Original Version

Rule 84.4-F

84.4-F.    Under Or Through Bridges, Viaducts or Similar Structures

Open wire communication conductors which cross under or through bridges, viaducts, or similar structures shall be maintained at clearances above ground and walkways a two specified in Table 1, Cases 1 to 6; at a radial clearance from unprotected conductors of other classifications not less than as specified in Table 2, Case 3; at clearance from walls and the underside of such structures as specified in Table 1, Case 7 except where it is not practicable to obtain the 3-foot clearance therein specified this clearances may be reduced to not less than 6 inches where the voltage does not exceed 160 volts; or where supported on the walls or underside of such structures, at clearances as specified in Table 1, Case 9 with supports at least every 50 feet.

In lieu of the above requirements, conductors which cross under or through bridges, viaducts, or similar structure shall be enclosed in metal sheaths, run in metal conduits ill or be placed in ring construction on a messenger.

Strikeout and Underline Version

Rule 84.4-F

84.4-F.    Under Or Below, Alongside, Through or In Immediate Proximity to Bridges, Viaducts or Similar Structures

Open wire communication conductors which cross under or below through or in immediate proximity to bridges, viaducts, or similar structures shall be maintained at clearances above ground and walkways a two specified in Table 1, Cases 1 to 6; at a radial clearance from unprotected conductors of other classifications not less than as specified in Table 2, Case 3; at clearance from walls and the underside of such structures as specified in Table 1, Case 7.  The horizontal clearance (Table 1, Case 7) shall be maintained until the vertical clearance (Table 1, Case 6) is attained (see Fig. 84-4). except wWhere it is not practicable to obtain the 3-foot clearance, therein specified this clearances may be reduced to not less than 6 inches where the voltage does not exceed 160 volts; or where supported on the walls or underside of such structures , at clearances as specified in Table 1, Case 9 with supports at least every 50 feet.

In lieu of the above requirements, conductors which cross under below or through bridges, viaducts, or similar structure shall be enclosed in metal sheaths, run in metal conduits ill or be placed in ring construction on a messenger.

Final Version

Rule 84.4-F

84.4-F.    Below, Alongside, Through or In Immediate Proximity to Bridges, Viaducts or Similar Structures

Open wire communication conductors which cross below through or in immediate proximity to bridges, viaducts, or similar structures shall be maintained at clearances above ground and walkways a two specified in Table 1, Cases 1 to 6; at a radial clearance from unprotected conductors of other classifications not less than as specified in Table 2, Case 3; at clearance from walls and the underside of such structures as specified in Table 1, Case 7.  The horizontal clearance (Table 1, Case 7) shall be maintained until the vertical clearance (Table 1, Case 6) is attained (see Fig. 84-4). Where it is not practicable to obtain the 3-foot clearance, this clearances may be reduced to not less than 6 inches where the voltage does not exceed 160 volts; or where supported on the walls or underside of such structures at clearances as specified in Table 1, Case 9 with supports at least every 50 feet.

In lieu of the above requirements, conductors which cross below or through bridges, viaducts, or similar structure shall be enclosed in metal sheaths, run in metal conduits ill or be placed in ring construction on a messenger.