General Order 64-A
Section IV
Strength Requirements For All Classes Of Lines
49.3 Pins and Conductor Fastenings
A. Material
(1) Pins: Insulator pins shall be of galvanized steel, galvanized iron or other corrosion-resisting metal or of locust or other suitable wood.
(2) Fastenings: Conductor fastenings shall be of galvanized steel, galvanized iron or other corrosion-resisting metal.
B. Size
(1) Wood Pins: The minimum diameter of the shank shall not be less than 1 ¼ inches.
(2) Metal Pins: The minimum diameter of the shank shall not be less than ½ inches.
(3) Tie Wires: The minimum size of tie wire for a particular gauge of line conductor is given in the following table:
Table 6 |
||
| Line material |
Conductor gauge |
Tie wire gauge |
| Copper (A.W.G.) |
6 and smaller |
Size of line conductor |
| 4 |
6 |
|
| 2 and 0 |
4 |
|
| 00 and larger |
2 |
|
| Iron and Steel B.W.G |
9 and smaller |
Size of line conductor |
| 8 |
Not smaller than 9 |
|
| 4 and 6 |
8 |
|
C.
Strength
Insulator pins shall be able to
withstand the loads to which they may be subjected with safety factors at least
equal to those of Rules 44, Table 4.
(1) Tensions: For conductor tensions up to 2000 pounds per conductor which are supported on pins and insulators, double pins and insulators with tie wires, or equivalent fastenings, will be considered as meeting the strength requirements of Rule 47.4 and 47.5.
(2) Longitudinal Stresses:
a) Pins and Conductor Fastenings: Where longitudinal stresses are normally
balanced, pins and conductor fastenings, other than tie wires, shall have
sufficient strength to withstand as a minimum a stress of 700 pounds.
A standard 1 ½ by 9 inch locust
pin provides strength up to 1000 pounds tension in the conductor, with the
conductor 3 ½ inches above the cross arm.
b) Tie Wires: Tie wires and fastenings shall have no sharp
edges at points of contact with conductors, and shall be applied in such manner
as not to damage the conductor.
Tie wires shall be installed in
such a manner that they will securely hold the line conductor to its supporting
insulators. This will permit without
slipping of conductor an unbalanced pull equal to the following percentage of
the allowable tension of the conductor, to a maximum of 500 pounds:
|
Supply line tie wires |
40% |
Communication line tie wires |
15% |
D. Replacements (see Rule 44.2)