Original General Order 95

Section V

Detailed Construction Requirements for Supply Lines

(Class H, L and T Circuits)

52.4    Marking

Crossarms Supporting Conductors of More than 750 volts and arms supporting equipment connected to or containing conductors of more than 750 volts shall be marked, by methods described in Rule 52.4-A, as specified in Rules 52.4-B, 52.4-C and 52.4-D with the exceptions specified in Rule 52.4-E

A.    Methods

Crossarms which are required by these rules to marked as high voltage shall be painted a bright yellow color, or in lieu thereof signs showing the words “High Voltage” (or pairs of signs showing the words “High” and “Voltage”) in letters not less than 3 inches in height shall be placed on the face or back in exempted by provisions of the following Rules (52.4-B, C, D, and E).  The letters on such signs shall be white on a green or black background or such signs shall be corrosion-resisting metal with the letters cut out thereform and clearly legible.

B.    Crossarms Supporting Conductors of More than 750Volts and No Conductors of 0-750 Volts.

The Crossarms treated in this Rule 52.4-B may also support certain equipment in addition to conductors of more than 750 volts, and when so utilized the provisions of this Rule 52.4-D will also apply.

(1)    In Urban Districts: All crossarms supporting conductors of more than 750 volts in urban districts shall be marked as high voltage, except as provided in Rule 52.4-B3.

(2)    In Rural Districts: Crossarms Supporting only conductors of more than 750 volts in rural districts shall be marked as high voltage in accordance with the following:

a)    Supporting Conductors of 750-7500 Volts: All crossarms supporting conductors of 750-7500 volts shall be marked as high voltage

b)    Supporting Conductors of Constant Current Circuits of More Than 750 Volts: All crossarms supporting conductors of constant current circuits of more than 750volts shall be marked as high voltage, except as provided in Rule 52.4-B3

c)    Supporting Conductors of 7500-20,000 Volts at certain Locations: At All crossings over public thoroughfares and at locations adjacent to structures such as water tanks, windmills and buildings, adjacent to wells, and at similar locations, crossarms supporting conductors of 7500-20,000 volts shall be marked as high voltage.

d)    Supporting Conductors of More than 750 Volts At or Below the level of Conductors of 7500 Volts or Less: In rural districts, all crossarms supporting conductors of 7500 volts at or below the level of conductors of 7500 volts or less supported on the same structure shall be marked as high voltage.

e)    Supporting Conductors of 7500-20,000 Volts on the Same Structure With Conductors of 750 Volts or Less:  Where, on the same structures in rural districts, crossarms supporting conductors of 7500-20,000 volts are above conductors of 750 volts or less, the crossarm supporting conductors of 7500-20,000 next above the conductors of 750 volts or less shall be marked as high voltage.  All crossarms supporting conductors of 7500-20,000 volts on the same structures shall be marked as high voltage.

(3)    On Guarded Metal Poles: On Latticed metal Poles which are guarded with barriers as required in Rule 51.6-B, the following crossarms shall be marked as high voltage:

Crossarms supporting conductors of 750-7500 volts;

Crossarms supporting conductors of 7500-20,000 volts next above the level of conductors of 7500 volts or less;

Crossarms supporting conductors of 7500-20,000 volts below the level of conductors of 7500 or less;

Crossarms supporting any conductor of more than 7500 volts within 15 feet of walls, fire escapes, exits, windows and similar objects.

Where all conductors on a latticed metal pole which is guarded carry more than 7500 volts and the lowest crossarm supporting them is not required to be marked in accordance with the foregoing provisions of this rule , the entire pole shall be marked as high voltage by means of signs placed on any two opposite sides of the pole at a point above the barrier and below the lowest conductor level.

(4)    On Systems Using Combination Arms: On systems where conductors of 0-750 volts and conductors of 750-7500 volts are usually carried on the same crossarms, any crossarms supporting conductors of 750-7500 volts on both sides of a pole shall be marked as high voltage on both portions to show that the entire crossarm carries high voltage conductors.

C.    Crossarms Supporting Conductors of 750-7500 Volts and Conductors of 750 Volts or Less.  (Combination Arms)

(1)    High Voltage markings: Combination arms shall be marked as high voltage on the portions supporting conductors of 750-7500 volts.  Where paintings is used as the method of marking on such portions of combination arms, the painting shall extend from the ends of the arms to the center line of the pole, or to a position approximately midway between the nearest conductors of different voltage classifications on alley arms or bridge arms.

(2)    Making of Conductors of 750 Volts or Less: On systems where the use of combination arms is so unusual that the requirements of Rule 52.4-B4 are not applied, all combination arms shall be marked as high voltage as specified in Rule 52.4-C1 and in addition thereto a readily legible designation shall be placed on the portions supporting conductors of 750 volts or less.  Such designation shall read “0-750 Volts” or shall indicate the nominal voltage of the circuits of 750 volts or less and shall not read “Low Voltage”

The requirements of this rule do not apply to conductor supporting timbers on transformer structures on systems where no other combination arms are used.

Note-The gradual expansion of the use of combination arms on a system will cause the requirements of Rule 52.4-B4 to become applicable to the entire system.

D.    Crossarms Supporting Miscellaneous Equipment

Included in this group are supporting transformers, cutouts, regulators, oil switches, air switches, capacitors, series controllers, and similar apparatus which are connected to or are a part of the circuit in excess of 750 volts.  These arms shall be marked in accordance with methods specified in Rule 52.4-A

(1)    Hanger Arms, Cutout Arms, Etc: Where yellow paint is used as the method of marking, such arms shall be fully painted except as provided in Rule 52.4-C1.

Where high voltage signs are used as the method of marking, they are required on the face toward the climbing space of hanger arms or of arms supporting cutouts, excepting that signs are not required on any arm supporting cutouts only where such cutout arm is within 30 inches vertically from either a line arm or a hanger arm in which is marked as high voltage.

Where high voltage signs are used as the method of marking, they are not required on the face away from the climbing space of hanger arms supporting cutouts only or of line arms which are not combination arms and which are used as hanger arms, under any of the following conditions:

Where two or more transformers, regulators, or similar pieces of apparatus are supported on the same arm;

Where one or more transformers and one or more oil switches or air switches are supported on the same arm;

Where one or more constant current transformers or regulators and the accompanying series controller are supported on the same arm;

Where one transformer and one or more primary cutouts used in connection therewith are supported on the same arm, providing the conductors leading to theses pieces of apparatus are supported on crossarms immediately adjacent thereto (maximum vertical separation of 30 inches) which are marked as high voltage; or

Where a separate arm used to support cutouts only is within 30 inches vertically from either a line arm or a hanger arm which is marked as high voltage.

(2)    Heel Arms: Heel arms, while treated in these rules as supporting high voltage equipment, are not required to be marked as high voltage.

E.    Exceptions

(1)    Double Arms:  Where high voltage signs are used as the method of marking, they are not required on the inside face of double arms.

(2)    Brackets:  Where extension brackets or clearance brackets are used to extend or supplement crossarms, and support conductors of more than 750 volts, such supplementary supports are not required to be marked as high voltage.