Ronald Petersen
Ideal Industries Inc.
Problem
If installers use a cable lubricant that is incompatible with cabling materials being used, it can damage the wire or conduit. For example, some specialized cable jacket materials, particularly low-density polyethylene and semiconducting insulations and shields, may be damaged if the wrong cable lubricant is used.
Solution
It is important to choose a cable lubricant that is compatible with the cable materials being used on the job. To match the most suitable product to the job, you should also know the type of cable pull and the properties of the lubricant (see "Cable lubricants serve as inexpensive insurance for cable pulling," June 1996, page 6). Lubricants can be thick or thin and are available as pastes, gels and pourable gels. Sometimes installers determine the viscosity (resistance to flow in a fluid) based on the characteristics of the cable pull, and sometimes they select lubricants by personal preference. However, you should consider five main properties and issues when selecting a cable lubricant: compatibility, safety, lubricity (how well it lubricates the cable), adherence and stability.
Procedure
For data communications and telecommunications applications, use polymer-based lubricants, which are essentially water-based and designed not to harm the cable jacket.
1) For optical-fiber applications, however, polymer- or silicon-based products are recommended because this cable requires a thinner, more slippery lubricant that stays on the cable.
2) Do not use lubricants designed for use with electrical wire. For example, if you use some oil- or wax-based emulsions on low-density polyethylene, the cable may swell. And if you then pull the cable around a bend, stress-cracking can occur.
3) Ensure that the cable lubricants you use contain no harmful ingredients and are safe to handle. They should contain no materials that irritate the skin.
4) Make sure that the cable lubricants you use are nonflammable. Also, you may want to check if the product is odorless, as a matter of preference.
5) Use a lubricant with a low coefficient of friction, which determines the lubricity of the product. The lower the coefficient of friction, the less resistance there is during the cable pull, and the easier it is to do the job.
6) Check the lubricant`s adherence--how well it clings to the cable, and how well it coats the conduit during a pull.
7) Look for a product that stays soft after a cable pull.
8) Consider the product`s stability, or the lubricant`s tendency to break down or deteriorate over time. For example, some lubricants will dry to form a hard mass, making re-entry into a conduit difficult once the lubricant has set. Cable removal will also be difficult if there is no residue of lubricant.
Ronald Petersen is senior product development chemist at Ideal Industries Inc., Sycamore, IL.