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Cables as a fire hazard In construction, sometimes the cable jacketing is seen as a potential source of fuel for the fire. To limit the spread of fire along cable jacketing, one may use cable coating materials or one may use cables with jacketing that is inherently fire retardant. Teck cable or metal clad cables, may have exterior organic jacketing, which is often stripped off by electricians in order to reduce the fuel source for accidental fires. In Europe in particular, it is often customary to place inorganic wraps and boxes around cables in order to safeguard the adjacent areas from the potential fire threat associated with unprotected cable jacketing. All such mitigation methods are passive fire protection items subject to stringent bounding. Keeping critical cables operational during a fire Circuit integrity for cables is also established by using either inherently fire resistant cables, such as Mineral-insulated copper-clad cables, or by using boxes made of proprietary insulations, such as calcium silicate, vermiculite or perlite, intumescent and/or endothermic coatings or ceramic fibre or rockwool wraps for fireproofing purposes. Electrical circuits that may have to be kept operational during an accidental building fire include, but are not limited to emergency power circuits, such as those that power exit signs in a building, power circuits for operating rooms in a hospital, or the wiring that connects control rooms and nuclear reactors. All such mitigation methods are passive fire protection items subject to stringent bounding. The toughest of test methods known in the industry are those mandated by the US Nuclear Regulatory Commission, which came about as a result of the Thermo-lag scandal*. Interference Protection In applications powering sensitive electronics, keeping unwanted EMI/RFI from entering circuits is important. This can be accomplished passively with shielding along the length of the cable or by running the cable in an enclosure separate from any other wires which may induct noise. It can also be actively achieved by use of a choke designed to restrict the cables' ability to conduct certain frequencies. Types of cable Cables can be sorted into several categories and types. Generally it can by sorted into two main groups: Application Cable type Basic cable types are as follows: Basic Construction Based on construction and cable properties it can be sorted into following: Special See also | ||||||||||
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