A new NEC is on tap, with major changes in how the document presents the material, even changing to a new full-page format.
This analysis of the changes represented in the 1999 edition of the National Electrical Code (NEC) covers the most significant of the many changes. Some are indeed major, including two new articles (with another article deleted). Others involve only minor editorial issues. Major or minor, if you are involved with the particular subject matter, the most minor changes can assume major proportions in unexpected ways. Every proposal was made for a reason, and this magazine article is no substitute for careful study of the Code itself.
Sec. 680-6(a)(1). The allowance for a GFCI-protected twist-lock receptacle located as close as 5 ft to a pool for a water pump now also includes other loads related to the circulation and sanitation system.
This allows you to locate such items as ozone generators next to the recirculation pump. This was an exception, but is now reformatted as positive text. In the process, we now have a 77-word run-on sentence that is nearly impossible to read. However, if you look at it long enough, you'll find the elements of this change.
Sec. 680-6(a)(2); similar change in Sec. 680-41(a). The dwelling-unit convenience receptacle adjacent to pools must be a 125V 15A or 20A receptacle on a general-purpose branch circuit.
This section never said what kind of receptacle you need to install, as long as it was 125V. Now, the AHJ has enforceable language as to what form it must take. Literally allowed in the prior Code, a 125V 30A receptacle doesn't serve the intended purpose.
Sec. 680-6(d). A new subsection requires wiring supplying single-phase 125V or 240V pool pump motors rated 15A or 20A in other than dwelling units must have GFCI protection, whether cord or directly connected.
The literal text requires "wiring supplying pool pump motors rated 15A or 20A, 125V or 240V, single phase ..." The drawing (above) shows a 2-hp 240V pump motor (Table 430-148 rating: 12A). It is supplied from a 30A inverse-time circuit breaker. This breaker complies with Sec. 430-52(c)(1), and the wire is No. 14 THWN, per Sec. 430-22(a) (wire rating: 20A under the conditions of use, and 600V insulation rating.) Check with the AHJ on whether this circuit requires GFCI protection. Sec. 210-3 sets the overcurrent protective device rating as the circuit rating, but this is a motor circuit, beyond the scope of Art. 210. We think the circuit protection should be the benchmark, and the result would be no mandated GFCI protection in this case. Nevertheless, this wording is a classic.
We haven't addressed the merits of only imposing this rule on nondwelling occupancies. Don't ask. We're just telling you how the Code changed.
Sec. 680-12. This section now requires you to provide a disconnecting means, as well as simply assuring it be accessible (if provided).
This corrects a major error in the 1996 NEC. Note: The requirement applies to all pool equipment, which literally includes lighting.
Sec. 680-22(a)(1). If reinforcing steel is effectively insulated by a listed encapsulating compound at the time of manufacture and installation, you don't need to bond it.
If you're confronted with epoxy-coated reinforcing bar (commonly supplied for corrosion resistance), you're only supposed to omit bonding in cases where the steel foundry that rolled the bar stock went out and had the epoxy coating listed. Some pools involve literally thousands of reinforcing members; every single one of which use epoxy coating, even the tie wires.
Remember, even if you do grind off the coating to make connections, the construction specifications normally require repainting with epoxy so as not to defeat the purpose of ordering the epoxy coating in the first place.
EC&M tip: If enforced, this rule will make any such job prohibitive. Be sure you sort this out with the inspector before you bid a pool job using epoxy-coated reinforcing. We seriously doubt any such reinforcing will ever be submitted for listing.
Sec. 680-25(b)(3) Ex. A new exception allows you to use liquidtight flexible conduits (metallic or nonmetallic) up to 6 ft long in one piece, or at multiple points with up to 10 ft total, to connect pool-light transformers.
This exception isn't located properly. It follows (3), which is a permissive allowance for use of EMT or ENT in or on buildings. It should probably follow (2), but you'll need to discuss this with the inspector. The objective is to provide flexibility in the wiring methods at the transformers, so you can take them out for service or replacement more easily.
