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Line Work — Tree-trimming or brushing
2004 09 01Index:
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| The pages at the
website of the Safety Codes Council state: "Putting the Safety of
Alberta Communities First". Maybe so, but one gains the impression
from visiting their website that what comes before the safety of Alberta
communities is money. The Alberta Electrical and Communication Utility
Code (hereafter called the Code) can be provided by them, apparently only
in hard-copy form, although the latest revised index to the Code is
accessible at the website. But the Code itself cannot be had without
a price.
Consider that it was not all that long ago that such publications were
provided for the asking. That was when Alberta seniors received
grants and subsidies — such as the moneys available under the Winter-Works
Program – and not claw-backs.
Nevertheless, the Code states:
[Note: You must refer to the official version of
the Code to be sure to have the latest information at hand. The
following quote will not necessarily be kept up-to-date as time passes.]
| 3.1.7 |
Tree trimming (1)
Subject to subsection (2), the operator of an electrical utility
system shall ensure that trees near overhead power lines are trimmed
so that the following minimum clearances are maintained at all
times, including the period between tree trims:
- a vertical clearance of 2.0 m plus the minimum distance to
prevent flashover, from the conductors to any portion of a tree
that will support a person; and
- a vertical clearance of 600 mm plus the minimum distance to
prevent flashover, from the conductors to any portion of a tree
that will [not] support a person; and
- a horizontal clearance of 1.0 m plus the minimum distance to
prevent flashover, from the conductors to any portion of a tree
that will support a person; and
- a horizontal clearance of 300 mm plus the minimum distance to
prevent flashover, from the conductors to any portion of a tree
that will not support a person.
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(2) [Subsection (2) was not shown
in the copy of page 49 of the code that I received, although it is
ostensibly a Xerox copy of the latest version of the Code. —WHS] |
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(3) For overhead power or
communication lines with metal sheathed, insulated or polyethylene
covered conductors, operated at voltages below 750 V between
conductors, the minimum clearance between the conductors shall be up
to but not touching. |
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(4) Where trimming is
impracticable, the conductors shall be protected as necessary to
prevent damage and electrical hazards. |
| (3) |
Amend 3.2.3.2. by adding the
following: |
| (3.2.3 |
Protection Against
Climbing – 3.2.3.2 Other Location) |
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(1) Poles or structures of
electrical utility system lines shall not have equipment located on
the pole or structure: |
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- for a minimum distance of 2.5 m above grade level; or
- for a minimum distance of 2.5 m above equipment where
equipment is located on the pole or structure within 2.5 m of
grade level.
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(2) Subsection (1) does not apply
to ground conductors, electrical communication cables, conduits,
riserways, fasteners or gang-operated switch operating handles. |
Let's be realistic, aside from the errors in grammar and
punctuation that I faithfully reproduced in the preceding quote, the
instructions are clear, and their meaning and purpose is unmistakable:
electrical service installations that don't adhere to those requirements
are potential killers of friends and family members. |
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Posted 2004 09 01
Updates:
2005 12 05 (inserted the word "not" in section 3.1.7 §b of the tree-trimming
specifications)
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