A new market for electrical devices is now emerging for UL-approved cables, plugs and connectors to provide temporary wiring in convention centers, trade exhibitions, entertainment events and film locations. A major factor is the importance of safety (i.e., secure cables and power connecting devices). These locations have special requirements to meet the often rough handling and varying wear conditions associated with trade shows. Cables are laid down in high-traffic areas where people walk on them and forklifts drive over them in exhibition centers.
For years these temporary wiring locations have been served by flat wire festooning cables and with standard plugs and connectors designed for UL-approved round cables. Flat cable has been used to allow the installation of the cables under carpets to prevent injury when someone steps on the cable. The plugs and connectors available to date, however, were not designed to effectively terminate flat cable. Without a UL standard for this specific application, the methods used to temporarily wire a trade show have not been very safe.
Today, however, largely as a result of pressure from the National Fire Protection Association and the Consumer Product Safety Commission, new codes and standards have been developed for products in these applications. Before 2001, no listing existed for flat cable, but on Dec. 1, 2001, a new UL 2305 standard, “Exhibition Display Units — Fabrications and Installation,” was issued. UL has also established a separate “XNRW” category for Exhibition Display Units, Attachment Plugs and Cord Connectors of the Assembled-on Type. Thus, at the moment, several manufacturers have submitted and obtained approval on three-wire flat cable with plugs and connectors molded directly on to the cable, but no four- or five-wire flat cable or plugs and connectors have been approved. At least one manufacturer has submitted a five-wire cable and is awaiting UL approval. As soon as the cable is approved, plugs and connectors will also be submitted for approval. In the next six months, products that meet the new standard will be readily available.
The new UL 2305 standard specifies tests that consist of strain relief, cable pull and flexing, mold stress, roller flexing, dielectric and abnormal cycling temperature. Features of the products that will pass these tests include cables with heavier insulation, and plugs and connectors that are designed to clamp directly and securely to flat-wire cables.
Therefore, when enforcement of approved codes begins, a market for these new products will be established resulting in improved safety, connector reliability and eliminated loss time from failed connections.
Now and in the past, exhibition customers were limited in their choice of plugs and connectors by what they could find to secure trouble-free electrical service in these applications. Terminating flat cables with conventional round cable devices has never been easy, requiring “special techniques” that can violate code. Once plug and connector manufacturers modify their products, submit them for testing and receive UL approval, there will be a readily available source of supply for these products. Finding matching UL listed devices may not be easy, however, since most manufacturers are not prepared for this new standard. Local compliance may also lag behind.
Guru Arora is manager of engineering services and Arthur Hansen is a technical product manager for Cooper Wiring Devices, Long Island City, N.Y.