Fire Inspector 1 Chapter 11 Electrical and HVAC Hazards Questions with Correct Answers

National fuel gas code - NFPA 54 National electric code - NFPA 70 The force required to move or conduct electricity is measured in units called - Volts Voltage Most houses are wired for - 110v and 220v The amount of electricity flowing through the system - Current The volume of electricity flow is measured in - Ampere (amps or amperage) Total electrical power that is available for use is a combination of the volts and the amps - Watt Electrical fires are caused principally by - Arching and overheating A high temperature luminous electric discharge across a gap - Arcing The two most commonly used over current devices - Fuses and circuit breakers An over current protective device with a circuit opening fusible part that is heated and severed by the passage of over current through it - Fuse The two general catergories of fuses - Plug and cartridge Typenof fuse comes in a wide varieties. They have round sockets that look like a lightbulb and the fuse looks like a plug that screw into the socket - Plug fuses Type of fuse available in quick acting and time delay type. Some are designed for single use only - Cartridge fuses Form of over current protection device where a switch is opened to stop the flow of electricity through the circuit - Circuit breaker Two specialized circuit breakers - Ground fault circuit interrupter ( GFCI ) and arc fault circuit interrupter ( AFCI ) Specialized circuit breaker that senses when current passes to the ground through any path other than the proper path. When this occurs it trips almost instantly , stopping all current flow in the circuit - GFCI Use for the same purpose in facilities where pipeline heating or deicing and snow melting equipment are installed . Intended to only protect equipment - Equipment ground fault protective devices (EGFPD ) Specialized circuit breaker that can detect the presence of arching faults . Intended to help prevent fires by disconnecting the individual circuits where great damage may occur - AFCI This helps electrical equipment by eliminating shock hazard by providing a path for stray currents and accumulation of static electricity to flow - Grounding A metallic underground water piping system must be used as the grounding electrode where it is available and where the buried portion of the pipe is more than how many ft long - 10' The two issues common to most generator installations - Protection of the fuel source and shock hazards associated with the generator Type of transformer uses air as a temperature maintenance mechanism and common in newer commercial facilities - Dry type transformers Type of transformer typically uses a type of oil to remain cool and are more common in industrial factories - Fluid filled electrical transformers If not installed outdoors , fluid filled transformers are usally required to be installed in a vault with how many hours of fire resistive construction and associated opening protection - 3 hours Widely used in the past and no longer available due to environmental concerns - Polychlorobiphenol ( PCB ) fluid Are round pipes that hold multiple wires in walls and ceilings - Conduits Narrow channels that hold wires and are threaded through walls and ceilings - Raceways The temperature of many common conductors and equipment in normal use - 167 F Extension cords should not be used to supply equipment that will load them beyond their rated capacity . True or false - True Points on the wiring system at which current is taken to supply utilization equipment - Outlets Found on boxes and cabinets, pre punched curricular holes - Knockouts The amount of water vapor or moisture held in suspension by gas or air expressed as a percentage of the amount of moisture - Relative humidity NFPA states that relative humidity between 30 and 65 % should be sufficient to provide a surface resistance of most materials that will prevent an accumulation of static electricity . True or false - True Relatice humidity should be as high as possible, even up to what % - 75 %