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Bonding Copper Piping for a Hydromassage Tub

Posted By Keith Lofland, Thursday, March 01, 2012
Updated: Monday, February 04, 2013

Question

A minimum 8 AWG copper bonding conductor is utilized to bond the hot and cold copper water piping rising from the ground to serve a hydromassage bathtub along with other metal components installed under the hydromassage bathtub. Why does the Code require installers to run a bonding conductor to the location of a double insulated circulating pump motor when this bond wire is not required to be connected to anything?

Answer

All metal piping associated with a hydromassage bathtub and all grounded metal parts in contact with the circulating water is required be bonded together using an 8 AWG solid copper bonding jumper. This bonding jumper is required to be connected to the terminal on the hydromassage bathtub circulating pump motor. Furthermore, this bonding jumper should not be connected to a double insulated circulating pump motor (680.74). A change was implemented in the 2011 NEC at 680.74 to require an 8 AWG or larger solid copper bonding jumper long enough to terminate on a replacement non-double insulated pump motor. This bonding jumper is to terminate to the equipment grounding conductor of the branch circuit of the motor when a double insulated circulating pump motor is used. This added language here at 680.74 is similar to the wording found at 680.26(B)(6)(a) for a double insulated circulating pump motor and possible replacement at a permanently installed swimming pool. This bonding jumper for a double insulated circulating pump motor is required to be in place in the event that the double insulated motor is replaced at a future date with a non-double insulated motor, which would require the bonding jumper for bonding to associated metal components. Inspectors and installers alike will have to decide what to do with the other end of this 8 AWG or larger solid copper bonding jumper if a double insulated circulating pump motor is employed and no metal piping and no grounded metal parts are present.

— Keith Lofland, IAEI Director of Education

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Tags:  Focus on the Code  March-April 2012 

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Connecting IT Equipment

Posted By Keith Lofland, Thursday, March 01, 2012
Updated: Monday, February 04, 2013

Question

Can information technology equipment be cord-and-plug connected if the cord is either hard usage type or portable power cable type? Is such IT equipment required to be marked as being suitable for cord-and-plug connection before such connection be utilized? Is there a maximum length for power-supply cords used to connect IT equipment as well as for cables that interconnect separate IT equipment? JP

Answer

First, we must assume that the information technology equipment in question does qualify as IT equipment by meeting all of the six conditions listed at 645.4. If the IT equipment in question does not meet all of the special conditions of 645.4, then this equipment would be subject to the provisions of Chapters 1 through 4 of theNEC.
 
Figure 1. Typical IT equipment, cord-and-plug connected under a raised floor.

Section 645.5(B)(2) covers the type of cords that are permitted for IT equipment and the terms "hard usage” and "portable power cable” are not used in this section. This subsection does require IT power cords to be listed and of a type permitted for use on listed information technology equipment. Section 645.5(B)(2) also permits power cords constructed of listed flexible cord and listed attachment plugs and cord connectors of a type permitted for information technology equipment. Section 645.4(3) requires all information technology equipment to be listed and the determination of whether the IT equipment can be cord-and plug-connected is better suited for the product standards and the product certifications rather than theNEC. From the UL White Book Category "NWGQ” the following is stated, "When listed equipment intended for use with a detachable power-supply cord is not provided with such a cord, a cord suitable for connection of the equipment to the branch circuit should be separately provided.” The length of the power-supply cord for IT equipment is limited to 4.5 m (15 ft) by Section 645.5(B)(1). Interconnecting cables are not limited to 4.5 m (15 ft) like the power-supply cables as noted at 645.5(C). Interconnecting cables are required to be listed but the length of the interconnecting cable is not restricted by theNEC.

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Tags:  Focus on the Code  March-April 2012 

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