331 / 356
D-83
D
T P
S K
×
---------
=
Additional informations
Quick calculation charts
for internal temperatures
For the enclosures not mentioned on the previous
pages, use the equation:
where:
D
T
: internal temperature - external temperature
P:
power dissipated by the devices, connections and
busbars (in Watts)
S:
total free surface area of the enclosure
(expressed in m
2
)
K:
thermal-conduction coefficient of the material
(W/m
2
°C)
Note:
the dissipated power of each device is provided by the
manufacturer. Add approximately 30 % to account for the
connections and the busbars.
Test conditions: the cubicle is on the floor against a wall, the indicated internal heat
rise is that measured at mid-height in the enclosure.
IP3X cubicle, 400 mm deep
IP3X cubicle, 600 mm deep
DD382424
DD382425
IP3X cubicle, 800 mm deep
IP3X cubicle, 1000 mm deep
DD382426
DD382427
IP55 cubicle, 400 mm deep
IP55 cubicle, 600 mm deep
DD382428
DD382429
IP55 cubicle, 800 mm deep
IP55 cubicle, 1000 mm deep
DD382430
DD382431
K = 5.5 W/m2 °C for painted sheet metal.
Thermal management
of switchboards
Charts
Thermal characteristics of
switchboards