CMC TECHNICAL REFERENCE MANUAL
1X36003 Version 2.52
1996-1999 Ingersoll-Rand Company
Date of Issue: 18-Oct-1999
73
Space Heater
Required for NEMA 4 and NEMA 4X panels to protect the panel from internal condensation.
This option should also be used with NEMA 12 for unheated building applications.
Vortex Tube Cooler
This panel cooler is required on NEMA 4 and NEMA 4X enclosures to maintain the operating
temperature below the maximum. An adjustable thermostat is provided to open and close a
solenoid operated valve from the instrument air header in the panel. The cooler works by
converting filtered compressed air into a hot air stream and cold air stream. The hot air
stream is vented external to the enclosure and the cold air stream is directed into the
enclosure.
Type Z Purge
The CMC requires a Type Z Purge when the customer environment is Division 2. A Type Z
Purge reduces the classification within an enclosure from Division 2 too non-hazardous.
When provided, a NEMA 4 or NEMA 4X enclosure is required. Hand valve selectable quick
and slow purges, with flow meters are provided to regulate the amount of gas entering the
panel. A differential pressure switch is wired to a light on the front of the panel to indicate if
there is a loss of purge gas. A relief valve is installed to prevent over-pressurization and a
warning label, text below, is affixed to the front of the panel.
WARNING
Enclosure shall not be opened unless the area is known to be non-hazardous
or unless all devices within the enclosure have been de-energized. Power shall not be
restored after the enclosure has been opened until combustible dusts have been
removed and the enclosure re-pressurized.
Fused Control Power Disconnect
As a safety precaution, this option removes power from the panel before the door is opened.
By turning the rotary door handle, the panel power is terminated. If the disconnect is to
include fuse size provisions for the main motor starter, additional information is required.
The disconnect would have to be mounted external to the panel enclosure. The short circuit
capacity, maximum ground fault, motor full load amps, motor locked rotor amps and motor
voltage must be known to size the disconnect properly. Pricing varies depending upon the
size, amp rating of the fuse, which is required for protection.
NOTE
This option does not make fuse size provisions for the main motor starter.
