Hartwell on the Code: The Next NEC - Articles 547-555 (Part 10)
EC-Online, your inside source for NEC information, brings you advance information on what's happening as work begins on the 2002 NEC. Over the next few weeks, we'll tell you what happened at the Hilton Head, S.C. meetings this past January. These results reflect the preliminary votes at the panel meetings, and not the written ballot. Only the written ballot reflects the official panel position. We'll revisit this information after the Technical Correlating Committee meeting. Some results may change at that point. For example, a proposed change in the Code with a code-making panel (CMP) majority short of the required two-thirds will be reported as rejected. Look here for a special report in June on those changes.
What follows is solid, expert analysis from the author's viewpoint that goes beyond a simple recitation of the panel actions. Be sure to get a copy of the NEC Report on Proposals (published in mid July 2000 and available at no charge from NFPA) to see the actual text. NFPA also makes the material available over the Internet when the time comes. In addition, the ROP is merely the first step in creating the next NEC. With its publication, a public comment period opens until October 27 2000, after which the panels reconvene to review their actions. Then the entire record goes before the NFPA membership in May of 2001.
The bottom line? All of the changes covered here may change as the process unfolds, and other proposed changes that were rejected may be accepted after the receipt of comments. Get involved. It's our Code. Look at these articles as good code discussion and a source of assistance if you want to participate in the comment process.
The first article in this 15-part series covered changes in format and style anticipated for the 2002 edition of the NEC. For the remaining six articles, we'll identify the proposed changes by the 2002 location and citation style, with the 1999 NEC location following (if it differs), designated as "Old". That way you'll be able to get a better feel for what to expect in the next NEC.
Part 10, Articles 547—555
- 547.8. This section covers farm distributions fed from a central distribution point, typically a pole top. The panel considerably refined the work begun in the 1999 cycle to write coherent rules that actually reflect current practice on these systems, which have such unique features as feeders without overcurrent protection. The panel action cures a number of problems in the major 1999 NEC initiative in this area, which failed to squarely address the major amendments of Chapter 2 provisions implicit in this arrangement.
The new wording requires a "main" disconnecting means at this point. It then "classifies" this device as the service disconnect for the purposes of code rules, and another provision says that even if the utility happens to provide this switch, if the switch meets these rules it need not be duplicated. This verbal jockeying neatly allows the code to be applied coherently and uniformly, even if this switch falls on the supply side of the service point, which it will in some jurisdictions.
The main disconnect has other unique features. Normally service disconnects have to be readily accessible [230.70(A)], and contain overload protection [230.91] as an integral part (or immediately adjacent). These devices meet neither rule, although they must be operable from a readily accessible point. These issues have been clarified, along with the problem in the 1999 NEC in that they must be listed. Since they don't meet Sec. 230-91 they can't be listed under current standards.
The panel action solved some other problems. Since the feeders that originate from this point have no overcurrent protection, they need special wiring rules to make sure they are wired accordingly. The panel action picked up the clearances in Sec. 230.24(B) along with the building disconnect rules in Article 225 as a step in this direction, but much more needs to be added in the comment period, such as the wiring method restrictions in 230.43. The panel action also corrected the inadvertent result in the 1999 NEC wording, which literally required the farmhouse to be supplied 4-wire. Now the farmhouse (or other buildings as desired can be fed 3-wire, provided the installation meets Sec. 250.32(B)(2) (no parallel grounded conductor return paths through metal piping systems, etc.)
- 547.9. Equipotential planes now clearly apply to outdoor areas, if they contain electrical equipment likely to be energized and accessible to livestock. However, the panel completely removed all language related to voltage gradient ramps. Those will go back to being a design decision.
- Art. 550. Complete rewrite to make the article consistent with the new NFPA 501, which should serve as the new HUD standard. Terminology incorporating manufactured homes, which is the industry preference, has been applied throughout the article. Modifications to Chapters 1 through 4 reflect federal mandates for this industry. The HUD rules supersede state requirements because the enabling federal (US) legislation expressly cited the supremacy clause in the US constitution, with the result that local adoption of the NEC (a state function) cannot prevail over HUD regulations respecting manufactured housing moving in interstate commerce. As the NEC strives toward greater international recognition, however, this type of motivation as the basis for code making panel activity is increasingly questionable.
- 550.11(A) [Old 550-6(a)]. The final paragraph resurrects the old (1987 NEC) allowance for panels to go in a closet, just inside the entry. The substantiating comment referred to closet poles, so this presumably includes clothes closets. There must be 6 in. of space maintained in front of the panel at all times and the door must open 90°. That allowance was struck in the 1990 NEC after compelling substantiation, and has remained out of the Code since. Meanwhile the 30-in. wide/30-in. deep front workspace rule in the second sentence remains undisturbed, which appears to now conflict with the first sentence. In addition, in a separate panel action, panelboards were completely prohibited from bathrooms or clothes closets (echoing the 1999 restriction), but that action occurs in Sec. 550.10(I)(2), which doesn't cover this subject. Clearly, CMP 19 is going to have to revisit this during the comment period.
- 550.12(E) (new). Bathroom receptacles must be on a 20A circuit with no other outlets except the pipe tape outlet, as allowed in the 1999 NEC. Note that the rule doesn't correlate with Sec. 210-11(C)(3) because it makes no provision for other outlets within the same bathroom to be allowed on that branch circuit.
