NEC Article 725: requirement or loophole

It is argued that Article 725 is one of the less obvious but powerful sections of the National Electrical Code. This article covers remote-control, signaling, and power-limited circuits that are not an integral part of a device or appliance. The limitations imposed and the advantages provided by the section are discussed. Application in conjunction with hazardous environments is presented. The installation, application, and transient protection of communications cable for instrumentation circuits is outlined. It is concluded that use of power-limited circuits with intrinsically safe equipment significantly reduces the complexity and cost associated with hazardous environments and inexpensive communication cable can be used for power-limited controls. Direct burial cable makes possible excellent performance and wide bandwidth. Lightning and transient protection can be very effectively implemented. Installation is simple and reliable