Sec. 680-25(d). This section, which addresses panels supplied from separately derived systems for the first time, requires a grounding conductor based on Table 250-66 for grounding electrode conductors. The '99 NEC broadens the rules slightly to address a disconnecting means as well as a panelboard. As in the case of underwater lights, the Code adds liquidtight flexible nonmetallic conduit as an acceptable wiring method. A fourth change involves ENT, which you can now use for the first time, but only within buildings.
This change recognizes these panelboards often end up in a cabana or other building with a Sec. 225-31 disconnecting means. Be careful with separately derived systems. The literal text requires the grounding conductor to extend from the panelboard, upstream of the separately derived system disconnecting means, and all the way back to the source of the separately derived system. If the separately derived system is a transformer, per Sec. 250-30(a)(1), this will usually drag the main bonding jumper back with it to the transformer wiring compartment. Finally (given the Table 250-66 reference) the grounding conductor could end up larger than the circuit conductors in some cases.
Sec. 680-25(d)(2). You can install the special equipment grounding rules for panelboards in cases where the feeder meets the grounding rules in Sec. 250-32. If you install an equipment grounding conductor, however, it needs to be an insulated conductor.
If there are no common metallic parallel paths between buildings, this will allow the equipment grounding path to be over a regrounded neutral. Remember: There is always a voltage to ground on these conductors. As such, you'll have to constantly impose a voltage on the pool bonding grid in those cases where there is an equipment grounding connection to that grid. Fortunately, the changes in Sec. 250-32 make regrounded neutrals less likely.
Sec. 680-38. A new section requires all spas and hot tubs, except those in single-family dwellings, to have a clearly labeled emergency shutoff or control switch, readily accessible to the users. It must be adjacent to and within sight of the spa or hot tub, but at least 5 ft away. The control, which can be similar to an emergency stop button, must stop the motor(s) providing power to the recirculation system and jet system.
Background: This follows a tragedy in New Jersey where a teenaged girl was sucked up tight to a broken intake grille and couldn't free herself. Her friends, including several football players, couldn't break the suction either. She drowned while they tried frantically to shut the motor off. There was a disconnect, and it was in sight of the spa. However, it was under the platform behind a locked door, accessible only to maintenance personnel.
This change assures user access to an appropriate control device. It isn't an across-the-line disconnecting device necessarily, although it could be. Note the real solution involves the design and maintenance of intake grilles. The CPSC and UL are very far along with that work.
Sec. 680-41(a)(1); similar change in Sec. 680-70. You now measure the minimum dimension to receptacles horizontally.
Suppose you have an adjacent receptacle located at a higher level and 5 ft distance (measured along a diagonal) or even 5 ft directly above the tub. Both scenarios were previously acceptable. Now, neither one qualifies as an acceptable placement.
Sec. 680-42. A field-assembled spa or hot tub with a heater load of 50A or less must now have GFCI protection. The prior rule only applied to packaged or self-contained units. Field-assembled units that are three-phase or rated over 250V don't require GFCI protection. In addition, units in combination with a pool and share the same bonding grid do not require GFCI protection.
This change begins to rectify an anomaly, where the listed units labor had the complete GFCI restriction, while the field-assembled units had none. As worded, there isn't any requirement to subdivide higher rated heating loads and then impose the restriction on all circuits. The factory-assembled ones do that now; why not field-assembled ones?
Sec. 680-57. A new section addresses signs placed in fountains. Any circuits supplying the sign require GFCI protection. Any sign installed within a fountain must be set back at least 5 ft from the outside edge.
There is a bonding requirement that refers to Sec. 600-7. This section was supposed to have a requirement to bond the metal parts of a sign and its equipment grounding conductors to the equipment grounding conductor of the fountain. CMP 18 lost this change while making other changes in Sec. 600-7 during the comment period, because the panel forgot it previously accepted it. Therefore, this reference no longer means anything. Nevertheless, there's certainly no reason not to make the connection. The problem undoubtedly will be fixed in the next Code.
Sec. 680-62(a). The '99 NEC refines GFCI protection rules for therapeutic tubs and hydrotherapeutic tanks. A self-contained or packaged unit must have GFCI protection, along with field-assembled units with a heater load of 50A or less. Field-assembled units with higher heating loads, those that are three-phase, or those rated over 250V don't require GFCI protection.
This is similar to the change in Sec. 680-42 for spas and hot tubs.
