316 / 338
D-82
Additional information
Thermal characteristics of
switchboards
Quick calculation charts for internal
temperatures
For the enclosures not mentioned on the previous
pages, use the equation:
P
S x K
D
T =
where:
DT:
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 m²)
K:
thermal-conduction coefficient of the material
(W/m² °C)
K = 5.5 W/m² °C for painted sheet metal.
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.eps
DD382425.eps
IP3X cubicle, 800 mm deep
IP3X cubicle, 1000 mm deep
DD382426.eps
DD382427.eps
IP55 cubicle, 400 mm deep
IP55 cubicle, 600 mm deep
DD382428.eps
DD382429.eps
IP55 cubicle, 800 mm deep
IP55 cubicle, 1000 mm deep
DD382430.eps
DD382431.eps
Thermal management of
switchboards
Charts