I received an email from Percy E. Pool, P.E., commenting on my December 2011 column. Percy’s concerns follow.

Don,
   I just got through reading your article “Are You Really Ready for The Triple Play?” in the December 2011 issue of OSP^® magazine.
   I have enjoyed your articles over the years. They have been very useful and have provided a lot of insight about noise and transmission problems in the OSP. However, I think there are several factual errors in your December 2011 article, as shown below.
   Percy E. Pool, P.E.
   Consulting Engineer - Electrical Protection

Percy,
   I have asked an NEC and an NESC guru, Bob Olgeirson, to clarify my statements and misquotes. I sometimes get my NEC and NESC confused.
   Robert Olgeirson is the Manager of Telecom Training & Safety Inc., a non-profit organization providing technical and safety information and training to the employees of 14 telecom companies in and around North Dakota. Bob is a former instructor/adjunct professor of electronics, with 37 years in telecommunications/electronics; 17 of those years training and 20 working and supervising communications maintenance. Percy’s concerns written to me, and Bob’s replies, are below:

PERCY: In the section you describe as “PROBLEM #4: The Network Interface Ground” you make reference to the “2012 NEC”. The latest approved version of the NEC is the 2011 and, as you probably know, the NEC is revised every 3 years so there will never be a “2012 NEC”.

BOB: The column should have read 2012 NESC (and there is a 2012 NESC, revised every 5 years.). NESC Paragraph 99 is entitled “Additional requirements for grounding and bonding of communication apparatus” and states, “Where required to be grounded by other parts of this code, communications apparatus shall be grounded in the following manner.”

“The grounding conductor shall preferably be made of copper (or other material that will not corrode excessively under the prevailing conditions of use) and shall be not less than AWG No. 6 in size.” 2012 NESC Section 9, Paragraph 99 B, Electrode Connection.

(Non-NESC Note: The 2007 and previous versions of the NESC required 14 AWG.)

PERCY: Also, in the same section, you write “The 2012 NEC code states that #10 and #14 ground wire is no longer acceptable”. This is not correct. Article 800.100(A)(3) of the 2011 NEC states “The bonding conductor or grounding electrode conductor shall not be smaller than 14 AWG.”

BOB: Yes, it does. But the 2012 NESC no longer agrees.

PERCY: “It shall have a current-carrying capacity not less than the grounded metallic sheath member(s) and protected conductor(s) of the communications cable. The bonding conductor or grounding electrode conductor shall not be required to exceed 6 AWG.”

BOB: Percy is correct. This statement was added to the NEC in 2011.

PERCY: So, the conductor between the Network Interface Device (NID) and earth ground may be anywhere between 14 AWG and 6 AWG. This article does not say that you can no longer use 10 AWG or 14 AWG.

BOB: The 2012 NESC requires not less than AWG No. 6. The NEC requires not smaller than 14 AWG or larger than 6 AWG.

PERCY: The term NID is used extensively in OSP-related Standards while “Network Interface Ground” is not.

BOB: Our use of the term “Network Interface Ground” (NID) was an attempt at clarity. The term NID is not commonly used in the NEC or in the NESC. The NEC refers to “Primary Protector Grounding”, (“NIU” in Network powered broadband) while the NESC refers to “Communications apparatus”.

PERCY: Further, you write: “The low voltage technician must connect the Network Interface Ground using #6 coated ground wire.” In reality this “ground wire” is “permitted to be insulated, covered or bare” according to Article 800.100(A)(1) of the 2011 NEC.

BOB: Percy is correct. Insulation was required by the 2008 and previous versions of the NEC. The 2011 NEC removed the long-standing insulation requirement, and changed the wording to “insulated, covered or bare”.

PERCY: Lastly, you write “The ground must test from 0 ohms to 25 ohms and no more”. While this requirement may be true in many Telecom Service Providers practices and procedures, the NEC does not support this requirement. Your article has a veiled implication that it does.

BOB: Not so veiled. The NEC (and the NESC) requirement is 25 ohms or less:

The 2011 NEC requires a supplemental electrode -- Unless the resistance is less than 25 ohms. NEC 2011, 250.53 “(2) Supplemental Electrode Required. A single rod, pipe, or plate electrode shall be supplemented by an additional electrode…… “

“Exception: If a single rod, pipe, or plate grounding electrode has a resistance to earth of 25 ohms or less, the supplemental electrode shall not be required.”

Previous NECs also required 25 ohms: “NEC 2008 250.56 Resistance of Rod, Pipe, and Plate Electrodes. A single electrode consisting of a rod, pipe, or plate that does not have a resistance to ground of 25 ohms or less shall be augmented by one additional electrode of any of the types specified by 250.52(A)(4) through (A)(8). Where multiple rod, pipe, or plate electrodes are installed to meet the requirements of this section, they shall not be less than 1.8 m (6 ft.) apart.”

NESC 2012, Section 9, Paragraph 96 C, “Single-grounded systems.

“The ground resistance of individual made electrode used for a single-grounded system should meet the requirements of Rule 96A (minimize hazards) and should not exceed 25 ohms.”

PERCY: I think you owe your faithful readers a revised article with the needed corrections to ensure accuracy. I am surprised you did not validate your information prior to publishing the article. The errors pointed out above could certainly increase the operating costs for Telecom Service Providers unnecessarily. With today’s economy we certainly do not need those additional costs.

DONALD: Percy, I apologize for the confusion with the NEC and the NESC codes, and I thank you, Bob, for clarifying two convoluted codes. I will add additional information and data from Bob Olgeirson in next month’s article so there is no doubt in code requirements by all Telcos. I hope this column provides further insight and clarification for both you and all of my loyal readers.

Signing off
I sincerely appreciate Percy and others taking the time to comment on articles -- whether they are wonderful, not so great, or in between -- and I particularly want to know if I’ve misrepresented anything. Please keep your comments coming -- we all learn together. Contact me at dmccarty@mccartyinc.com.