Sec. 680-72. This new section, for hydromassage bathtub equipment, requires accessibility without damaging the building structure or finish.
This has been an ongoing problem. One example is when the tub ends up set in a completely tiled tub base. However, the requirement merely repeats the accessibility requirements in Sec. 110-26 and adds nothing to the Code.
Sec. 680-73. This new section requires bonding of the pump motor to the associated metal parts of electrical equipment and the piping system, if metal. The bonding conductor must be copper and not smaller than No. 8 solid.
This equipment is always produced with a bonding lug to accommodate local bonding requirements, with the exception of double-insulated (DI) equipment. You must not bond DI equipment because it will lose its essential DI characteristics. The final version of the rule takes this into account.
Sec. 690-10. This is an entirely new section providing rules on how to address stand-alone systems you might connect to a service subsequently.
The wiring on the load side of the building or structure disconnecting means must meet all relevant Code requirements (e.g., 100A service equipment for a house).
The AC inverter, however, can supply power to that disconnecting means over conductors that simply reflect the rating of that inverter. However, you must install an overcurrent device responsive to the ampacity of those supply conductors at the output of the inverter.
If those conductors originate at a single 120V supply, they may run to 120V/240V distribution equipment, with the ungrounded conductor arranged to feed both line buses. There must be no multiwire branch circuits and no 240V connected loads. Also, the overcurrent device at the inverter must not exceed the neutral bus rating in the panel. You also must mark the equipment with a warning against connecting multiwire branch circuits.
This is a very reasonable approach to buildings located in extremely remote areas with no utility grid within miles. You wire as though there were going to be a utility service, and then connect whatever power is available. The rule assures that when (and if) a service does arrive, the installer has not taken unsafe shortcuts that might be costly (and therefore resisted) to undo at that time.
Art. 695. The article is completely rewritten. Only the scope (Sec. 695-1) is essentially unchanged.
Note on campus-style distributions: The switching and feeder arrangements required to provide a power source on a campus distribution, which is comparable in reliability to a straight utility service connection, involve complex engineering beyond the scope of this article. Please refer to the Engineer's edition of EC&M's 1999 Illustrated Changes book for a detailed analysis including numerous one-line diagrams. In particular, you'll need this information to properly apply Sec. 695-3(b), Sec. 695-5(c), and Sec. 695-6.
Sec. 695-3(a)(1). In addition to editorial changes, this section now insists that a tap ahead of the main not occur in the same vertical switchboard section. This provision increases the reliability of the tap.
Sec. 695-3(b). For the first time in the NEC, sources that don't originate directly from the utility, i.e. feeders, can supply fire pumps, upon strict conditions.
This is the most critical change. The lack of this type of allowance resulted in the 1996 NEC version of Art. 695, which was "dead on arrival" in thousands of industrial and other campus-style distributions because there simply is no utility source available. A key concept in this subsection involves the distinction between "two or more feeders" (referring to feeders with a common utility source) and "two or more sets of feeders" (each comprised of two or more feeders) originating from separate services. If arranged so a fire at one source won't disrupt the other, then two or more sets of feeders become a legitimate source for a fire pump load.
EC&M alert: If you can't obtain reliable power from the sources in (a), then you need an approved combination of sources in (a), or an approved combination of such sources plus an on-site standby generator, or two or more feeders complying with (2) or (3) (which constitute a partial source), or two or more sets of feeders complying with (2) and (3) (allowable as an entire source). Missing from this list is a standby generator backing up a feeder source. As this is written, the electrical subcommittee of the NFPA 20 (Fire Pump) Committee just endorsed a change in the source document to add this option. Watch for a possible TIA to fix this in the spring.
Sec. 695-4(b). The '99 NEC clarifies the supervision requirements as applying to devices unique to the fire pump loads.
The last sentence of the subsection addressing this point recognizes it is unrealistic to simultaneously monitor all ends of a multiple-ended supply. One end of such supplies could be open and still retain the reliability of supply. Therefore, you must monitor those disconnecting means that could disable a fire pump without causing a general outage that would prompt an immediate response.
Sec. 695-5(c). You must coordinate the transformer size and overcurrent protection, as well as the feeder size and protection so the fire pump will run to failure, without compromising the safety requirements built into other sections of the Code.
