Part 1. Electric Supply Stations

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Part 1. Electric Supply Stations
Rules for the Installation and Maintenance of
Electric Supply Stations and Equipment
Jack ChristofersenCeCe Thursday -- July 19, 2001
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Section 10. Purpose and Scope

• The purpose of Part 1 is to provide practical
  safeguarding of persons performing installation,
  operation, or maintenance duties in electric
  supply stations.

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Section 10. Purpose and Scope

• The scope covers the electric supply conductors,
  equipment and structural arrangements in electric
  supply stations, that are accessible only to
  qualified personnel including equipment employed
  primarily for the utilization of electric power
  used by the utility in the exercise of its
  function as a utility.

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Section 11 Protective Arrangements in
Electric Supply Stations
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110. General Requirements

• A1. Types of Enclosures
• Metal fences, when used to enclose
  electric supply stations having
  energized electric conductors or equipment,
  shall have a height not less than 7 ft overall
  and shall be grounded in accordance with
  Section 9.

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110. General Requirements

• A1. Types of Enclosures
• a. Fence Fabric, 7 ft or more in height
• b. A Combination of 6 ft or more or fence
  fabric and utilizing 3 or more strands of
  barbed wire to achieve an overall height of the
  fence of not less than 7ft.

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110. General Requirements

• A2. Safety Clearance Zone
• Fences or walls, when installed as barriers for
  unauthorized personnel, shall be located such
  that exposed live parts are outside the safety
  clearance zone as illustrated in Figure 110-1 and
  shown in Table 110-1.

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110. General Requirements
Live parts must be outside of arc
7ft min.
R
Fence
R
5 ft
Fig 110-1
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110. General Requirements
30

• B. Rooms and Spaces
• All rooms and spaces shall comply with the
  following requirements
• 1. Construction
• They shall be as much as practical
  noncombustible.
• NOTE This Rule is not intended to prevent wood
  poles from being used to support conductors or
  equipment in electric supply stations.

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110. General Requirements
30

• B. Rooms and Spaces
• 2. Use
• They should be as much as practical free from
  combustible materials, dust, and fumes and shall
  not be used for manufacturing or for storage.
• EXCEPTION 1 Equipment or materials essential for
  maintenance of installed equipment may be stored
  if guarded from live parts as required by Rule 124

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110. General Requirements
30

• B. Rooms and Spaces
• EXCEPTION 2 Materials related to station,
  transmission, or distribution construction and
  maintenance work may be stored in the station if
  located in an area separated from the station
  electric supply equipment by a fence meeting the
  requirements of Rule 110A.

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110. General Requirements
30

• B. Rooms and Spaces
• EXCEPTION 3 Stored material related to station,
  transmission, and distribution construction and
  maintenance work in progress may be temporarily
  located in a storage space meeting all of the
  following requirements

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110. General Requirements
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• B. Rooms and Spaces
• (1) Guarded or separated from live parts as
  required by Rule 124
• (2) Station exits continue to meet the
  requirements of Rule 113
• (3) Station working space continues to meet the
  requirements of Rule 125
• (4) Access is limited to qualified personnel
• (5) The storage location and content is such that
  the risk of fire does not unreasonably jeopardize
  station operation.

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Section 12
Installation and Maintenance of Equipment
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120. General Requirements
A. All electric equipment shall be constructed,
installed, and maintained so as to safeguard
personnel as far as practical. B. The Rules of
this Section are applicable to both ac and dc
supply stations.
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124. Guarding Live Parts
Live Part
GUARD ZONE AT RADIUS R, SEE COLUMN 4, TABLE
124-1
VERTICAL CLEARANCE SEE COLULMN 2
TABLE 124-1
HORIZONTAL CLEARANCE SEE COLUMN 3, TABLE 124-1
Fig 124-1
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124. Guarding Live Parts
A. Types of Guards 3. Supplemental Barriers or
Guards Within Electric Supply Stations Railings
are not substitutes for complete guards. If the
vertical distance in Table 124-1 cannot be
obtained, railings or fences may be used.
Railings or fences, if used, shall be not less
than 1.07 m (3.5 ft) high and shall...
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124. Guarding Live Parts
Table 124-1 Part DHigh Voltage Direct Current
(Based on Transient Overvoltage)
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Section 15. Transformers and Regulators
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150. Current-Transformer Secondary Circuits
Protection When Exceeding 600 Volts

• (Old Rule)
• Secondary circuits, when in a primary voltage
  area exceed 600 V should, except for short lead
  lengths at the terminals of the transformer, have
  the secondary wiring adequately protected by
  means of grounded conduit or by a grounded
  metallic covering. Current transformers shall
  have provision for shorting the secondary wiring.

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150. Current-Transformer Secondary Circuits
Protection When Exceeding 600 Volts

• (New Rule)
• Secondary circuits, when in the vicinity of
  primary circuits exceeding 600 V should, except
  for short lead lengths at the terminals of the
  transformer, have the secondary wiring adequately
  protected by means of conduit covering or some
  other protection. Any metallic covering used
  shall be effectively grounded, giving appropriate
  consideration to circulating currents. Current
  transformers shall have provision for shorting
  the secondary winding.

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Section 17. Circuit Breakers, Reclosers,
Switches, and Fuses
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170. Arrangement
Circuit breakers, reclosers, switches, and fuses
shall be so installed as to be accessible only to
persons qualified for operation and
maintenance... Conspicuous markings (such as
numbers/ letters/ symbols) shall be provided on
each device and at any remote operating points so
as to facilitate identification by employees
authorized to operate the device. No device
identification shall be duplicated within the
same supply station.