Dolgarrog lines type

Contents

• Overview
  • General data
  • Progress
• Lines
• Tower forms
• Tower details
• See also

Overview

Two single-circuit 33 kV tower lines were constructed from Dolgarrog hydroelectric power station, one towards Colwyn Bay and one towards Minffordd substation just outside Bangor, Gwynedd. Geographer Alan Roberts noted against a photograph (see link under the header image) that the “line between Dolgarrog and Colwyn Bay [was originally] built in the mid 1950's to boost additional power to the newly erected 132Kv line off the National Grid from the hydro electric power station at Dolgarrog to the town of Colwyn Bay.”

Consultation of two Ordnance Survey maps puts the construction of both Dolgarrog lines between 1938 and 1949, but Tom Gloag notes that “many of these lines weren’t mapped by OS at the time”. The maps in question include:

• “Revision of 1913 with additions in 1938”, on which the line does not appear
• “Revision of 1913 with additions in 1948–49”, which shows the Caergeiliog and Dolgarrog lines

The maps show Dolgarrog to Minffordd as the only transmission line serving the Bangor area; exiting this substation was a line from Minffordd to Caergeilion on Anglesey (Ynys Môn). There is no sign of 132 kV lines at the time that the 33 kV lines were constructed.

By the 1950s, construction of single-circuit tower lines had appeared to have become an obsolete practice, as was putting 33 kV lines on steel towers; if this is indeed a 1950s line then it goes against both of those post-war conventions.

Nothing else is presently known about either line, such as the original owning organisation, the tower design contractor or the civil engineering contractor.

The towers do not appear to carry an earthwire, as with the earlier light construction towers in Scotland. However, they are designed to carry a pilot wire.

General data

Design contract	?
Found
Status	Historic, in service
Height (straight line tower)	?
Voltage	33 kV
Dates back to	?
Known conductors	?
Design conductor	?
Design earthwire	No earthwire
Circuit count	Single

Progress

Lines

The known lines are:

• Dolgarrog hydroelectric power station to Colwyn Bay (now wood poles at the Colwyn Bay end)
• Dolgarrog hydroelectric power station to Minffordd substation outside Bangor, now divided into:
  • Dolgarrog hydroelectric power station to Llanfairfechan
  • Bangor to a random location near Llanfairfechan

Further examination of Ordnance Survey maps is needed, but it appears that the second line originally ran from Dolgarrog to Bangor. The Dolgarrog end now diverts on wood poles to Llanfairfechan. The Bangor end now terminates in the middle of the countryside south of Llanfairfechan. Possibly it travels underground to Llanfairfechan.

Whether any other lines ever used this tower suite is also not known.

Tower forms

No material.

Tower details

No data.

See also

• Line tower, Bwlch y Ddeufaen, with the pilot wire fitted (Wikimedia Commons)
• Angle tower with earthing bar (Geograph)