HEIDENHAIN TNC 410 M Technical Manual page 236

4 – 28
Danger
Mount the PW 21x braking resistor in a way that prevents the ingress of
splashing water (coolant). At the same time, a cover must be mounted to
make personal contact with the braking resistor impossible.
HEIDENHAIN Technical Manual for Inverter Systems and Motors
Leave space for air
circulation!
Temperatures of > 150 °C
are possible; Do not mount
any temperature-sensitive