NEC Code Amendments Lead to Significant Cost Savings
Exposed Run Code Information
NEC 2008 Article 725.154(D) hazardous (classified) location (2) and article 727.4(5) allow exposed run (ER) listed cables “to be installed exposed. The cable shall be continuously supported and protected against physical damage using mechanical protection such as dedicated struts, angles or channels. The cable shall be secured at intervals not exceeding 1.8 m (6 ft.).”
Cables that are UL 13 PLTC and/or UL 2250 ITC listed may also have an ER listing. These cables must pass the same crush and impact test applied to metal-clad cables, (UL 1569 crush and impact tests) but without the metal. Cables listed under UL 13 PLTC-ER meet the requirements of NEC Article 725.154(D), and cables listed under UL 2250 ITC-ER meet the requirements of NEC Article 727.4(5).
This provision can result in a great deal of freedom for installers and system designers and can result in significant cost savings over armored cables or cables installed in conduit.
Northwire ITC types GP(ER), RS(ER) and DB(ER) meet the NEC 2008 requirements and are UL listed as exposed run rated PLTC. Other Northwire Direct product lines featuring exposed run-rated cables are DataCELL® FIELD cables for FOUNDATION™ fieldbus, Profibus® DP, Profibus PA and HART-compatible cable.
The ITC Cable designation was added to the National Electrical Code in 1996 to meet contemporary demands for small-diameter, lower-cost cable for industrial and process control and instrumentation. The newer ITC specification is simpler to interpret than the older UL 13 specification for PLTC. The code change made it legal to use a wiring method that had been used effectively for years on offshore oilrigs.
Instrumentation Tray Cable is defined in Article 727 of the National Electrical Code. Cable construction and testing is described in UL 2250. Article 727 defines cable to be used for remote instrumentation and controls in industrial environments under certain conditions. Most notably, it is a cable designed with 300V insulation rating, but limited in use for 150V or less with a 5-Amp maximum current. Also the conductor is limited to sizes not smaller than AWG 22 and not larger than AWG 12. Please refer to the NEC, UL and other publications for more information.