates that the Code is not intended as a design specification, and there is very little information in the NEC about drainage of raceway systems or boxes/enclosures. One such requirement is found in Section 230.53, and all that says is the raceway shall be “arranged to drain.” Common sense would indicate the low spots should have a drain (if this is as big a problem as you indicated) and it wouldn’t be wise to have a raceway enter an enclosure over the top of electrical equipment so the condensation would drip onto it. The National Electrical Contractors Association (NECA) has developed some installation standards, which are advisory only, and the steel raceway manufacturers may have other guidelines, but as I mentioned before, this is a design/installation concern.  — Richard P. Owen, CMP-3 (September/October 2006) | Return to top | Question 9. In NEC-2005, Article 100, Definitions, look at the terms Location, Damp and Location, Wet. Local electricians question the intent of the Code when it comes to classifying the location of raceways (commonly non-metallic) located in an interior concrete slab. The most common example is a raceway from an interior wall to an island location in a residence.  It appears that strict interpretation would classify this as a wet location and require suitable conductors because the raceway is “in a concrete slab” that is “in direct contact with the earth.” The electricians argue that it seems reasonable that this could be considered a damp location and thus allow the use of THHN conductors (NM cable). Is the intent of the Code to include such locations under the definition of Location, Wet? — S.C. Answer 9. The definition of Location, Wet very specifically classifies a raceway in a slab in direct contact with the earth as a wet location. So, unless your AHJ wants to take a different view of this, I think it’s pretty clear. Another problem with the scenario you described of using NM cable (assuming the cable is installed in a raceway in the slab) is that 334.10(A) states that NM cable shall be permitted only in normally dry locations, so even if the raceway in the ground-level slab would be considered damp rather than wet, the sheath of NM cable is not approved for either location. — Richard Owen, CMP-3 (November/December 2006) | Return to top | Question 10. I am an electrical instructor at a 2-year trade school.  My question is based on Section 527.6(A) of the NEC-2002.  It states that, “For the purposes of this section, cord sets or devices incorporating listed ground-fault circuit interrupter protection for personnel identified for portable use shall be permitted.”  Does this mean that a temporary pole, installed on a construction site with no permanent buildings present, is not required to have circuit breakers or receptacles that are GFCI type provided that a UL listed GFCI cord set is used be suffice to protect personnel?  In other words, is it mandatory that circuit breakers or receptacles be of the GFCI type at this location? — P. P. Answer 10. The basic rule in 527.6(A) is that all 125-volt, single-phase, 15-, 20- and 30-ampere receptacles that are installed as part of the temporary installation shall have GFCI protection through either a GFCI receptacle or breaker. These are normally part of a temporary electrical service supplying power for construction. As a building is finished, it becomes much more difficult to run cords from the temporary service location, so most electrical contractors will start “heating up” the permanent receptacle circuits within the building. This is when the portable GFCI comes into service, since if even a permanently-installed receptacle is used for construction power, it must be GFCI-protected. It is not feasible to require that the permanently-installed receptacles be GFCI-protected until the construction is completed, so the section allows the use of the portable GFCI cordsets for these receptacles. Also, from my experience with OSHA, they want the portable GFCI to be at the receptacle, not on the end of any extension cord, so that the cord is also protected by the ground fault. This part is not in the NEC, but at least in my part of the country this is how OSHA is enforcing it.   — Richard Owen, CMP-3 (January/February 2007) | Return to top | Question 11. When reading 725.3 and 725.51, does 725.3 tell me that even though 725.51 includes chapter one of the NEC, work space for class 2 equipment is not required? — J. G. Answer 11. The mandatory requirements in 725.3 and 725.51 depend upon when the working spaces in 110.26 are required to be enforced about Class 2 equipment and when they are not required to be enforced.  According to 90.3, Code Arrangement, chapters 1 through 4 apply generally throughout the National Electrical Code and the requirements in Article 725 supplement or modify the general rules for this particular or special condition. Article 725 exclusively “covers remote-control, signaling, and power-limited circuits that are not an integral part of a device or appliance.”  725.1 FPN states, “The circuits described herein are characterized by usage and electrical power limitations that differentiate them from electric light and power circuits; therefore, alternative requirements to those of Chapter 1 through 4 are given with regard to minimum wire sizes, derating factors, overcurrent protection, insulation requirements and wiring methods and materials.” The mandatory supplements or modifications to the general rules in Article 725 are listed in 725.3, Other articles, by stating “Circuits and equipment shall comply with the articles and sections listed 725.3 (A) through (G).” The requirements for working spaces in 110.26 are not included in the list and, therefore, are not required to be maintained around Class 2 equipment. However, 725.51, Wiring Methods on Supply Side of the Class 2 and Class 3 Power Source states, “Conductors and equipment on the supply side of the power source shall be installed in accordance with the appropriate requirements of Chapters 1 through 4.  Transformers or other devices supplied from electric light or power circuits shall be protected by an overcurrent device rated not over 20-amperes.” This requires any lighting or power circuit with associated fittings and enclosures supplying Class 2 (or 3) equipment to have proper working clearances about them per 110.26, and would include the Class 2 (or 3) equipment by proximity. Once the Class 2 conductors and equipment are isolated from the power source circuits, the requirements revert to 725.3 (A) through (G) and the working spaces in 110.26 are not required to be maintained about Class 2 (or Class 3) equipment. — Robert Walsh, CMP-3 (November/December 2007) | Return to top | The views of the authors of Focus on the Code and the editor are provided solely as a public service.  The views expressed are not the official position of NFPA, the NEC Correlating Committee or any of its panels, IAEI, IAEI News, or the author's employers. Nor are they intended to represent a formal or informal interpretation of the NEC.

Home  | Join | Advertising | Seminars | Contact Us | Privacy Statement | Legal Notices
Copyright © 1997-2008 IAEI. All Rights Reserved.