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Marne and
Associates NESC and OSHA Newsletter addresses
issues relevant to power and communication
utilities.
In This Issue:
2012 NESC
Proposed Change:
Low Voltage Arc Flash
Table
The change proposals for
the 2012 NESC have been published to gather
industry comments. Comments are due by May 1,
2010.
Change proposal CP3042
deals with arc flash assessments to determine
the arc rating of clothing worn by power lineman
and others in the utility industry. The 2007
Edition of the NESC contained new tables for
selecting arc rated clothing. The new 2007
tables did not address low voltage systems. A
new table has been proposed for voltages below
1000V for use in the 2012 NESC. Industry comment
is needed to review this new table. To get your
voice heard, the first step is to purchase the
Preprint Proposals for the 2012 Edition of the
NESC (unfortunately this document is not
available for free). The second step is to
follow the electronic revision process to submit
your comments to the code committees.
To order a copy of the
Preprint Proposals for the 2012 Edition of the
NESC click
here.
2012 NESC
Proposed Change:
Guy insulator
placement
The change proposals for
the 2012 NESC have been published to gather
industry comments. Comments are due by May 1,
2010.
Change proposal CP3480
deals with guy insulator placement. The NESC
rules permit grounding or insulating guy wires.
If guy wires are insulated there are
requirements for the location of the guy
insulator. Confusion exists as to the exact
placement of the guy insulator.
This confusion exists by
those using the Code and by those writing the
Code as evidenced by excerpts from
Interpretations Request IR551 (excerpts shown
below):
Request for
Interpretation:
This Rule [NESC Rule
215C5b] states: "Insulators shall be so placed
that, in case any guy or span-wire contacts, or
is contacted by, an energized conductor or part,
the voltage will not be transferred to other
facilities on the
sturucture(s)."
a) Does this Rule
require insulation between distribution primary
voltage conductors and secondary voltage supply
conductors?
b) Does this Rule require
insulation between distribution primary voltage
conductors and the system neutral supply
conductor?
c) Does this Rule
require insulation between the distribution
system neutral supply conductor and
communication conductors?
Interpretation:
"We regret that the NESC
Interpretations Subcommittee cannot achieve
consensus on this Interpretation Request and
that, therefore, an interpretation cannot be
rendered."
This Interpretation
Request prompted the Code Committee to revise
the guy insulator rule in the 2012 NESC. The
change proposal for this rule is attempting to
clarify the guy insulator location wording.
Industry comment is needed to review the
proposed changes to this rule. To get your voice
heard, the first step is to purchase the
Preprint Proposals for the 2012 Edition of the
NESC (unfortunately this document is not
available for free). The second step is to
follow the electronic revision process to submit
your comments to the code committees.
To order a copy of the
Preprint Proposals for the 2012 Edition of the
NESC® click
here.
Reminder: Marne and
Associates NESC Live Web Seminar Series Begins
Again in January 2010.
Marne and Associates new
cycle of NESC live web seminars begins again in
January 2010.
This is a great low
cost, no travel, and easy way to get NESC
training for your engineering or operations
personnel. More
Info.
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