Transformers supplying fire pumps generally are reserved for fire pump service exclusively. However, now that the Code recognizes campus distributions, transformers supplying other loads along with the fire pumps need to be covered. Other sections of this article address issues surrounding inadvertent disconnection of the transformer. These transformers are the least likely to be out of service, given the likely perceived criticality of other simultaneously connected loads.
Sec. 695-6(a). The rules for service conductor separation now also apply to fire pump feeder conductors that are part of a qualified source of supply under Sec. 695-3(b)(2). In addition, when routing these conductors through buildings, you can only use Conditions 1 and 2 of Sec. 230-6.
This intentionally excludes Condition 3 of Sec. 230-6, for service conductors in a transformer vault. Although the transformer vault will adequately protect the building from a service conductor fault, a transformer fire within that vault could easily compromise these conductors. The last sentence assures if a campus system involves a radial distribution from one building to the next, then the wiring must comply with service rules in terms of its physical protection and routing outside (or effectively outside) of buildings. This, in turn, reduces the risk that a fire at one building would interrupt protection at another.
Sec. 695-6(a) Ex. In the case of a loop or double-ended system with automatic transfer from one side to the other, the exception waives the service-wiring requirement upstream from that transfer point.
The multiple source of supply assures reliability. The transfer must be automatic for the exception to apply.
Sec. 695-6(b). On the load side of the final disconnecting means with a feeder supply, you must protect the load side conductors from physical or collateral fault damage.
The wording allows you to use enclosed construction with the required rating instead of only permitting electrical circuit protective systems. This avoids the massive problems that developed (and have now been corrected) with similar wording in Sec. 700-9(d). However, you also need to keep these circuits independent of other wiring. This increases reliability by removing the possibility that a fault in an adjacent circuit, such as in a common raceway or cable tray, could take out the fire pump supply. Finally, this section now includes the requirement in NFPA 20 for protection from structural failures, etc.
Sec. 695-6(d). The last sentence essentially introduces the concept of a "service-equivalent tap" (allowing a tap of indefinite length and further reduced size, but physically isolated from the building as per Sec. 230-6) to the Code.
This will allow you much more design flexibility as you look to meeting Code objectives. You want to locate the fire pump disconnecting means remote from other disconnecting means in those cases where it will be fed from feeder circuits, similar to service applications. This makes inadvertent "contemporaneous operation" by the fire service, as covered in Sec. 695-4(b)(2), far less of a possibility.
Background: Here's an example: If you apply conventional tap rules to a 4000A multiple-ended switchboard, even a 10-ft tap would need to be 600 kcmil (at least 400A). Even if you could physically terminate the 600 kcmil conductors in the fire pump disconnect, the 10-ft length limitation would probably leave the fire pump disconnect in the same room. Remember, Sec. 230-6 protects the building from the least protected of all electrical conductors, namely, service conductors. If the tap is run in the same way, the building is equally protected.
Sec. 695-10. This is a new section, requiring listing of fire pump controllers, motors, power transfer switches, foam pump controllers, and limited service controllers.
Sec. 700-6(c). This new rule requires emergency transfer switches to be electrically operated and mechanically held.
The concern is whether a coil failure causes the transfer switch to drop away from the emergency source prematurely.
Sec. 700-9(d)(1). The '99 Code augments the enhanced feeder protection rules. Now you have the following as acceptable protective strategies:
1) Install within fully sprinklered buildings.
The 1996 NEC called for making the feeders run in spaces fully protected by sprinklers; the 1999 NEC asks only that the buildings be fully protected. The result is: It is no longer necessary to sprinkler the feeder itself and its ceiling cavity or chase.
2) Install using a listed electrical circuit protective assembly (same as 1996 NEC).
3) Install using a listed thermal barrier system for electrical system components (the likely successor, over time, to #2).
4) Protect with a 1 hr or better fire-rated assembly (could be multilayer sheetrock, etc.).
5)Embed in 2 inches of concrete.
6) Use a listed circuit-integrity cable.
This is a new type of cable. Although the insulation will degrade on fire exposure, the resulting char still prevents short circuits and ground faults and allows continued functionality for the prescribed time duration.
