Blaw Knox K9906
Contents
Overview
Blaw Knox K9906 is a 66 kV distribution tower type. The Blaw Knox K9906 drawings were used for contract SWE SL11; the D30 at least was used on an SL4 contract. The details of these contract are not known. K9906 is depicted in [NSP/004/030] where it is listed as a “Knursling” type (intended to read Nursling, now a suburb of Southampton). The “Knursling” type has “Typical Tower Types in the family” “D3(s)”, D30, D60, DT and DTV. Northern Powergrid give the standard conductors as 100, 150 or 175 mm² ACSR with 60 or 70 mm² ACSR earthwire. The meaning of “s” in “D3(s)” is not known.
In addition to the Nursling area, the same towers can also be found in Gloucestershire. Whether both types share the K9906 designation is not presently known.
K9906 was superseded by L4(m) 66.
General data
| Design contract | Blaw Knox K9906 |
|---|---|
| Height (straight line tower) | 65′–0″ (19.8 m) |
| Voltage | 66 kV |
| Dates back to | 1947 (drawings) |
| Conductors | Single |
| Design conductor | ? |
| Design earthwire | ? |
| Drawing ranges | K9906 / XM2049 |
Can be confused with
- Baby PL16 (66 kV?)
- NWE SL4
- ca. 1945 standard 66 kV
- PL16 (D3)
- J L Eve C534 (D10, D30)
Lines
Lines discovered to date:
- Malton substation to Kirbymoorside substation, North Yorkshire
- Lydney substation to Ryeford substation in Stonehouse, both in Gloucestershire, England. The tower numbering is unclear. Tower ZLYD1 is at Lydney and numbering continues up to a junction to Lydney–Elton outside Hall Farm PV Substation. The line is then ZLYDA up to ZLYDA35 at Netherhills substation (the 37th tower). The line from Netherhills to Ryeford substation appears to be ZRYT numbered from the Ryeford end.
- A short line outside of Nursling, Southampton on a combination of K9906 towers and wood poles.
The Lydney and Nursling lines have been de-rated to 33 kV. The line at Lydney retains its 66 kV insulators except for the downleads on the terminal tower.
Two DTV towers can be found at Malton substation.
Tower forms
The following diagrams are shown to scale at 12 pixels per metre:
The GA&ED drawings for the terminal (DT) tower with sealing end termination omits the actual cable sealing ends, so these have been loosely approximated based on similar towers from other series.
Examples
The D10 tower is assumed to be such from the approximately 10–11° angle it carries; D10 and D30 are almost identical. All examples are in the Lydney woodland and were photoghraphed during pylon hunt 30, 6th July 2024.
Tower details
See dimensions on the site guide page for a key to the tables.
| Type | Source | Height | Base width | Crossarm width |
|---|---|---|---|---|
| D3 | XM2049-11 | 65′–0″ (19.8 m) | 10′–6″ (3.2 m) | 19′–0″ (5.8 m) |
| D10 | XM2049-12 | 64′–0″ (19.5 m) | 13′–6″ (4.1 m) | 18′–0″ (5.5 m) |
| D30 | XM2049-13 | 64′–0″ (19.5 m) | 15′–0″ (4.6 m) | 19′–2″ (5.8 m) |
| D60 | XM2049-14 | 64′–0″ (19.5 m) | 18′–6″ (5.6 m) | 21′–0″ (6.4 m) |
| D90 | XM2049-18 | 64′–0″ (19.5 m) | 21′–6″ (6.6 m) | 24′–6″ (7.5 m) |
| DT | XM2049-14 | 64′–0″ (19.5 m) | 18′–6″ (5.6 m) | 19′–0″ (5.8 m) |
| DTV | XM2049-14 | 64′–0″ (19.5 m) | 18′–6″ (5.6 m) | 40′–0″ (12.2 m) |
| Tower type | Peak to top crossarm | Top to middle crossarm | Middle to bottom crossarm | Bottom crossarm to ground |
|---|---|---|---|---|
| Line tower | 3′–6″ | 8′–6″ | 8′–6″ | 44′–6″ |
| Tension towers | 7′–0″ | 8′–6″ | 8′–6″ | 40′–0″ |
| Type | Limits |
|---|---|
| K9906 DT | Entry angle 0–5° |
| K9906 DTV | Entry angle 0–5° |