- 550-13(D) [Old 550-8(d)]. Massive reformatting results in subtle, unsubstantiated changes in the receptacle placement provisions. The old rule explicitly stated that appliances (in old Ex. 1) created interrupted spaces on countertops, and established new counter spaces requiring a receptacle if at they were least 12 in. wide. New language, taken from 551.41(B)(1) and 552-41(B)(1), retains the 12-in. rule, but only on either side of the kitchen sink. The new wording also allows a duplex receptacle to count for an "outlet" for both a counter and a refrigerator, which is literally impossible (receptacles are not outlets; they are devices installed at outlets). New list items point to countertops for vanities and "under wall-mounted cabinets," which raises the question of open counters. Items (5) and (6) split apart bar counters and fixed room dividers for no apparent purpose; the bar counter rule loses its dimensional limitation, apparently to correlate with new (G)(4) (more below) but no substantiation offered. {Both (D)(5) and (G)(4) should go back and pick up the old dimension limitation} Item (7) on laundry receptacle location is new, correlating with 210-50(c), and item (8) is the relocation of former 550-8(e). Item (9) is new on bathroom receptacle locations. It incorporates selected language from 210.52, but its provision "above or adjacent to the basin" is different from 210.52(D): "on a wall that is adjacent to the basin".
- 550.19 [Old 550-14]. This is being split into two parts; the first part (A) is what is now in the Code. New (B) covers disconnecting means for expandable or multi-unit homes. There are several errors and questions introduced at this point. An internal cross reference points to 550.5 which no longer exists; if it means the old 550-5, which is now 550.10, which paragraphs in that long section apply? Cords? Are we allowing inter-unit feeders in cord with a receptacle at 50A, etc.? This too needs work in the comment period.
- 551.46(B) 2nd paragraph and 551.77(A). RV sites are due to get a little larger to accommodate expandable room sections. Instead of measuring 9±1 ft from the centerline, now the supply equipment goes 6±1 ft from the driver's side of the parked RV. In addition, for a pull-through site, the supply equipment goes along the same line at any point chosen that is from 16 ft forward of the rear end of the site, to the center of the site measured between the two roadways that provide site access. The allowable length of the supply cord is being increased by 2 ft to accommodate the larger clearance from stand to receptacle.
- Article 555. Article 555 has been totally rewritten, with important technical changes in almost every section. None of the sections line up with the 1999 NEC. This partially implements a realignment of responsibility for electrical installation requirements now covered in NFPA 303 covering marinas and boatyards. After incorporation in Art. 555, they will then be removed from the other document. There are numerous precedents for this in the NEC. Just as Art. 517 controls installation requirements for health care facilities, and Art. 695 similar requirements for fire pumps, this article will cover installation requirements, and the other document will retain the performance, maintenance, and testing provisions. Some of the more important changes follow.
- 555.2 Electrical Datum Plane. (new, covering definitions). The actual definition is complicated, but essentially is that elevation which is two feet above the highest normal water level. This is a critical definition because numerous requirements throughout the article set allowable locations for various items of equipment in terms of specified distances from the datum plane.
- 555.9. (new) Electrical connections must never occur below the datum plane (except for floating piers), and not less than 1 ft above any pier.
- 555.13. This is old Section 555-7 on wiring methods relocated, but extensively amended. It includes express rules on specific cord types and where they are allowed for permanent wiring. New rules on overhead wiring require conductor routing out of possible contact with moving masts and set distances from areas used for raising or lowering masts. Wiring above piers and decks must be rigid steel or rigid nonmetallic conduit, each required to use threaded connections (or, for PVC, threaded terminal adapters). This section also includes former Sec. 555-9, allowing for harbormaster control of wiring over or under navigable waters.
- 555.19. New section on receptacles is far broader than former Section 555-3 it replaces. The first subsection on shore power includes new rules on marine power outlets, as well as required strain relief from the weight and "catenary angle" of the shore power cord, accomplished through specified face angles (illustrated in a new drawing) of the power receptacle or arrangements for separate mechanical methods. The subsection also includes the former Section 555-5 rules on matching branch circuit ratings and the receptacle ratings, which must not be less than 30A. The 1999 NEC allowance for 20A for shorter boats is being discontinued because it has been many years since boats were being manufactured with 20A provisions. Finally, shore power receptacles in the 30A to 50A range must be locking (and grounding), and those for 60A or 100A must be of the pin and sleeve type, the first such express requirement in the NEC.
The other subsection covers receptacles not used for shore power. Receptacles rated 15A and 20A, 125V, must have GFCI protection if located outdoors, in boathouses, and in buildings used for "storage, maintenance, or repair where portable electrical hand tools, electrical diagnostic equipment, or portable lighting equipment are to be used." This last item recalls similar receptacles within automotive repair garages that also require GFCI protection. The new subsection also includes a marking requirement for these receptacles in cases where they occur within marine power outlets, to clearly indicate that they aren't for shore power to boats.
- 550.23 (new). This new section governing marine hoists, railways, cranes and monorails requires such motors to be located above the datum plane. If a trailing cable is needed for power, it needs to be a listed portable power cable suitable for the prevailing conditions, and provided "with an outer jacket of distinctive color for safety."
Acknowledgements
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About the author… (Back to top)
EC Online columnist and nationally recognized NEC expert Fred Hartwell is widely recognized as one of the most prolific contributors to the NEC, with nearly one thousand proposals and comments over the years making it into print. He has three code cycles experience on one of the code making panels. He has many years of contracting experience in Illinois and Massachusetts. He also served as an electrical inspector for fifteen years and he was head electrician on a college campus.