Basic HTML Version
9/17
equipment enclosures according
to NEMA and UL
Environment and protection
Classification
1 2 3 3R 3S 4 4X 5 6 6P 12 12K 13
Indoor use
● ● ● ● ● ● ● ● ● ● ● ● ●
Outdoor use
● ● ● ● ●
● ●
Incidental contact with the equipment
● ● ● ● ● ● ● ● ● ● ● ● ●
Dirt
● ● ● ● ● ● ● ● ● ● ● ● ●
Drips and gentle splashes of non-corrosive liquids
● ● ● ● ● ● ● ● ● ● ● ●
Rain, frost(*) and snow
● ● ● ● ●
● ●
Frost (**)
●
Dust, fibres and particles in suspension
●
● ● ●
● ● ● ● ●
Built-up dust, fibres and particles in suspension
●
● ● ● ● ● ● ● ● ●
Clouds of dust
●
● ● ●
● ●
Splashes and jets of water
● ●
● ●
Gentle splashes and leaks of oil or non-corrosive coolants
● ● ●
Drips, splashing and spraying of oil or non-corrosive coolants
●
Corrosive agents
●
●
Occasional temporary immersion
● ●
Occasional prolonged immersion
●
(*) The operation of the external mechanisms is not required when the enclosure is covered with frost.
(**) The operation of the external mechanisms is required when the enclosure is covered with frost.
Enclosures
Type of protection (1)
1 2 3 3R 3S 4 4X 5 6 6P 12 12K 13
Steel wall-mounting enclosures
S3D
● ● ●
(*)
●
(*)
●
(*)
●
(*)
●
(**)
●
(**)
●
(**)
CRN
● ●
(*)
●
(*)
●
(*)
●
(*)
●
(*)
●
●
Stainless-steel wall-mounting
enclosures
S3X
● ●
(*)
●
(*)
●
(*)
●
(*)
●
(*)
●
(*)
● ●
(**)
●
(*)
Steel floor-standing enclosures
SM
● ●
(*)
●
(*)
●
(*)
●
(*)
●
(*)
● ● ●
(*)
Steel suitable enclosures
SF
●
● ●
Stainless-steel floor-standing
enclosures
SMX
● ●
(*)
●
(*)
●
(*)
●
(*)
●
(*)
●
(*)
● ● ●
(*)
Stainless-steel suitable enclosures
SFX
●
● ●
Thermoplastic boxes
TBS/TBP
●
●
● ● ●
Polyester modular boxes
PLS
● ● ● ● ● ● ●
●
●
Polyester wall-mounting enclosures
PLM
● ● ● ● ● ● ●
●
●
Polyester floor-standing enclosures
PLA
● ● ●
(*)
●
(*)
●
(*)
●
(*)
●
(*)
●
●
(*) 1 door.
(**) 2 doors.
Components
Type of protection (1)
1 2 3 3R 3S 4 4X 5 6 6P 12 12K 13
Ventilation system
CV
● ●
Thermal regulation system
CC
● ●
NEMA and UL are standardisation bodies, commonly recognised in North America,
which have issued classifications of enclosures according to the protection offered
in various environments.
These classifications are similar.
The 1st table below summarises this classification, which does not include
potentially explosive areas. The detailed recommendations of this classification are
given on the next page.
The 2nd table indicates the classification of our enclosures.
These classifications appear in our UL certifications (see Certification technical
annex on page
9/2
).
Certification according to the UL classification guarantees the corresponding NEMA
classification by equivalence.
(1) In some ranges the classification depends on the model and version. The detailed protection types are indicated in the UL certifications.
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