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WARNING – Explosion Hazard
INDEECO strongly recommends installation be performed
by qualified personnel familiar with the National Electrical
Code and all local codes and standards regarding
explosion-proof equipment. It is the responsibility of the
installer to verify the safety and suitability of the
installation.
Per Article 500-516 of the National Electrical Code, a
hazardous area is defined by a "Class", "Division", "Group",
and "Temperature Code". The Class can be I or II, where
Class I indicates that the hazard classification is due to the
presence of an explosive vapor. Class II indicates an
explosive dust. The Division can be either 1 or 2. Division
1 indicates a hazard is ALWAYS considered to be present.
Division 2 means the hazard is only present under abnormal
conditions. The Group defines the explosiveness of the
hazard. The Temperature Code specifies the temperature
at which a hazard will ignite.
INDEECO can provide designs suitable for all of the above
conditions, but a heater should never be placed in an
environment not noted on the heater nameplate.
NEVER operate the heater in an atmosphere with an
ignition code temperature LOWER THAN the nameplate
rating. The user must determine the actual area
classification.
Special design considerations for electric circulation heaters
used in hazardous locations:
1. Locate all electrical connections in an appropriate
enclosure.
2. Prevent surface temperatures of the heater from
exceeding the design ignition temperature.
INDEECO Circulation Heaters designed for Division 2
locations are provided with Nema Type 4 enclosures unless
otherwise specified, since the terminal box is free of arcing
or sparking devices. Heaters designed for Division 1
atmospheres are provided with an enclosure designed to
contain an explosion.
When the design temperature of the process exceeds the
rated ignition temperature, it is critical that the heater and all
customer piping is properly insulated.
HAZARDOUS AREAS
(where applicable)
INDEECO
425 Hanley Industrial Court
St. Louis, MO 63144
Phone: (314) 644-4300 Fax: (314) 644-5332
www.indeeco.com
5
A hazardous area heater must be powered and controlled
by a heater control panel designed to provide necessary
over-temperature safety interlocks. Contact INDEECO if
assistance is required to properly control and protect the
heater.
Never apply power to a heater in a hazardous atmosphere
unless all terminal box covers are properly installed with all
cover bolts.
All conduits entering the heater terminal box must be sealed
within 18" of the heater using an explosion-proof conduit
seal. Any unused openings must be properly sealed with a
steel pipe plug. Follow the NEC for specific conduit
requirements such as the requirement for Rigid Conduit.
To ensure proper flamepath, all threaded conduits must use
rated fittings and be tight, with a minimum of 5 good threads
engaged. Any machined metal-to-metal surfaces on
terminal boxes must be handled carefully to prevent
scratches which may void the explosion-proof rating.
WARNING - Risk of Explosion
Operating the heater at a voltage higher than the
nameplate value may result in elevated
temperatures and amperage above the design
ratings.
Heaters used to heat explosive products such as methane
at a temperature above their ignition temperature must
remain free of oxygen.
Proper grounding of equipment in hazardous areas is
critical to eliminate potential sources of sparking.
Replacement of electrical components should only be done
by authorized personnel familiar with the requirements of
maintaining electrical equipment in an explosion-hazard
area.
35-2150-83-4
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