Original Rule
Rule 58.3-C3
58.3-C3) Transformer Case Grounding or Bonding: Cases
of transformers and metal parts in contact therewith shall not be grounded
where supported on wood poles or wood structures.
The hanging or placing of transformers on metal poles or structures
is not recommended, particularly with respect to transformers connected to
circuits of less than 14,000 volts. Transformers shall not be supported
on metal poles or metal supports in contact with the ground unless the cases
are securely bonded to the metal poles or parts of structures in contact
with the ground and such poles or structures are effectively grounded.
No transformer case shall be in contact with a metal crossarm or a metal
beam attached to a wood pole or a wood structure, excepting a metal heel
arm or rest which does not extend beyond the sides of any transformer case.
The bonding of cases of transformers whose high voltage windings are connected
to circuits of less than 20,000 volts is not recommended but where such cases
are bonded the case bonding system shall not be electrically connected to
any unassociated hardware or to other bonds.
Except from the provisions of this Rule 58.3-C3 applying to the grounding
of transformer cases supported on wood poles or structures are the following:
Any transformer whose high-voltage winding is connected
to a circuit of more than 14,000 volts, which may have its case grounded
provided all such transformer installations on the system are so grounded,
warning signs calling attention to the case grounding condition are posted
on the structure so as to be readily legible from the climbing space or spaces,
and no such grounded transformer case is less than 8 feet vertically or 4
feet horizontally from the unprotected conductors of any other supply-line
circuit than those to which the transformer windings are connected;
Any transformer whose high-voltage is connected to a circuit of 750-14,000
volts, which may have its case grounded provided no unprotected conductors
(including lead wires) of 750-14,000 volts shall be less than 8 feet vertically
or 4 feet horizontally from the nearest part of such grounded case; and
Any transformer the case of which is less than 8 feet above the ground.
Transformer cases which are grounded in accordance with any provision of
this rule shall be effectively grounded (see Rule 33.3).
Strikeout and Underline Version
Rule 58.3-C3
58.3-C3) Transformer Case Grounding or Bonding:
Cases of transformers and metal parts in contact therewith shall not be grounded
where supported on wood poles or wood structures.
T Except in the case of partial underground
distribution systems (see Rule 21.10), the hanging or placing of transformers
on metal poles or structures is not recommended, particularly with respect
to transformers connected to circuits of less than 14,000 volts. Transformers
shall not be supported on metal poles or metal supports in contact with the
ground unless the cases are securely bonded to the metal poles or parts of
structures in contact with the ground and such poles or structures are effectively
grounded. No transformer case shall be in contact with a metal crossarm
or a metal beam attached to a wood pole or a wood structure, excepting a
metal heel arm or rest which does not extend beyond the sides of any transformer
case.
The bonding of cases of transformers whose high voltage windings are connected
to circuits of less than 20,000 volts is not recommended but where such cases
are bonded the case bonding system shall not be electrically connected to
any unassociated hardware or to other bonds.
Except from the provisions of this Rule 58.3-C3 applying to the grounding
of transformer cases supported on wood poles or structures are the following:
Any transformer whose high-voltage winding is connected
to a circuit of more than 14,000 volts, which may have its case grounded
provided all such transformer installations on the system are so grounded,
warning signs calling attention to the case grounding condition are posted
on the structure so as to be readily legible from the climbing space or spaces,
and no such grounded transformer case is less than 8 feet vertically or 4
feet horizontally from the unprotected conductors of any other supply-line
circuit than those to which the transformer windings are connected;
Any transformer whose high-voltage is connected to a circuit of 750-14,000
volts, which may have its case grounded provided no unprotected conductors
(including lead wires) of 750-14,000 volts shall be less than 8 feet vertically
or 4 feet horizontally from the nearest part of such grounded case; and
Any transformer the case of which is less than 8 feet above the ground.
Transformer cases which are grounded in accordance with any provision of
this rule shall be effectively grounded (see Rule 33.3).
Final Version
Rule 58.3-C3
58.3-C3) Transformer Case Grounding or
Bonding: Cases of transformers and metal parts in contact therewith shall
not be grounded where supported on wood poles or wood structures.
Except in the case of partial underground distribution systems (see Rule
21.10),the hanging or placing of transformers on metal poles or structures
is not recommended, particularly with respect to transformers connected to
circuits of less than 14,000 volts. Transformers shall not be supported
on metal poles or metal supports in contact with the ground unless the cases
are securely bonded to the metal poles or parts of structures in contact
with the ground and such poles or structures are effectively grounded.
No transformer case shall be in contact with a metal crossarm or a metal
beam attached to a wood pole or a wood structure, excepting a metal heel
arm or rest which does not extend beyond the sides of any transformer case.
The bonding of cases of transformers whose high voltage windings are connected
to circuits of less than 20,000 volts is not recommended but where such cases
are bonded the case bonding system shall not be electrically connected to
any unassociated hardware or to other bonds.
Except from the provisions of this Rule 58.3-C3 applying to the grounding
of transformer cases supported on wood poles or structures are the following:
Any transformer whose high-voltage winding is connected
to a circuit of more than 14,000 volts, which may have its case grounded
provided all such transformer installations on the system are so grounded,
warning signs calling attention to the case grounding condition are posted
on the structure so as to be readily legible from the climbing space or spaces,
and no such grounded transformer case is less than 8 feet vertically or 4
feet horizontally from the unprotected conductors of any other supply-line
circuit than those to which the transformer windings are connected;
Any transformer whose high-voltage is connected
to a circuit of 750-14,000 volts, which may have its case grounded provided
no unprotected conductors (including lead wires) of 750-14,000 volts shall
be less than 8 feet vertically or 4 feet horizontally from the nearest part
of such grounded case; and
Any transformer the case of which is less than 8 feet above the ground.
Transformer cases which are grounded in accordance with any provision of this rule shall be effectively grounded (see Rule 33.3).