Art. 710. The '99 NEC draws and quarters this article.
The torso survives as Art. 490 with respect to the medium-voltage equipment requirements; the limbs are distributed to other articles. The EC&M analysis covers them in their new locations.
Sec. 725-24 Ex. 3. A new exception covers "Electronic Power Source Output Conductors." It allows you to protect load-side conductors by line-side overcurrent devices based on the voltage ratio (as if the power supply were just like a simple transformer recognized in Ex. 2).
This is a completely new concept. The electronic power source must be listed.
Sec. 760-2, Fire Alarm Circuit Integrity (CI) Cable. This new cable type ensures continued operation of critical circuits during a specified time under fire conditions.
Although the insulation degrades on fire exposure, the resulting char still prevents short circuits and ground faults and allows continued functionality for the prescribed time.
Sec. 770-6. This section is much more comprehensive than before.
The basic rule is the same: These raceways should be recognized in Chapter 3 and wired accordingly.
However, the exception following (covering listed nonmetallic optical fiber raceway) now specifically refers to one of the types recognized in Sec. 770-51 (that is, in subsections (e), (f), or (g). It calls for the installation to conform to Sec. 331-7 (trimming), 331-8 (joints), 331-9 (making bends), 331-10 (number of bends), 331-11 (supports), 331-12 (fittings and boxes), 331-13 (splices and taps), and 331-14 (bushings). You must terminate unlisted underground or outside plant construction plastic innerduct at the point of entrance. This essentially puts into action the old fine print note on this subject, which is now deleted.
Two more paragraphs follow the exception, covering the allowable raceway fill with optical fiber cables. If there aren't any current-carrying conductors, then you can waive the normal raceway fill restrictions. On the other hand, if nonconductive optical fiber cables share a raceway with electric conductors, the normal fill restrictions do apply.
The '99 NEC also adds a new fine print note, citing the relevant product standard for these raceways (UL 2024).
Sec. 800-48. If you install a raceway wiring method to enclose communications cables and conductors, then it must be a Chapter 3 raceway, and the installation must meet the requirements of Chapter 3. This is a new section structured much like Sec. 770-6. The exception also recognizes a new concept for a "listed nonmetallic communications raceway."
This change has the potential to significantly alter the way we think about the relationship between Chapter 8 and the rest of the Code. Since Chapter 8 stands apart (unless other provisions of the Code are referenced within Chapter 8 (per Sec. 90-3), the Code previously ignored issues such as raceway support and fill. Now, we are seeing a wholesale inclusion of an entire family of Chapter 3 requirements as applicable in a communications environment. Note, however, other Chapter 8 articles don't include this initiative yet.
If you use the nonmetallic product (not a Chapter 3 wiring method) under the exception, you need to comply with selected sections of Art. 331. These include: Sec. 331-7 (trimming), 331-8 (joints), 331-9 (making bends), 331-10 (number of bends), 331-11 (supports), 331-12 (fittings and boxes), 331-13 (splices and taps), and 331-14 (bushings). In plenum cavity ceilings, note this new exception is in direct conflict with Sec. 800-51(j), which only recognizes the optical fiber version (what you'll need to install for now).
Sec. 830-1. This is the beginning of a new article covering network-powered broadband communications systems.
The design and use of these systems provide a combination of voice, audio, video, data, and interactive services. Previously, the NEC did not adequately address powering, grounding, bonding, and electrical protection issues for these new systems in the articles covering communications systems. As explained in the fine print note, the systems typically involve a cable that supplies some power from the network as well as signal to a network interface unit, which converts the broadband signal to their components, such as voice, data, video, etc.
Sec. 830-4 (and table). This sets the allowable power limitations for low and medium power circuits. Both systems share a 100VA maximum power rating, but the medium power source can be up to 150V, as opposed to the 100V limitation on the low power source.
Background: The limitations for this circuit are identical to those for a Class 3 "Not Inherently Limited" circuit, except there isn't any maximum current nameplate rating specified for the power source (due to the potential drop that normally occurs along a service transmission line). To accommodate this variation in potential, the Network Interface Units (NIUs), amplifiers, and other utility equipment operate over a wide range of supply voltages. The supply current to the equipment varies inversely with the voltage.
