BECKHOFF EL1904 - Manual (Page 21)

Operation
EL1904 19
4.1.3 Mechanical installation
DANGER
Serious risk of injury!
Bring the bus system into a safe, de-energized state before starting installation,
disassembly or wiring of the Bus Terminals!
4.1.3.1 Control cabinet
The TwinSAFE terminals must be installed in a control cabinet or terminal box with IP54 protection class
according to IEC 60529 as a minimum.
4.1.3.2 Installation position and minimum distances
For the prescribed installation position the mounting rail is installed horizontally and the mating surfaces
of the EL/KL terminals point toward the front (see illustration below). The terminals are ventilated from
below, which enables optimum cooling of the electronics through convection. The direction indication
“down” corresponds to the direction of positive acceleration due to gravity.
In order to ensure optimum convection cooling, the distances to neighboring devices and to control
cabinet walls must not be smaller than those shown in the diagram.