The Fleet Business Authority
Issue link: http://heavydutytrucking.epubxp.com/i/221397
Trailers o PHOTO BY TOM BERG things you should know about trailer lighting and wiring A walk around a truckstop on a cold night revealed lots of engines idling and most lights turned off. Of those that were on, all LED lamps were operable with not even one diode burned out. What if an inspector found some, though? Over the years, electrical failures have been the number one problem with trailers. Lighting problems have been reduced by the wider adoption of LED lighting. However, even LEDs, along with the rest of the electrical system, are subject to corrosion, which remains a major headache. Aggressive de-icing chemicals that are splashed up onto trailers' undersides and onto wiring and lamps, speed up the corrosion that interrupts current flow. The best way to avoid the worst of these problems is by taking a "wholesystem" approach when spec'ing new trailers, says the Technology & Maintenance Council of the American Trucking Associations. Proper maintenance of the system, including replacement of LEDs when some of the diodes fail, is still your best bet for staying safe and avoiding points against your CSA score. 1 A whole-system approach is best Recently revised recommendations from TMC say the electrical system should include sealed wiring, water- and corrosion-resistant connectors and low-amperage lamp designs. They are the things to get for long life with few troubles and low downtime, says Recommended Practice 704C. project, Brad Van Riper, chief technology officer at Truck-Lite Inc. The rewrite: • Made the RP light-source neutral, and eliminated bulb types and ratings to allow for technology improvements; • Removed and replaced obsolete references; • Updated lighting locations; and • Added wiring harness information, "focusing on the system," he says. "The purpose of the RP is to help equipment purchasers specify a safe and effective heavy-duty lighting system that is low-maintenance, durable and corrosion-free for a minimum service life of 12 years," Van Riper explains. Twelve years is a duty cycle agreed on by task force members as typical for widely used trailer types, especially dry freight vans. "Since lighting is moving away from incandescent light sources and more toward LED technology, the committee decided to de-emphasize the bulb and look at the complete system. We believe that the light source is no longer the weak link in the system, and teaching fleets to focus on a quality system will improve the durability and reduce maintenance on their new trailers." RP-704C provides guidelines for how a trailer's electrical system should be spec'd, and refers often to standards set by the Society of Automotive Engineers, Truck Trailer "We believe that the light source is no longer the weak link in the system." – Brad Van Riper,Truck-Lite That's not new advice, but it's newly included in the RP, whose "C" suffix means it's the third update. "RP-704B, the Recommended Practice for Heavy-Duty Lighting Systems for Trailers, was last updated in January 1992 and was badly in need of an update," explains the leader of the Manufacturers Association and others. And it leaves room for various trailer types and applications. "As you'd probably guess, there are as many wire harness systems as there are applications," Van Riper explains. "A 'quality system' is one that meets the needs of the end-use customer." Tom Berg • Senior Editor 62 HDT • DECEMBER 2013 www.truckinginfo.com