Contemporary Control Systems BAScontrol20 Installation Guide - Manual (Page 5)

TD100700-0IA
5
Powering
The unit requires a source of 24 VDC or VAC via a two-pin removable
keyed connector.
NOTE:
This device is intended for use with Class 2 circuits.
The recommended size for power conductors is 16–18 AWG (solid or
stranded). Ground is directly connected to zero volts. Input connections
are reverse-polarity protected.
Limited Power Sources
The BASC20 should be powered by a limited power source complying
with the requirements of the National Electric Code (NEC) article 725 or
other international codes meeting the same intent of limiting the amount
of power delivered by the source. Under NEC article 725, a Class 2
circuit is that portion of the wiring system between the load side of a
Class 2 power source and the connected equipment. For AC or DC
voltages up to 30 volts, the power rating of a Class 2 power source is
limited to 100 VA. The transformer or power supply complying with the
Class 2 rating must carry a corresponding listing from a regulatory
agency such as Underwriters Laboratories (UL).
Indicator Lights
Power: If applied power is adequate, this LED glows solid green.
Ethernet: This LED glows if a valid link exists to an operating Ethernet
device. It flashes to indicate activity.
I/O: Each of these LEDs glows green when the associated I/O point is in
an active condition.