Blaw Knox K1641

Contents

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

Overview

Many 110 kV single-circuit wood pole lines in Northern Ireland use flat formation, single-circuit lattice towers for deviation and termination. The SCT tower falls under Blaw Knox K1641 from the late 1940s, metricated as MK1641 in 1974; this type is also titled as “Northern Ireland 110 kV line / Contract N.I.624 / (Horizontally spaced conductors)”. The corresponding arrangement in Great Britain uses Blaw Knox K1420 angle and terminal towers.

Whether this type should be known as “Blaw Knox K1641”, “Blaw Knox NI624” or simply “NI624” (or “NI 624”) remains to be determined; “Blaw Knox K1641” has been selected based according to the convention of this website.

The designation “SCT” is listed in the [tower bible] but not depicted; towers of the same design exist at 132 kV substations, suggesting that these are simply de-rated 132 kV towers. On this site they are classified as 110 kV for convenience.

General data

Designer	Blaw Knox
Found
Height	?
Voltage	110 kV or 132 kV
Dates back to	1948 (drawings)
Conductors	Single
Circuit count	Single
Design conductor	?
Design earthwire	?

Lines

Widely used across Northern Ireland as angle and terminal towers on 110 kV single-circuit wood pole lines.

Tower forms

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

The expansion of “SCT” is not known. The design matches that of terminal towers, and there is no reason to believe that the “T” does not denote “terminal”.

The angle and terminal towers have been added based solely on Google Street View. The lower angle tower (used for at least 28° deviation) appears to be identical to the SCT from the front. The designations are not known, and the side views are omitted here. (The SCT material came from another source where this was the only the tower type on file.)

Tower details

Crossarm width is the total width across the single crossarm.