96
Low Voltage Switch Gear
Appendix
■
Technical information
Degree of protection acc. to EN60947
Protection ratings are prefixed by the internationally agreed letters IP
followed by two digits.
1
st
digit:
Pertains to solid objects
2
nd
digit: Pertains to water.
Terminal markings acc. to EN50011
Auxiliary contacts of AC contactors and contacts of contactor relays
and thermal overload relays are particularly marked. The terminal
markings of normally-open contacts are printed as positive figures,
they of normally-closed contacts as negative figures.
This gives a clear indication of the function of the contacts.
The figure below illustrates the determination of terminal markings
for contactors with auxiliary contact blocks.
Resistance to climatic conditions acc. to IEC 68
Open-type devices are climate-resistant in the constant climate
according to IEC 68-2-3 (this is a climate with an ambient tempera-
ture of 40°C and an atmospheric humidity of 90 to 95%).
Enclosed devices are climate-resistant in an alternating climate
according to IEC 68-2-30 (this is a moist alternating climate with a
24-hour cycle between climates with an ambient temperature of
25°C, and an atmospheric humidity of 95 to 100% and an ambient
temperature of 40°C, and an atmospheric humidity of 90 to 96% in
the presence of condensation during rises in temperature).
Data are valid up to an altitude of 2000m above sea level.
Short circuit protection
Back up fuses should be used to protect contactors and starters
against short circuits. For starters the device with the smaller admis-
sible fuse at the main and at the control circuit (contactor or thermal
overload) determines the fuse size.
After a short circuit devices have to be checked for correct operation.
Disconnect power before proceeding with any work on the equipment!
1
st
digit
Short description
Definition
1
Protected against
solid objects great-
er than 50 mm
Excludes solid objects exceeding
50 mm in diameter and protects against
contact with live and moving parts by a
large body surface such as a hand (but
not against deliberate access).
2L
Protected against
solid objects great-
er than 12,5 mm
and against contact
by standard test
finger
Excludes solid objects exceeding
12,5 mm in diameter and protects
against contact with live and moving
parts by a standard test finger or similar
objects not exceeding 80 mm in length.
3
Protected against
solid objects great-
er than 2,5 mm
Excludes solid objects exceeding
2,5 mm in diameter or thickness.
4
Protected against
solid objects great-
er than 1 mm
Excludes solid objects exceeding 1 mm
in diameter or thickness.
5
Dust protected
Prevents ingress of dust in quantities
and locations that would interfere with
the intended operation of the equip-
ment.
6
Dust tight
Prevents ingress of dust.
2
nd
digit
Short description
Definition
1
Protected against-
dripping water
Dripping water (vertically falling drops)
shall have no harmful effect.
2
Protected against
dripping water
when tilted up to
15°
Vertically dripping water shall have no
harmful effect when the enclosure is tilt-
ed at any angle up to 15° from its nor-
mal position.
3
Protected against
spraying water
Water falling as a spray at an angle up
to 60° from the vertical shall have no
harmful effect.
4
Protected against
splashing water
Water splashed against the enclosure
from any direction shall have no harm-
ful effect.
5
Protected against
water jets
Water protected by a nozzle against the
enclosure from any direction shall have
no harmful effect.
6
Protected against
heavy seas
Water from heavy seas or water pro-
jected in powerful jets shall not enter
the enclosure in harmful quanties.
7
Protected against
the effects of im-
mersion
Ingress of water in a harmful quantity
shall not be possible when the enclo-
sure is immersed in water under stan-
dard conditions of pressure and time.
8
Protected against
submersion
No ingress of water.
The complete terminal marking according
to EN 50011 and EN 50012 results from the
sequence numbers on the contactor relay
or ac contactor (2., 3.) and the function
numbers on the auxiliary contact blocks
(e. g. .1, .2, or .3, .4).
Sequence number
Function number
