Data Sheet for Product

Enclosure Ratings and Their Applications Technical Bulletin
Document Number 155-756
August 29, 2018
Siemens Industry, Inc. Page 3
IP Rating vs.
UL Type vs.
NEMA Type
Enclosures
(Continued)
NEMA Type enclosure ratings are written as application descriptions and generally
follow the same guidelines as UL Type. One significant difference between NEMA Type
and UL Type ratings is that NEMA does not require third-party testing and leaves
compliance completely up to the manufacture.
Applying the
Appropriate
Enclosure Rating to
the Application
UL Type 1 Enclosure
• Use in clean and dry mechanical rooms.
• Cover during the construction phase to ensure equipment does not get infiltrated
with construction dust.
• Use in environments that do not exceed 95% non-condensing humidity. This
requirement is usually exceeded when the mechanical room is a penthouse or
similar area that is directly open to the outside because most areas of the country
exceed these levels for at least parts of the year.
• SED2 NEMA Type 1 VFD, Conventional Bypass Option, and Electronic Bypass
Option packages all fall into the category.
UL Type 12 Enclosure
• Dusty locations.
• When the equipment must be operational during the installation phase.
• Air plenum mechanical rooms.
• Air stream mounting.
• Splashing water, in limited amounts, is possible. Such locations may include pump
rooms.
• Penthouse and similar areas that are open to the extreme temperature swings,
humidity changes and corrosive properties of the uncontrolled outside environment.
Ocean area penthouses in particular are good locations for NEMA 12 in that the
humid salt air is particularly electrically deductive and corrosive to electronic
products.
• SED2 IP54/UL Type 12 VFDs are appropriate for these locations. If a bypass is
required for a UL Type 12 drive, contact the VFD group at Siemens Industry, Inc.
UL Type 3R
• Outdoor locations that may be exposed to falling rain, snow and ice.
• Indoor locations that may be exposed to falling water. Such locations may be those
that have sprinkler fire protection.
• SED2 NEMA Type 3R Bypass packages are appropriate for these locations. See
SED2 VFD NEMA Type 3R Bypass submittal document (Document No. 154-062).