Question 1. I seem to be frequently involved in discussions over the use of cable ties as a supporting means for metal-clad cable. Section 330.30 doesn’t clearly state that cable ties can be used as a support method. I am aware that cable ties are clearly defined as an approved method in the following Code locations: 320.30, 334.30, 338.10(B)(b), and 340.10(4). Could you give us your take on this subject? — G.C.

Answer 1.  Article 330.30 of NEC 2002 requires Type MC cable to be supported and secured at intervals not exceeding 1.8 m (6 ft). Article 300.11 also applies and requires cable assemblies to be securely fastened in place. Article 320.30 allows cable ties to be used to secure type AC cable and does not allow cable ties to be used to support type AC cable. Articles 334.30, 338.10(B)(4)(b), and 340.10(4) also reference cable ties for securing but not for supporting cables. Cable ties are specifically mentioned in 2002 Code articles for securing cable type wiring methods but not as the supporting means. — Gaylen Rogers, CMP-17

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Question 2. I was under the impression that the number 8 bond wire did not have to go to the electrical panel, but only from the tub motor to the piping systems and any associated electrical equipment. — W. H.

Answer 2. Hydromassage tub installations are covered by Section 680.70 in NEC 2002. Since there appears to be confusion about the difference between grounding and bonding, let’s go back to the basics. The requirements for the bonding of a hydromassage tub are found in Section 680.74, Bonding. In order to answer this question let’s review the following sections that apply to this type of installation:

"680.74 Bonding. All metal piping systems, metal parts of electrical equipment, and pump motors associated with the hydromassage tub shall be bonded together using a copper bonding jumper, insulated, covered, or bare, not smaller than 8 AWG solid. Metal parts of listed equipment incorporating an approved system of double insulation and providing a means for grounding internal nonaccessible, non-current-carrying metal parts shall not be bonded."

Let’s examine what bonding really is. Since there is not a definition of bonding that is specific to Article 680, we must refer to the definition of bonding found in Article 100.

"Bonding (Bonded): The permanent joining of metallic parts to form an electrically conductive path that ensures electrical continuity and capacity to conduct safely any current likely to be imposed."

In this case we are discussing bonding as it pertains to "the permanent joining of the metallic parts" of a hydromassage tub as required by Section 680.74. This requirement is to tie all metal parts together to insure that they are at the same potential. This requirement for bonding just requires you to bond the metal parts together, even though in reality, in most instances it will be tied back to the grounding electrode system through the equipment grounding conductor that is run to the pool equipment with the branch -circuit wiring. This requirement for bonding should not be confused with the requirement for grounding as provided to the pump motor by the equipment grounding conductor which is usually required to be a 12 AWG wire for a 20-amp circuit. The bonding requirement of Section 680.74 does not require you to run the required 8 AWG conductor back to the panelboard feeding the circuit that runs to the pump motor. There was a new fine print note added to Section 680.26(A) in the 2002 NEC that clarifies the intent of this requirement and should probably be added to Section 680.74 also.

"680.26(A), Performance. The bonding required by this section shall be installed to eliminate voltage gradients in the pool area as prescribed.

"FPN: This section does not require that the 8 AWG or larger solid copper bonding conductor be extended or attached to any remote panelboard, service equipment, or any electrode." — Jim Maldonado, CMP-17

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Question 3.An outdoor spa has an approved cover. The cover has a metal railing that is mounted to the spa at the bottom rear and extends up and around the cover top when the cover is closed. Does this metal railing have to be bonded? The cover may be removed while this metal railing remains attached to the spa. Also the spa has a metal railing for entering the spa. This metal railing rotates up and over the water in the spa (about 1-1/2') and then rotates in the opposite direction away from the spa. The railing is mounted to the spa wall with nonmetallic brackets. The railing is approximately four feet long. Does this have to be bonded? — R. H.

Answer 3. An outdoor spa is covered in the 2002 NEC under Section 680.40. From the description given, let’s assume that there are metallic pipe railings attached to the spa structure that will remain in place while the spa is in use. Let’s also assume that these rails are attached to the pool structure without a direct metal- to-metal connection to the metal frame of the spa assembly and that the length of these rails exceed 100 mm (4 in.) in any dimension.

