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The back alleys are littered with super zap-straps

May 19, 2016
Various locking heads picked up in the alleys, with and without strapping

Deltec cable ties, with and without strapping, all dropped by Telus Fibre installers.

Crews employed by Telus are currently sweeping through the back alleys of Vancouver—their five year mission—to boldly string up reams of fibre optic cable, to carry the next generation of high-speed Internet and TV into the next generation of rental and condominium highrises.

Look up in almost any Fairview neighbourhood alley and you’ll see the black-sheathed fibre optic cable that Telus crews have attached along the line of B.C. Hydro wooden utility poles, just below the power lines.

And if you look down at the pavement, under the newly-installed cable, you may find curious and potentially useful remnants of the installation process, in the form of small, highly-engineered pieces of shiny black plastic, embedded with bits of metal and minutely embossed with the legend “T&B”.

If you are at all inclined to repair things then I recommend that you pick up any of them that you find.

The super-strong reusable cable tie that the pros use

A T&B locking head

A Thomas & Betts double locking head showing the two bronze teeth.

To secure the overhead fibre optic cable being installed throughout Vancouver’s back alleys, Telus contractors are employing some garden-variety one-use zap-straps but for the most part they’re relying on a special high-strength, reusable cable tie that only professionals—and especially professionals in the telecommunication industry—are familiar with.

These are Thomas & Betts brand double locking heads with Deltec straps. They’re made of acetal resin, aka polyoxymethylene, which is a thermoplastic characterized by high strength, hardness, rigidity and UV and temperature tolerance.

The heads have two slots, to accept Deltec plastic strapping. Each slot has a locking mechanism, consisting of a piece of marine-grade silicon bronze, that acts like a ratchet tooth and allows strapping to be pushed freely through in only one direction.

These two-part Deltec cable ties have a break strength of anywhere from 250 lbs. to 400 lbs. and they won’t scratch or cut other plastics like metal strapping will. And did I mention that the locking heads are reusable? Just cut the Deltec strapping and you can pull the two lengths all the way out and insert new strapping.

However, if you find any of these reusable and sturdy, all-weather locking heads left behind by Telus contractors, you’ll find them with only short, useless lengths of strapping or none at all. So what good are they?

You could buy new Deltec strapping, which goes for over $1.50-per metre or you could find a cheaper (read “free”) alternative.

To use these little heads, use your head and think outside the box

A double locking head works well with half-inch box strapping.

A double locking head works well with decently thick, half-inch box strapping.

Deltec strapping happens to be 12.7 mm wide (0.5 inches), which is the same width as the most common sort of poly (polyester/polypropylene/nylon) box strapping. I may not be able to find much Deltec strapping laying around but I can find metres of discarded box strapping, wherever fine cardboard boxes are shipped and received.

Poly strapping not only varies in width but also in thickness. In addition to being the right half-inch width, it has to be thick enough for the bronze teeth in the head to bite firmly, otherwise the strapping will be able to slide freely and uselessly back and forth.


If the poly strapping is the right width and thickness then it appears that it can substitute for the Deltec strapping to a large degree. The Deltec strapping may be stronger but the poly strapping (especially the polyester variety) has very high tensile strength and the teeth seem to lock it in place every bit as firmly as the Deltec.

As of this date (May 19) the Telus crews are busy in the alleys off Main Street, around 16th Avenue.

Given how I love zap-straps and steel hose clamps for the instant field repairs that they can effect on both my bike and my bike trailer, it should come as no surprise that I plan to follow in the footsteps of the Telus fibre optic crews, in order to score as many more of these remarkably strong and reusable locking heads as I possibly can.

And I would recommend that anyone else who’s handy with quick fixes should grab a few if the opportunity arises.

This is a once-in-lifetime opportunity to get rarely-seen professional-grade fix-it bits that could, conceivably, last someone a lifetime! Click the images to enlarge them.

  1. Rodney Clarke permalink

    I’ve long admired the prehensile strength of that ubiquitous yellow box strapping. You can rip it length-wise into much thinner strips to no particular end other than making a satisfying tearing noise, and it’s still ridiculously strong. Nice work on coupling it with the cast-off double-locking heads. Are the Telus crews moving to our ‘broadcast left’, in other words from west to east?

    • After they left Fairview, at least some of the Telus Fibre crews moved east. But I never thought to ask any of the installers how they were covering the city so I can’t say what they are all doing now. There are a lot of them but I don’t think there are enough to simultaneously cover an entire north-south band as they move east so they are probably moving side to side also (north-south-wise).

      I’m still finding the occasional head (which I’m now told the installers refer to as “saddles”) in Fairview. And I found one in a Shaughnessy back alley on Thursday.

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