Eaton Crouse-Hinds MTL5500 Series Instruction Manual page 23

5 .1 .5
The effect of corrosion on DX enclosures is negligible.
5 .1 .6
The flammable properties of the materials used in the construction of the enclosures are well
understood by manufacturers and ratings have been established to a number of standards. One of
the better known standards is the Underwriter's Laboratory standard UL 94 and the ratings for the
enclosure materials are given as:
Polycarbonate (all lids)
Polycarbonate with glass reinforcement (DX070 base)
Polyester with glass reinforcement (DX170 & DX430 bases)
Items made from similar materials are well established as suitable for use in process I/O marshalling
areas.
5 .1 .7
The enclosure designs have been tested to an impact resistance of greater than 2 Joules which
exceeds the BS EN 61010-1 requirements of 0.5 Joules.
5 .1 .8
The overall chemical resistance of the enclosures is limited by the resistance of the transparent
polycarbonate lid. The glass-reinforced polycarbonate/polyester (GRP) bases have a higher resistance
than plain polycarbonate. Table 5.5 lists qualitative evaluations of resistance to a variety of chemical
agents.
Table 5 .5: Qualitative evaluations of resistance to various chemical agents
Salt water; neutral salts; acids (low concentrations); hydraulic oil
Alcohols
Acids (high concentrations); alkalis (low concentrations); petrol; cooling fluids
Alkalis (high concentrations); solvents.
5 .2
5 .2 .1
These instructions are concerned solely with mounting the DX enclosures. Instructions for
wiring and testing individual modules within the enclosures are provided in Section 6.
Sufficient space is provided within the enclosures to accommodate tagging and earth-rail
accessories but this is at the expense of a reduction in the number of modules that can be
fitted.
5 .2 .2
5 .2 .2 .1
The DX enclosures are intended for safe (non-hazardous) area use.
The enclosures are rated NEMA 4X; consequently, in N. America or Canada, assuming the
modules have the required approvals, they can be used in Class 1, Division 2 (gases) location,
but check with local requirements and ensure all cable entries also conform. In this case, an
additional warning label will be required on or near the enclosure warning that the MTL5500
interfaces must not be removed unless the area is known to be non-hazardous. The enclosures
are NOT suitable for Class II or III, Division 2 hazardous locations.
15
Corrosion resistance
Flammability rating
Materials
Impact resistance
Chemical resistance
Chemical agents
Mounting
General
Location and orientation
Location
UL94 rating
V2/V0
V1/V0
V0
Qualitative
evaluation
of resistance
Excellent
Very good
Good
Poor
INM 5500 Rev 11