CS-PL1

Contents

• Overview
  • General data
• Can be confused with
• Lines
• Tower forms
  • Examples
• Tower details

Overview

CS PL1 was the first power line contract to form part of the National Grid, using towers designed by Milliken Brothers. It is only known to have been used for two PL1 contracts: CS PL1 (Central Scotland) and SEE PL2 (South East England). It was followed by a revised design used for most of the other CEB PL1 contracts (not including MEE and SEE). [Standard Tower Types] uses the description “CS-PL1” for this type.

The 30° single and double circuit angle towers appear to have been used as part of the Milliken T169 33 kV tower series in Country Antrim.

Although the drawings included in the 1928 CEB annual report and in [Grid 1929] use standard tower type designations (S 2°, D 2°, S 10° etc), the Milliken Brothers drawings use an alternative nomenclature that can be found on the tower schedules, taking the form of a letter (A for 2°, B for 10°, C for 30° and D for 60° and terminal) followed by a digit indicating the count of circuits (1 for single circuit, 2 for double circuit). Both sets of type names are used here. Note that this creates an ambiguity in that “D2” could be double circuit (“2”) 60°/terminal (“D”), or double circuit (“D”) 2° line tower (“2”).

General data

Designed for	Central Electricity Board (CEB)
Design contract	Milliken Brothers L145
Found
Height (straight line tower)	66′–3″ (20.2 m) (A1 / S2) 78′–3″ (23.9 m) (A2 / D2)
Voltage	132 kV
Dates back to	1928 (drawings)
Known conductors	Single
Circuit count	Single, double
Normal span	900 foot assumed
Drawing ranges	L145

Can be confused with

• SS-PL1
• SEE PL1a
• SEE PL1(b)

Lines

Various lines have been found to date. A few are confirmed and detailed below:

Double-circuit lines confirmed so far:

• Charleston substation, Dundee, to Abernethy substation; from Grange to Errol the line has been diverted, using SEE PL1a towers.

Single-circuit lines confirmed so far:

• Bedford to Little Barford, believed to be SEE PL2
• A section of single-circuit towers starts at Abernethy substation in the direction of Auchtermuchty; this line now carries only 33 kV and changes to poles half-way between Abernethy and Auchtermuchty.

Tower forms

Milliken design as per the 1928 CEB annual report:

CS PL1 towers located near Kirknewton in West Lothian can be seen on Flash Bristow’s Pylons around the UK page.

It would appear that CS PL1 did not use transposition towers. There is also so far no evidence for a D10 (B2) type.

According to the enhanced tower bible, the SEE PL2 DT was a British Insulated design, although it closely resembles CS PL1 D60/DT. The tower is 72′–6″ tall with a 4 foot tall top crossarm. An alternative top crossarm, 6 foot tall, is also shown, with no explanation; the overall height is given as 74′–6″.

Examples

Tower details

See dimensions on the site guide page for a key to the tables.

Sources:

1. The construction of the “grid” transmission system in Great Britain [Grid 1929]
2. [Enhanced tower bible]

Crossarm spacing is top crossarm to middle crossarm and middle crossarm to bottom crossarm on double circuit towers, and top crossarm to bottom crossarm on single circuit towers.