Inquiries for wire mesh pulling grips come in from all over the place, and it’s interesting to see how local tradition will affect terminology.
The length of a grip depends on where you’re standing. If you’re reading a North American catalog, the length of the mesh is taken at the grip’s nominal diameter. That is: it’s measured when it’s fitted around the cable it’s pulling. This is the engaged length of the grip; the eye and the overall length are measured separately.
Other locales will measure the “free length” of the grip, when it’s hanging on the wall. The free length can be half-again as long as the fitted length, so it’s not a clear indicator by itself of the size of the grip in service. The comparison below shows the difference: a free length of 35″ can contract the mesh to just 21″ when it’s installed.
The wire weave of a pulling grip is flexible, and the grip will contract as the tube diameter increases. Variation of a couple inches in the free length is typical, and the fitted length will vary depending on the actual diameter of the cable.
We’ve added a new feature to the website and incorporated a poll question on the main page. Take a moment to plug your preferred projectile for line blowing: foam, parachute, cone or grocery?
Results will be tallied by month-end.
Pardon the pun, but how often do you get to say that in public?!
We’ve got a range of line-blowing products on special this month – mix and match to build a tool kit that works for you! All projectiles are available individually or as kits, in a variety of sizes and weights: from durable Line Darts to our unique Ultralight Birds and Parachutes.
Start with a high-pressure Control Valve that fits to your compressor, or choose the DCD Power Blower for a powerful self-contained unit. Both options have their advantages.
The Control Valve uses twist-lock fittings to mount to a standard air hose, and mounts to threaded Innerduct Seals for a secure, air-tight seal. Larger ducts can use the advanced Duct Seal Body with quick-change polyurethane Seal Kits.
The inner bore of the Control Valve is smoothed to ensure that nothing can get hung up midway through the job. Our Valve also comes complete with three different rope guides – others don’t!
The Power Blower is a portable unit with parallel, twin motors to provide the maximum pressure available in this class of line blowers: up to 30% higher than the competition. The motors are individually fused and switched, so use one motor when that’s all you need or both when you’ve got a 30 amp breaker at your disposal!
Check out the whole range of Line Blowing Equipment here and follow through with pulling twine and Bull-Line pull tape!
It’s a fairly regular request we get these days, “I’m wondering if I should service my swivel. What should I look for?”
Servicing the equipment you have is bound to be cheaper than buying new – in most cases! – and we’re seeing a lot of planning ahead this season. Things are tight; no one needs a surprise.
I’ve previously summarized what’s involved in swivel maintenance. This time, I’ve taken advantage of one of these on-line resources to boil it down to a step-by-step instruction on maintaining your Maxi DUB-Swivel.
Forward the link along to your crews so they can take care of their gear; and as always, give us a call or your local DCD distributor if you have any questions.
If you want to get your swivel factory serviced, we can do that too. We have the tools and material to return your swivel to prime condition. We built it; we can rebuild it!
Installation can be rough on a new electrical cable! A pulling winch can apply a few thousand pounds of tension. Bends in the duct can apply crushing sidewall pressure. Even the pulling eyes can chew through the cable jacket and permanently damage the cable ends. Cable manufacturers have a variety of physical limits for different cable constructions (tension, bending radius limits, end connections, etc).
Cable manufacturers limit the pulling force of wire mesh grips to a few hundred pounds for a reason: the wire mesh is gripping on the external plastic jacket of the cable. But you can’t expect the plastic jacket and rubbery insulation to support a structural load!
Typically, cable manufacturers require 10-15 feet of cable be cut away, beyond the end of the wire mesh grip. Why? Because the pulling forces exerted on the outside surface have applied shear forces through the jacket, the insulation and the outer strands of the cable construction – there is no way to ensure that the cable construction has not been damaged or deformed during the pull.
To take advantage of the cable’s maximum pulling tension, you have to get a grip on the conductor itself. The DCD Power-Grip is designed to lock onto the conductor strands and the harder you pull, the tighter your Grip! When you’ve completed your pull, cut away the portion of the cable conductor deformed inside the Power-Grip and that’s it.
Setscrews are used in a number of applications to clamp parts together: end fittings to fiberglass duct rod, fiber optic strength members, and electrical conductors into pulling eyes, for example. They’re a quick, simple and relatively strong connection, so long as you turn the wrench with some care.
