Investigate.Laws
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- Location
- Meridian, Idaho, USA
We have an AV equipment rack manufactured by Chief Manufacturing. It's a wall-mounted rack model (SWR-24-17). Inside, we keep AV equipment mounted to the rack rails. Power for the AV equipment is being supplied by two, rack-mounted power strips manufactured by Furman. The power strips are model M-8x2. These power strips are plugged into wall outlets below the wall-mounted AV equipment rack. This rack is used in a classroom with the usual students, faculty, and staff coming into contact with it.
Chief supplies two green bonding jumper cables. One of the green bonding jumper cables connects the front door of the rack to one of the rack's interior bonding studs. A second green bonding jumper cable connects another bonding stud within the rack to one of the rack rails.
The Furman power strips do not have bonding studs.
However, I'm reading a document produced by rack manufacturer "Great Atlantic" that suggests power supplies within a rack have metal chassis that should be connected to one of the bonding studs within the rack with a similar green bonding jumper cable.
In addition, InfoComm International, the professional association representing the commercial audiovisual industry, has just published a new textbook for AV installers who seek to become certified by InfoComm International (CTS-I). This is an ANSI-accredited certification.
That textbook strongly suggests likewise: Power strips within an audiovisual equipment rack have metal chassis that should be bonded to the rack's bonding stud using the green bonding jumper cable.
I've asked the authority having jurisdiction, a State of Idaho Division of Building Safety, if the green jumper cable is required for power supplies within the rack to be connected to the rack's bonding stud.
Idaho's current "interpretation" of NEC code is, apparently, that such a bonding jumper cable is *not* required as long as the power strip "is properly grounded." I assume they are talking about the standard three-prong power plug that the power strips use to plug into the wall outlet.
I'm confused. On the one hand, InfoComm and a major rack manufacturer strongly advise the bonding jumper to connect the power strip chassis to the rack stud for safety reasons. On the other hand, the local authority having jurisdiction says it's not required. As you may already surmise, when something like this is not required, it won't get done.
What does the NEC code really require, in this circumstance?
I wish to point out that InfoComm International makes the point that the rack ears of an audiovisual rack-mounted power supply should not be expected to bond, necessarily, due to paint on the rack rails. That's why the bonding jumper solution is recommended, apparently. The author, Dr. Shonan Noronha, Ed.D., writes: "Racks cannot be effectively bonded through PDU (power distribution unit) rack ears or through power strip mounting clips. Rack power should be bonded to the grounding stud on the rack."
I've found a U.S. Department of Energy document that also seems to support this type of bonding.
Are the Idaho folks mistaken?
P.S. Every time I touch this rack, I get the familiar static electricity "pop."
Chief supplies two green bonding jumper cables. One of the green bonding jumper cables connects the front door of the rack to one of the rack's interior bonding studs. A second green bonding jumper cable connects another bonding stud within the rack to one of the rack rails.
The Furman power strips do not have bonding studs.
However, I'm reading a document produced by rack manufacturer "Great Atlantic" that suggests power supplies within a rack have metal chassis that should be connected to one of the bonding studs within the rack with a similar green bonding jumper cable.
In addition, InfoComm International, the professional association representing the commercial audiovisual industry, has just published a new textbook for AV installers who seek to become certified by InfoComm International (CTS-I). This is an ANSI-accredited certification.
That textbook strongly suggests likewise: Power strips within an audiovisual equipment rack have metal chassis that should be bonded to the rack's bonding stud using the green bonding jumper cable.
I've asked the authority having jurisdiction, a State of Idaho Division of Building Safety, if the green jumper cable is required for power supplies within the rack to be connected to the rack's bonding stud.
Idaho's current "interpretation" of NEC code is, apparently, that such a bonding jumper cable is *not* required as long as the power strip "is properly grounded." I assume they are talking about the standard three-prong power plug that the power strips use to plug into the wall outlet.
I'm confused. On the one hand, InfoComm and a major rack manufacturer strongly advise the bonding jumper to connect the power strip chassis to the rack stud for safety reasons. On the other hand, the local authority having jurisdiction says it's not required. As you may already surmise, when something like this is not required, it won't get done.
What does the NEC code really require, in this circumstance?
I wish to point out that InfoComm International makes the point that the rack ears of an audiovisual rack-mounted power supply should not be expected to bond, necessarily, due to paint on the rack rails. That's why the bonding jumper solution is recommended, apparently. The author, Dr. Shonan Noronha, Ed.D., writes: "Racks cannot be effectively bonded through PDU (power distribution unit) rack ears or through power strip mounting clips. Rack power should be bonded to the grounding stud on the rack."
I've found a U.S. Department of Energy document that also seems to support this type of bonding.
Are the Idaho folks mistaken?
P.S. Every time I touch this rack, I get the familiar static electricity "pop."