Marne and Associates NESC and OSHA Newsletter addresses issues relevant to power and communication utilities.

In This Issue:

• Question 1: Bonding Communication Messengers and Power Neutrals
• Question 2: Joint Use Trenches
• Public Seminar: NESC Rules for Joint Use Construction (2 Day)
• Live Web Seminar: Arc Flash Hazards and Fire Rated Clothing

We have required communication utilties attaching to our poles to bond 8 times per mile. Does the change in Rule 97G in the 2007 NESC require communication messenger to be bonded to the pole ground at every location a pole ground exists?

Yes. If a single grounding conductor (pole ground) is used on the structure, both the neutral and the communication messenger must be bonded to that pole ground. Prior to 2002, the neutral and communication messenger each had to be grounded 4 (or 8) times per mile, but did not need to be bonded together at each structure containing a ground provided other rules for guarding were followed. The 2002 NESC added a new requirement (Rule 97G) using the word "should," and the 2007 edition strengthened the requirement to "shall."

See Fig. 1 for a photo of cable TV and phone messengers bonded to the pole ground. We discuss this and other issues in detail in the NESC Rules for Joint Use Construction 2-day seminar.

Fig. 1 - Messengers Bonded to Pole Ground

What is the clearance required between a communication or power cable in a duct to a gas line?

Joint use trenches as used in a typical subdivision are usually "installed in a duct that is not part of a conduit system" (see NESC Rule 350G). Rule 353A requires a radial separation of at least 12 in between power or communication cables and other underground structures such as gas lines. You should also check with the gas utility involved as they may require greater separations to permit access to and maintenance of the gas facility.

We discuss this and other issues in detail in the NESC Rules for Joint Use Construction 2-day seminar.

NESC Rules for Joint Use Construction
More info.

Coming to Dallas, TX (Sept 16-17); Newark, NJ (Oct 7-8); Atlanta, GA (Nov 12-13); and Missoula, MT (Dec 3-4).

This NESC® seminar is a two-day class focusing on the joint use construction rules in the National Electrical Safety Code® (NESC®). The class will provide an overview of each part of the NESC® that deals with joint use construction (Day 1). Applying the Code to day-to-day work will be stressed by focusing on practical applications and class attendee questions (Day 2). The class includes ample time for questions and attendees are encouraged to share their NESC® applications with the class. The presentation is rich in graphics. More info.

Arc Flash Hazards and Fire Rated Clothing
More info.

Need help meeting the Jan 1, 2009 deadline for the NESC® arc flash rules? Join our 90-minute live web seminar which is offered once a month from August to December. More info.