Original Version

Rule 54.4-I

54.4-I.    Under or Through Bridges, Viaducts or Similar Structures

Unprotected supply conductors which pass unattached under bridges, viaducts or other structures shall be maintained at clearances above ground and walkways as specified in Table 1, Cases 1 to 6 incl.; at clearances from walls and underneath parts of such structures as specified in Table 1, Case 7; and at clearances from conductors of other classifications as specified in Table 2, Case 3.

Conductors of 0-22,500 volts, passing under or through bridges, viaducts or similar structures, may be attached thereto in accordance with the provision of Rule 54.4-H2.  Warning signs of a substantial character with letters not less than 3 inches in height reading “High Voltage” for voltages in excess of 750 volts shall be placed conspicuously on each crossarm or structural member supporting the conductors.

In lieu of these requirements for unprotected conductors, supply conductors which cross under bridges, viaducts or other structures shall be enclosed in grounded metal conduit or in other effectively grounded sheath or grounded shield suitably protected from mechanical injury.

Strikeout and Underline Version

Rule 54.4-I

54.4-I.    Under Below, Alongside, or Through, or Immediate Proximity to Bridges, Viaducts or Similar Structures

Unprotected supply conductors which pass unattached under below or in immediate proximity to bridges, viaducts or other similar structures shall be maintained at clearances above ground and walkways as specified in Table 1, Cases 1 to 6 incl. inclusive; at clearances from walls and underneath parts of such structures as specified in Table 1, Case 7; and at clearances from conductors of other classifications as specified in Table 2, Case 3.  The horizontal clearance (Table 1, Case 7) shall be maintained until the vertical clearance (Table 1, Case 6) is attained (see Fig. 54-13).

Conductors of 0-22,500 volts, passing under below or through bridges, viaducts or similar structures, may be attached thereto in accordance with the provision of Rule 54.4-H2.  Warning signs of a substantial character with letters not less than 3 inches in height reading “High Voltage” for voltages in excess of 750 volts shall be placed conspicuously on each crossarm or structural member supporting the conductors.

In lieu of these requirements for unprotected conductors, supply conductors which cross under below bridges, viaducts or other similar structures shall be enclosed in grounded metal conduit or in other effectively grounded sheath or grounded shield suitably protected from mechanical injury.

Final Version

Rule 54.4-I

54.4-I.    Below, Alongside, Through, or Immediate Proximity to Bridges, Viaducts or Similar Structures

Unprotected supply conductors which pass unattached below or in immediate proximity to bridges, viaducts or similar structures shall be maintained at clearances above ground and walkways as specified in Table 1, Cases 1 to 6 inclusive; at clearances from walls and underneath parts of such structures as specified in Table 1, Case 7; and at clearances from conductors of other classifications as specified in Table 2, Case 3.  The horizontal clearance (Table 1, Case 7) shall be maintained until the vertical clearance (Table 1, Case 6) is attained (see Fig. 54-13).

Conductors of 0-22,500 volts, passing below or through bridges, viaducts or similar structures, may be attached thereto in accordance with the provision of Rule 54.4-H2.  Warning signs of a substantial character with letters not less than 3 inches in height reading “High Voltage” for voltages in excess of 750 volts shall be placed conspicuously on each crossarm or structural member supporting the conductors.

In lieu of these requirements for unprotected conductors, supply conductors which cross below bridges, viaducts or similar structures shall be enclosed in grounded metal conduit or in other effectively grounded sheath or grounded shield suitably protected from mechanical injury.