Rockwell Automation 2705 REDIPANEL KEYPAD MODULE USER MANUAL - Manual (Page 13)

Chapter 3
Installing the Bulletin 2705 Keypad Module
3–2
Grounding is an important safety measure in electrical installations. With
solid state systems, as we mentioned before, grounding also helps to limit the
effect of noise due to EMI (electromagnetic interference).
An authoritative source on grounding requirements is the National Electrical
Code published by the National Fire Protection Association of Boston,
Massachusetts. An article of the Code discusses the types and sizes of wire
conductors and safe methods of grounding electrical equipment and
components.
You must use a NEMA enclosure to protect the electronics of the Keypad
Module from atmospheric contamination. Standards established by the
National Electrical Manufacturer’s Association (NEMA) define enclosure
types based on the degree of protection an enclosure will provide.
Select an enclosure that meets the requirements of NEMA Type 4.
Within the NEMA enclosure, the Keypad Module (or modules) needs enough
room to allow for convection cooling. If the ambient temperature around the
enclosure is below +40
°
C, you may use an unvented enclosure.
To mount several modules in the same enclosure, follow these guidelines
(see Figure 3.1 on the following page):
•
Vertical stacking of modules: The lower edge of the top cutout must be
at least 6 inches (15cm) from the top edge of the lower cutout. The
enclosure must be at least 8 inches (20cm) deep.
•
Horizontal mounting: You can mount modules as close together as
physically possible. The enclosure must be at least 8 inches (20cm) deep.
In some applications, you may also have to deal with heat produced by other
equipment inside (or outside) the enclosure. In such a case, you may place
blower fans inside the enclosure to assist in circulating air to reduce hot spots
near the components.
Do not bring in unfiltered outside air - it could contain contaminants or dirt
harmful to the components.
In extreme cases, you may have to use air conditioning to protect against heat
buildup within the enclosure.
Grounding
NEMA Enclosures