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Poles
 The dark brown wooden pole supporting telegraph or transmission
lines is as much a part of the British countryside as the
hedgerows themselves. They have been used for this purpose for
over a hundred years and some of the original poles are still in
service. People accept the 'telegraph pole' as a natural element
of the landscape, for indeed it is, being not far removed from the
original tree trunk from which it came.
In spite of the passage of time, nothing yet has been developed
which can satisfactorily replace the simple pole for it's
aesthetic appearance, functional efficiency and long life. It
remains the most economical way of supporting overhead lines,
which are themselves the most economical transmission method. We,
at Calders and Grandidge, are the main supplier of poles in the UK
and our strategically placed depots are fully equipped to process,
preserve and stock the large number of poles needed to serve UK
and overseas markets.
Responsibly made
The primary species used for poles in the UK is Scots Pine (pinus
sylvestris) imported from Scandinavia. Our quality control begins
in the exporting country, where, after felling, each log is
inspected by a Calders & Grandidge expert to ensure that it meets
both our own standards and those of our customers.
A pole, when it arrives at our depot, is only partially seasoned.
Seasoning takes from six to twelve months, according to the size
of the pole, and must be scientifically checked to ensure that the
moisture content has been reduced enough for it to undergo
preservation treatment. We normally have about 70000 poles in
stock at all stages of seasoning prior to preservation.
 Before a customer can take delivery of a pole it has to go through
a number of processes.
Firstly the outer layer is dressed off. Then, depending on the
customers requirements, notches are cut for cross arms and bolt
holes are bored. The shape and position of these can vary for each
pole in a transmission line. We carry this work out in one of two
ways. For poles with non-standard requirements, our highly skilled
craftsmen do the work, using power tools, to position the holes
and shape the notches exactly as required.
They also cut the poles to length and shape the top. Finally, they
carve identifying marks into each pole.
For standard poles we use our specially developed processing
machine. This is 240ft long and, using fully mechanised
techniques, dresses the poles, bores holes and cuts poles to
length, making the process all under the control of one man.
The pole is then ready for preservation. This is achieved using
impregnation under pressure. The pressure vessels, the largest of
which is 2 metres in diameter and 36 metres long, are filled with
one of two alternative preservatives. Creosote which produces the
familiar dark brown poles or CCA, which is a green water borne
copper/chrome/arsenic composition.
Each preservative meets the relevant British/European standards.
The effectiveness of these preservatives is evidenced by the
intended minimum life expectation of a pole of 40 years. Most last
far longer than this.
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Sleepers & Utilities
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