Honeywell STT850 Quick Start Manual page 7

A.5 Conditions of Use" for Ex Equipment", Hazardous Location Equipment or
"Schedule of Limitations":
Consult the manufacturer for dimensional information on the flameproof joints for
repair.
Painted surface of the STT850 may store electrostatic charge and become a source
of ignition in applications with a low relative humidity less than approximately30%
relative humidity where the painted surface is relatively free of surface
contamination such as dirt, dust or oil. Cleaning of the painted surface should only
be done with a damp cloth.
Intrinsically Safe: Must be installed per drawing 50091227
Division 2: This equipment is suitable for use in a Class I, Division 2, Groups A, B, C,
D; T4 or Non-Hazardous Locations Only.
The installer shall provide transient over-voltage protection external to the
equipment such that the voltage at the supply terminal of the equipment does not
exceed 140% of the voltage rating of the equipment.
The enclosure is manufactured from low copper aluminium alloy. In rare cases,
ignition sources due to impact and friction sparks could occur. This shall be
considered during Installation, particularly if equipment is installed a Zone 0
location.
If a charge-generating mechanism is present, the exposed metallic part on the
enclosure is capable of storing a level of electrostatic that could become incendive
for IIC gases. Therefore, the user/ installer shall implement precautions to prevent
the buildup of electrostatic charge, e.g. earthing the metallic part. This is
particularly important if equipment is installed a Zone 0 location.
A.6 Control Drawing
STT850/750 Quick Start Guide 7