RACA Journal June 2016 - Page 81

When quality matters Charel Marais Charel Marais is a quality, maintenance, commissioning and assurance manager for a consultant company in the HVAC industry. He undertook apprenticeship and qualified at Olifantsfontein training centre as a refrigeration technician and obtained an electrician certificate at the Metal and Engineering Industries Education and Training Board. He is qualified as a Professional Engineering Technician (Pr Techni Eng) and previously owned his own contracting company before moving into the consulting sphere. Charel’s goal is to make a difference in workmanship and equipment quality in the HVAC industry by sharing his knowledge with industry professionals of all levels. Don’t underestimate The importance of cable ties By Charel Marais Cable ties are such small, seemingly insignificant things but, if used incorrectly, they can cause major damage. C able ties were first invented by Thomas & Betts, an electrical company, in 1958 under the brand name Ty-Rap. Initially they were designed for airplane wire harnesses. The original design used a metal tooth and these can still be obtained. Manufacturers later changed to the nylon/plastic design. The design has over the years been extended and developed into numerous spin-off products. A cable tie or tie-wrap, also known as a hose tie, or zip tie, is a type of fastener used for holding items together, primarily electric cables or wires. Because of their low cost and ease of use, tie-wraps are rather ubiquitous, finding use in a wide range of other applications. The most common cable tie consists of a flexible nylon tape with an integrated gear rack, and on one end a ratchet within a small open case. Once the pointed tip of the cable tie has been pulled through the case and past the ratchet, it is prevented from being pulled back; the resulting loop may only be pulled tighter. This allows several cables to be bound together into a cable bundle and/or to form a cable tree. A cable tie tensioning device or tool may be used to apply a cable tie with a specific degree of tension. In order to increase resistance to ultraviolet light in outdoor applications nylon containing a minimum of 2% carbon black is used to protect the polymer chains and extend the cable tie's service life. Cable ties made of ETFE (Tefzel) are used in radiation-rich environments. Red cable ties made of ECTFE (Halar) are used for plenum cabling. Cable ties, however, are not designed to secure insulated refrigerant piping by supporting or keeping the suction and discharge lines cabled together. Cable ties cause extreme damage to Armoflex insulation and therefore must not be used to secure refrigerant piping. 2 1 1. The cable tie tool may cut off the extra tail flush with the head, in order to avoid a sharp edge which might otherwise cause injury. 2. Blue cable ties are supplied to the food industry and contain a metal additive so they can be detected by industrial metal detectors.> Continued on page 81 www.hvacronline.co.za RACA Journal I June 2016 79