The Pot-Head
Key distinguishing points
- Internally threaded
- Single or Double wire groove
- Screw lid fitted on top.
- Predominately white / cream in colour
- black composite also made
- Used all over the country by the railways and GPO
3 Terminators..
Left to Right : Taylor Tunnicliffe, (LMS) ; Black composite with BR moulded inside top and a Bullers No.16 GPO double groove, 1970
Left - Taylor Tunnicliffe. Center - Black No.16 with BR(W) impressed mark. Right - Bullers No.16 in ceramic.
Some terminators were fitted with a fuse link to allow easy sectorisation of a line and provide protection across sections without the need for a cable to be dropped down the pole into a fuse box. No example exists within the collection, although I am sure a example is not far away.
And 3 lids -
Left - Unknown mark 'E'. Center - British Rail (Western Region). Right - General Post Office
A Large TTC terminator ?
A large Taylor Tunnicliffe example has come to light, stamped 'Patent No. 295?-01 Reg No. 563022-520335. This unit is incomplete but certain dimensions can be ascertained. The Diameter is 79mm and made with a 5/8" thread. A large cap is also needed as the thread diameter has increased by 5mm to 65mm. If the height were to increased by the same ratio, we could expect it to be approximately 116mm high.
Standard TTC top view and larger TTC top view with patent number on rim.
Very Large Bullers No.16
This Bullers variation of the double grooved pothead is considerably larger in diameter than a conventional No.16 and probably has its own designated number. A faint bullers logo is visible on the front along with P.8411, most likely a pattern number.
As can be seen from these two top views, this insulator is a good bit larger, diametrically, than the standard No.16
Hole spacing, internal depth, thread pitch and pin size seems to remain unchanged, it's just larger!
Latest find
This appears to be a fragment of a normal pothead insulator except it is not. The most obvious difference is the large wire groove across the top and a thin rounded ridge below the threads.
Normally the lid would seat down upon a flat ridge and form crude seal but in this instance the thin ridge appears to be a wire groove ridge and maybe the lid was more of an overall cover.
This superb pothead screw lid was recovered by Tris Horton early in 2005. It's obviously of LMS origin and is unusual in having the date impressed as well, 1925. A clear Taylor Tunnicliff logo proclaims its supplier.
