© 2010 Jonathan Swain. All rights reserved.

Pull thru

According to my trainer, a Cable Pull Through is a harsh exercise involving a column of weights. Gavin says that it’s a bit embarrassing to do in the gym, but that nothing is better for firming up the hams. In the communications industry a Pull Through is the term used to describe the process of dragging cables along underground conduit, a procedure that has been carried out in metropolitan areas for at least 50 years. The conduit offers physical protection for the cable and the possibilities of expansion without further digging. Replacing cables or adding a new cable can be done in two ways. For short distances, pulling the cable either by hand or a winch mechanism is preferred. In the fibre optics industry, with thinner, lighter cabling, pulling is being replaced by using compressed air to blow cabling along the conduit. Both methods require the engineer to take into account the length and weight of the cable, whether the conduit bends, how often, whether up or down, what materials the pipe and the cable jacket are made from, whether there are other cables already in the conduit, and which lubricants are used. Originally tallow, a lubricant made from animal fats, was favoured. This was superseded by a petroleum based chemical lube. Some engineers say a lubricant used in cattle breeding and on stud farms seems to work best.

published in TicToc8, January 2011

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