Duct rodders can be spliced or ends replaced with new fittings – the setscrews can bite right into the fiberglass core to ensure a solid material interlock, or you can apply a redundant coating of glue.
Another application is our multiplex pulling eyes: three setscrews are used to clamp the free end of the each conductor into a pulling eye, for short, straight pulls of moderate tension.
However, the clamping force developed by the setscrews can’t be considered an exact science. The copper strands will shift as the setscrew descends, moving strands aside to fill the remaining bore space. But they may randomly shift to one side as the screw turns down, or they may not shift and just ovalize the conductor.
Fixed torque values are difficult to define for these somewhat random events! Practically speaking, “as hard as you can” works out to be a fairly comprehensive instruction for the guy turning the wrench.
DCD Design’s Power-Grips and Swivel-Grips are designed to make cable installation easy and secure. The re-useable Grips are sized to fit electrical cable from 1/0 through 2000MCM and really shine for the larger cables, where the pulling tension will approach the cable manufacturer’s allowance.
Assembly of the Power-Grip to the electrical cable is quick and easy: cut back the insulation to bare the conductor; mount the Threaded Cone Nut to suit the conductor size; screw in the Tapered Insert; and mount the preferred attachment Body. You select which Body suits your connections: the Lug, Clevis or Swivel Bodies share common threads to quickly mix and match.
The Power-Grip locks onto the conductor strands and the harder you pull, the tighter your Grip! When you’ve completed your pull, cut away the portion of the cable conductor deformed inside the Power-Grip and that’s it. You’re ready to re-use the Grip for the next conductor.
Last week’s presentation of Tube-Lube 326 to the attendants of the Western Underground Committee’s January meeting went really well, with the support of the WUC Executive, San Diego Gas & Electric, and Pacific Utilities. A thirty minute PowerPoint presentation was followed up with a walk outside to have a look at SDG&E’s cable pulling trailer.
Two main points emerged from conversations through the afternoon and into the evening’s “Table Talk” session:
1) An environmentally responsible lubricant option generates a lot of interest! A cable pulling lubricant that’s water-based and chemically inert protects your workers on the site, the natural environment surrounding the site, and the installed cable throughout its lifespan.
2) A water-based lubricant doesn’t require a thick surface coating on the cable to do its job. Less thickness per square inch means you’re using less, and a 5-gallon bucket can go two to three times as far as a thicker lubricant. You save money by getting more miles per gallon.
Tube-Lube can also be applied with built-in nozzle sprayers, so the installation crew is doubly protected: besides a nearly blank MSDS sheet, the crew can stand back from the cable under tension and adjust the application from the other end of a twenty-foot hose extension – outside the vault entirely!
Fortunately the weather in Tucson cooperated – we were between the weather systems that deluged on the Southwest through last week. And I took the scenic route down the Pinal Parkway, and one detour up Redington Road into the Santa Catalina range. Saguaro, tumbleweeds, and dust storms!
Apparently Phoenix doesn’t get a lot of rain. That’s what the locals say. They’re supposed to get 5 inches this week – about as much as they got all of last year! Impressive statistic, but I’m from Vancouver, Canada. These grey skies and blustery winds are not so unusual! And it’s warm too.
Unfortunately they did have to close the airport, so I’ll be spending an unexpected day in friendly Phoenix!
The WUC meeting in Tucson was a great success, by the way. I met a lot of great characters, and the presentation on Tube-Lube was very well received – I’ll thank my audience for being so receptive!
We enjoyed a demonstration of Tucson Electric’s Boomer-Dawg winch and had a look at San Diego Gas & Electric’s cable pulling trailer under clear afternoon skies. I’m glad they were able to bring it out to Tucson. The evening “table talk” with Pacific Utilities went well, too!
Hopefully, the storm will blow through tonight and I’ll be on my way home tomorrow. See you next week!
“Hablas espanol?”
“Parlez-vous francais?”
“Sprechen sie deutches?”
“Вы говорите по-русский?”
“你讲中文?”
“هل يتكلمون العربية?”
We added a new feature to the DCD Design website today: instant page translations powered by Google Translate!
Check the left-hand bar of any product page; choose your preferred language; wait a moment to translate. Granted: it’s not a perfect translation, but it gets the gist across!
If you need more, use our Comment page to send a note, and we can find tools to translate your questions.
