Entity And Non-Incendive Concepts - ABB DHH805-A Operating Instruction

9.2.3 Entity and Non-Incendive component field wiring concepts
Entity Concept
Equipment which is FM approved for intrinsic safety may be
connected to the barriers based on the ENTITY CONCEPT.
This concept permits interconnections of approved
transmitters, meters and other devices in combinations which
have not been specifically examined by FM, provided that the
agency's criteria are met. The combination is then intrinsically
safe if the entity concept is acceptable to the authority having
jurisdiction over the installation.
The entity concept criteria are as follows :
— The intrinsically safe devices, other then barriers, must not
be a source of power.
— The maximum voltage (Vmax) and current (Imax) which the
device can receive and remain intrinsically safe, must be
equal or greater than the voltage (Voc or Vt) and current
(Isc or It) which can delivered by the barrier.
— The sum of the maximum unprotected capacitance (Ci) for
each intrinsically device and the interconnecting wiring
must be less then capacitance (Ca) which can be safely
connected to the barrier.
— The sum of the maximum unprotected inductance (Li) for
each intrinsically device and the interconnecting wiring
must be less then the inductance (La) which can be safely
connected to the barrier
— The maximum entity parameters Vmax, Imax, Ci, and Li
for the hand held communicator model DHH805A are
listed in paragraph 9.2.1 of this document.
— The entity parameters Voc or Vt, Isc or It Ca and La for
barriers are provided by the barrier manufacturer.
48 OI/DHH805-EN Rev. D | Handheld communicator Model DHH805-A
Non incendive Component Field Wiring concepts
The Non-Incendive field wiring concept is very similar to the
entity concept except it allows devices approved with Non-
Incendive Component Field Wiring parameters to be installed in
Division 2 hazardous classified location when connected to the
appropriate sources of power provided that the appropriate
criteria are met. The combination is then safe if the concept is
acceptable to the authority having jurisdiction over the
installation.
The criteria are as follows :
— There must be only one source of power. The source may
be an intrinsic safety barrier or it may be a device marked
with Non-Incendive Component Field Wiring parameters
suitable for connection to Non-Incendive circuit
components located in zone 2 hazardous location.
— The maximum voltage (Vmax) and current (Imax) which the
device can receive and remain Non-Incendive, must be
equal to or grater then the voltage (Voc or Vt) and current
(Isc or It) which can be delivered by the source of power.
— The sum of the maximum unprotected capacitance (Ci) for
each device and the interconnecting wiring must be less
than the capacitance (Ca) which can be safely connected
to the source of power.
— The sum of the maximum unprotected inductance (Li) for
each device and the interconnecting wiring must be less
then inductance (La) which can be safely connected to the
source of power.
— The Non-Incendive Components Field Wiring parameters
Vmax, Imax, Ci, Li, for the Hand Held Communicator
model DHH805A are listed in paragraph 9.2.2.
— The parameters, Voc,or Vt,, Isc, or It, Ca and La, for the
source of power are provided by the manufacturer of that
equipment.
9 Hazardous area considerations