Hazardous
When Was Article 505 included in the NEC
1996
How Often is the NEC revised
every 3 years
how many Parts in article 100
Zero
The temperature at which a combustible liquid gives off vapor in sufficient concentrations to form an ignitible mixture with air near the surface of the liquid is at or above ? and below ? .
100 & 200
Areas where pyrophoric materials are the only materials that are handled or used are ? .
outside of article 500
Refrigerant machinery rooms containing ammonia refrigeration systems are permitted to be classified as “unclassified” locations if they have adequate mechanical ventilation that operates continuously or if the mechanical ventilation is initiated by a detection system when the ammonia concentration exceeds ? .
150 PPM
Class II, Division 2 location where combustible dust accumulations on, in, or in the vicinity of electrical equipment could be sufficient to interfere with the safe ? the equipment
dissipation of heat from
Class I equipment shall not have any exposed surface that operates at a temperature in excess of the ? of the specific gas or vapor.
autoignition temperature
Equipment that depends on a single compression seal, diaphragm, or tube to prevent flammable or combustible fluids from entering the equipment shall be ? for a Class I, Division 2 location
Identified
Cables with a gas/vapertight continuous sheath capable of transmitting gases or vapors through the cable core shall not be required to be sealed except as required in 501.15(E)(1), unless the cable is attached to process equipment or devices that may cause a pressure more than ? to be exerted at a cable end.
1500 Pa
Motors, generators, and other rotating machinery are permitted to be installed in Class I, Division 1 locations, if they are of the totally enclosed inert gas-filled type supplied with a suitable reliable source of inert gas for pressurizing the enclosure, with devices provided to ensure a ? pressure in the enclosure and arranged to automatically deenergize the equipment when the gas supply fails.
Positive
An intrinsically safe circuit is one in which any ? is incapable of causing ignition of a mixture of flammable or combustible material in air under prescribed test conditions.
Spark or thermal effect
A control drawing is a drawing or other document provided by the ? of the intrinsically safe or associated apparatus
The manufacturer
Zone 0, Zone 1, and Zone 2 atmospheres containing acetylene, hydrogen, or flammable gas, flammable liquid-produced vapor, or combustible liquid-produced vapor mixed with air that may burn or explode, have either a maximum experimental safe gap (MESG) value less than or equal to ? or minimum igniting current ratio (MIC ratio) less than or equal to 0.45 are included in group IIC.
.5 mm
An area in which equipment is operated or processes are carried on, of such a nature that equipment breakdown or faulty operations could result in the release of ignitable concentrations of flammable gases or vapors and also cause simultaneous failure of electrical equipment in a mode to cause the electrical equipment to become a source of ? , would be classified as Zone I.
ignition
Flammable gas detection systems equipment used in restricted industrial establishments shall be ? for Zone 1 and for the detection of the specific gas or vapor to be encountered.
Listed
Classification of areas, engineering and design, selection of equipment and wiring methods, and installation and inspections shall be performed by ? .
qualified persons
Electrical equipment, for use in Zone 0, Zone 1, and Zone 2 locations, that is designed for use in a range of ambient temperatures other than ? is considered to be special
−20°C to +40°C
PVC or RTRC conduit is permitted to be used in Zone 1 locations where encased in a concrete envelope a minimum of ? thick and provided with not less than 600 mm (24 in.) of cover measured from the top of the conduit to grade. RMC or IMC conduit shall be used for the last 600 mm (24 in.) of the underground run to emergence or to the point of connection to the aboveground raceway.
2"
Electric submersible pumps with means for removal without entering the wet pit shall be considered portable utilization equipment. The extension of the flexible cord within a ? raceway between the wet-pit and the power source shall be permitted.
suitable
Overload devices for increased safety “e” motors used in Zone I locations shall be selected to trip or shall be rated in accordance with the ? of the motor and its overload protection.
listing
Zone 20, Zone 21, and Zone 22 locations shall be classified on the basis of the properties of the combustible dust, combustible fibers/flyings, or ignitible fibers/flyings that might be present, and the likelihood that a ? concentration or quantity is present.
Combustable or ignightable
For equipment involving sources of optical radiation (such as laser or LED sources) in the wavelength range from 380 nm to ? , the risk of ignition from optical radiation shall be considered for all electrical parts and circuits that might be exposed to the radiation, both inside and outside the optical equipment.
10 µm
Type of protection for electrical equipment that uses the technique of guarding against the ingress of the external atmosphere, which might be explosive, into an enclosure by maintaining a protective gas therein at a pressure above that of the external atmosphere is ? .
pressurized enclosure “p”
The dust ignitionproof protection technique is permitted for equipment installed in Zone 20, Zone 21, and Zone 22 locations for which it is ? .
Ignitable