Blaw Knox T1648

Contents

• Overview
  • General data
• Lines
• Tower forms
  • Examples
• Tower details

Overview

T1648 is a 275/380 kV UK electricity pylon (steel lattice transmission tower) type designed for the North of Scotland Hydro Electric Board (NoSHEB), the operator of the non-CEB/CEGB portion of Scotland. Only a single drawing has been recovered, sheet 2 (upper portion) of the GA&ED for the minimum height line tower. Lines with T1648 line towers use angle towers resembling L2 and it appears that contract T1648 was simply for an enhanced line tower. This appears to have also been the case with L3 in Scotland: replacement line towers with improved clearances used in conjunction with the original angle towers. The corresponding L3 revised line towers were Blaw Knox T1521 (Blaw Knox) and C873 (J L Eve).

Compared to L2 D, T1648 D has greater vertical phase clearances and extended middle crossarms. The tower body is also noticeably slimmer than that of L2 D, and slimmer even than L8 D.

T1648 only appears to have been used at 275 kV. Drawing XM3693, from February 1961, is captioned “North of Scotland Hydro Electric Board 275/380 kV Double Circuit Lines Twin 0.4 sq.in. S.C.A. Conductors”, continuing the original intention that L2 would be a 257/380 kV type.

General data

Designed for	NoSHEB (North of Scotland Hydro-Electric Board)
Design contractor	Blaw Knox
Found
Height (straight line tower)	144′–3″ (44.0 m)
Voltage	275/380 kV
Dates back to	1961 (drawings)
Conductors	Twin
Design conductor	Twin 0.4□″ SCA
Design earthwire	?

Lines

Lines so far known to use T1648 line towers:

• Abernethy–Tealing (275 kV)
• Windyhill–Cruachan (275 kV)

Tower forms

The following diagram is shown to scale at 12 pixels per metre:

The verified (solid line) portion of the image is from Blaw Knox drawing XM3693/2F, tower type DM.20 (minimum height). The remaining steelwork (dotted line) is drawn per Google Street View imagery.

Examples

Tower details

Crossarm width is the total width across the widest crossarm pair, measured between the centres of the conductor attachment points rather than to the end of the steelwork.