Milliken E177

Contents

• Overview
  • General data
• Lines
• Tower forms
  • Single circuit
  • Double circuit
  • Four circuit
• Earthing arms
  • Examples
• Tower details
• See also

Overview

E177 is a 33 kV distribution tower type, used on contract SWE SL2 and apparently (not verified) also SWE SL3. E177 is notable for including quad-circuit towers: these have four crossarms in long–short pairs. The upper two crossarms carried the double-circuit line from Nursling to Salisbury while the lower two crossarms carried the double-circuit line from Nursling to Winchester. The quad-circuit line split out into separate double-circuit lines on a junction tower in Romsey. Today, the quad-circuit towers carry only two circuits instead of four. (The quad-circuit types are described as “four circuit” and use a designation prefix of “F”.)

General data

Lines

• An originally four-circuit line from Nursling to Romsey, dividing at Romsey into two double-circuit lines:
  • Romsey to Salisbury (mostly demolished)
  • Romsey to Winchester
• Bridgwater to Williton (single circuit)

Romsey–Salisbury/Winchester is the only line confirmed to be part of SWE SL2.

Tower forms

The D3, S3, S10 and F3 towers are narrow base (with no bend line), and the S10 and D10 angle towers are of the suspension type. The only known D10 towers—those visible on Google Street View—are all in straight line positions and appear to have been chosen for supporting long spans; there are also S10 towers used in straight line positions.

The following diagrams are shown to scale at 12 pixels per metre.

Single circuit

Double circuit

Four circuit

The outline and dimensions for the (undesignated) F3 tower are given in [Marshall]. Google Street View was used to correct the diagram.

The F72 diagram is taken from the orientation and line diagram (XM911-78A) for the junction tower where the quad-circuit line from Nursling divided at Romsey into conventional double-circuit lines to Salisbury and Winchester. This junction tower uses the F72 E20 body with the outer-angle, square-ended F72 crossarms on both sides. Very little of the tower is depicted, so the inner-angle crossarms and the body bracing were derived from Street View from the heavy angle towers in Southampton, which all appear to be F72. (The angle towers at Romsey are similar but designed for a smaller angle.)

“GPO crossing” towers carry cradle guards suspended between the extended middle crossarms and the extra fourth crossarms; these offer enhanced protection for General Post Office (GPO) telecommunication lines against fallen conductors. Two D60 GPO crossing towers straddle Braishfield Road in Romsey and the diagram for this type is derived entirely from Google Street View as the schematic has not been recovered. Earthing arms were used for road crossings:

Earthing arms

Examples

Out of range.

Tower details

The height and clearances are obliterated from the D10 general arrangement drawing; they are instead taken from the earthing arms drawing covering D3 and D10. The tower height is thus an estimate only, as is the spacing between the peak and top crossarm. Base width is at ground level or top of stubs according to each drawing: they are not consistent.

The complete list of tower types is taken from National Grid’s drawing schedule for SWE SL2; the details for various types are not yet known.

See also

• “Pre grid pylons” album (Flickr)