For example, an NIU connected at a point on the transmission line where the potential is 50V would require twice the current of an NIU connected at a point where the potential is 100V. However, the input volt ampere rating of both would be the same and is not to exceed 100VA. In addition to the 100VA rating, the required 100V overcurrent protection (or equivalent) limits the current to 100V.
Proponents figure the low power source as the likely source for a single-family dwelling, perhaps for an existing CATV subscriber, and the medium power source for similar occupancies with greater functionality, multiple NIUs, or greater distances from the transmission lines. As proposed, there was originally a high power source option with a 150V limit (same as medium power) but a 2250VA power limit. High power cable is a coaxial construction with a grounded shield and 600V insulation on the center conductor, which provide a high level of mechanical protection and electrical isolation of the center conductor. During the comment period, there were serious technical issues raised regarding some of the details. The panel elected to proceed with the new article but only after stripping out the high power provisions.
Sec. 830-5. Both the equipment and cables used on these systems need to be listed for the purpose, although there is the usual cable substitution table (Table 830-58) that allows a better cable to substitute for a lesser one. The first exception, however, grandfathers all CATV system coaxial cables installed per Art. 820 before Jan. 1, 2000 for low power usage.
Although the subsections following essentially cover the usual four-tier hierarchy for this type of cabling (-P, -R, - , -X), there are some interesting gaps. There isn't a BMP cable, for example, so medium-power cabling installed in plenum cavities would default to Sec. 300-22(c) wiring methods. In addition, there isn't a BLR cable, so running low power systems in a riser would require the better grade BMR cable normally identified with medium power applications.
Sec. 830-10(i). The first three paragraphs come directly from Sec. 820-10(f); the fourth paragraph requires protecting network-powered broadband communications cables from damage, to a height of 8 ft from grade. The exception recognizes the use of a listed fault protection device to the circuit provides an acceptable level of protection from electric shock.
With this level of protection on a low power network-powered broadband communications circuit, you can relax the mechanical protection requirements without sacrificing safety.
Sec. 830-11. Due to somewhat greater power levels on these systems, this section includes an additional set of requirements based on the 1996 NEC version (uncorrelated with 1999 changes) of Sec. 300-5 for physical protection of underground power circuits, including a requirement to protect direct-buried cables that make a transition to above grade by using raceway or equal to the point of entrance (or at least to a height of 8 ft).
The section comes with a greatly simplified burial depth table based on Table 300-5, but with many burial depths reduced. There is an exception here, like the one in Sec. 830-10(i)(4), that waives the mechanical protection requirements if there is a fault protection device. The last subsection picks up Sec. 680-10 and its Ex. 2 from the 1996 NEC for underground clearances to swimming pools.
Sec. 830-58(a)(1). These are the rules regarding separation of broadband cables from other wiring.
Low power network-powered broadband communications circuits are essentially Class 3 circuits. Medium power network-powered broadband communications circuits are not Class 3 circuits (similar in some ways but not the same; Class 3 status was denied), but they do have a 600V jacket. With these principles in mind, the separation rules make sense.
First, you can install low and medium power circuits in the same raceway.
Second, with the same circuits, you can install low power circuits in raceways as Class 3 circuits in Sec. 725-54(b)(5), including power-limited fire alarm, CATV, Class 2 and 3, Art. 800 communications, and both conductive and nonconductive optical fiber.
Third, you cannot install medium power circuits in a common raceway or enclosure with any of those same systems, with the only exception being nonconductive optical fiber.
Fourth, the '99 NEC divorces both low power and medium power broadband circuits from nonpower-limited wiring entirely, but with the customary exceptions for barriered separations and for entry into an enclosure housing equipment connected to both systems, with a maintained 1/4-in. air separation.
Chapter 9, Tables. This chapter's title changes from "Tables and Examples" because the '99 NEC relocates all the examples to a new Appendix D.
This clearly locates them as explanatory material, because under NFPA regulations, you cannot place any mandatory material in an appendix. The mandatory material, such as the permission to round off calculations, is now in the regular part of the Code, so nothing is lost. The Code also relocates other examples, such as the ones in Art. 550 and Art. 552, which are now in Appendix D.