Specifications

Section 3: Installation Planning
3-17
3.8 ALTO 818 MOUNTING
The Alto 818 should be installed in an electrical equipment cabinet such as a NEMA Type I Panel
Enclosure or any other enclosure that is designed to house electrical and electronic controls that
do not require an oil- or dust-tight atmosphere. All devices should be mounted on nonconductive
surfaces, so devices are not grounded to the building when AC power is removed.
The SE 3708CU or the SE 3718SU power modules can be located in the same cabinet as the
Alto 818. Neither the SE 3708CU nor the SE 3718SU should be mounted below the ACU as the
heat generated by the power module can raise the ambient temperature of the ACU beyond its
maximum acceptable limit. Mount the SE 3708C or the SE 3718S vertically so that it receives
proper airflow around the heat sink.
If the temperature inside the enclosure is found to rise to 120° F (49° C) or more, cut ventilation
holes or slots in both the bottom and the top of the enclosure. If natural convection air current
is insufficient to prevent an ambient temperature of less than 120° F, a cooling fan must be used
to force cooling air through the enclosure.
To mount the Alto 818, observe the following restrictions:
 Wiring clearance is 6 inches (15 cm) around the edges of each unit.
 Service clearance is approximately 8 inches (20 cm) at the front of each unit.
 Adequate enclosure ventilation must be provided. Install a cooling fan if required.
 Anti-tamper switch is installed on enclosure door.