In order to answer this question let’s review the following sections that apply to this installation:

680.42 Outdoor Installations. "A spa or hot tub installed outdoors shall comply with the provisions of Parts I and II of this article, except as permitted in 680.42(A) and (B), that would otherwise apply to pools installed outdoors."

680.42(B) Bonding. "Bonding by metal-to-metal mounting on a common frame or base shall be permitted. The metal bands or hoops used to secure wooden staves shall not be required to be bonded as required in 680.26."

680.26(B)(3) Metal Fittings. "All metal fittings within or attached to the pool structure shall be bonded. Isolated parts that are over 100 mm (4 in.) in any dimension and do not penetrate into the pool structure more than 25 mm (1 in.) shall not require bonding."

The installation as described, would require that these railings be bonded, as required in Section 680.42, since the metallic parts exceed 4" in any dimension, there is no metal-to-metal mounting, and they will be within 1.5 m (5 ft) of the spa. — Jim Maldonado, CMP-17

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Question 4. As a new electrical inspector I have been asked to show where in the Code it is required to have a disconnect (not cord-and-plug) for a water heater. The cord–and-plug is the issue. It has been a practice in the past to use dryer receptacles and cords for the disconnecting means. The previous inspector changed this to using an a/c disconnect as being acceptable. The Code sections I have used to prove this are 422.16, 400.7, 422.13, 422.30 and 427.55(B). Are there better references to use and where can I find listed appliances?  —T

Answer 4. You are correct that water heaters are defined as an appliance, by the definition of appliance in Article 100. The article that covers appliances in the 2002 NEC is 422. Water heaters are specifically mentioned in 422.13. Section 422.30 requires a disconnecting means for appliances in accordance with Part III of Article 422. According to 422.31(B) "the branch-circuit switch or circuit breaker shall be permitted to serve as the disconnecting means where the switch or circuit breaker is within sight from the appliance or is capable of being locked in the open position." The past practice of using cords and plugs is covered in 422.16(A), which limits the use of flexible cords to connect appliances to those applications that meet certain conditions. Condition (1) is "to facilitate their frequent interchange or to prevent the transmission of noise or vibration." Water heaters do not require frequent interchange nor do they usually transmit vibration or noise through the wiring methods. Condition (2) is where "the appliance is intended or identified for flexible cord connection." Usually in order for the AHJ to determine if an appliance is intended to be cord-and-plug connected, the appliance would come with the cord attached from the factory, or "identified for flexible cord connection" it would be listed and labeled for cord-and-plug connection. See the definition of identified in Article 100 and the fine print note (FPN). In most water heater installations a disconnect switch is located adjacent to the water heater to meet the disconnect requirements of 422.30. You also quoted 427.55(B) as an applicable code requirement. This section covers "fixed electrical pipeline or vessel heating equipment" and does not cover water heaters; therefore, this section would not be applicable to this installation. —Jim Maldonado, CMP-17, alternate

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Question 5. I have inspected an installation of a heated floor in a bathroom at a home where the installer had roughed in a low-voltage (35-volt AC) floor tile heater mat. I asked about the compliance with NEC 424.44(G) and the answer that I received from a NRTL was that GFCI protection was not required because the low voltage was equal to GFCI protection. The primary of the transformer is 240V / 30A, with non GFCI protection. Please give me your comments. Thank you in advance. — G.L.

Answer 5. In reviewing the NEC-2005, Section 424.44(G), I cannot find an exception for a low-voltage system that would allow for low-voltage systems to not be protected with GFCI protection. During the NEC-2005 ROP process, there were code change submittals to this section. Under proposal 17-34, it was proposed to change the requirement for GFCI protection to GFP protection, this proposal was rejected since the intent of the section is for personnel protection, not for equipment protection. Under proposal 17-37, it was proposed that “Listed Equipment provided with an isolation transformer including a grounded shield between primary and secondary windings does not need to be additionally protected by Ground-fault Circuit interrupter protection.” This proposal was rejected in the ROP stage. Under the NEC-2005, I do not see where being a low-voltage system equals GFCI protection as required by 424.44(G).
— Jim Maldonado, CMP-17
(January/February 2007)

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