Transition Networks SM8TAT2SA-DC Install Manual page 21

Transition Networks SM8TAT2SA-DC Install Guide
ATTENTION: This SM8TAT2SA-DC case must be earth grounded for correct operation of internal transient
protection circuitry.
Neither DC input polarity may be earth grounded. If DC power distribution bus has one side tied to earth ground,
then the use of an isolated DC-DC power Supply between the DC power distribution bus and SM8TAT2SA-DC is
required to ensure that the PoE ports are isolated from earth ground as required by IEEE802.3af/at/bt
specification.
If it is not possible to use an isolated DC-DC power supply then all interconnected devices must be bonded to a
common earth ground with all connection points within the same building.
See "PoE Deployment Environments A and B" on page 22.
Caution: The switch is an indoor device. If it is to be used with outdoor devices such as outdoor IP cameras or
outdoor Wi-Fi APs, then you are strongly suggested to install a surge protector or surge suppressor in order to
protect the switch.
Compliant with 802.3at in Environment A when using an isolated power supply. For 802.3at Environment B
applications, i.e. building to building, copper to copper endpoint connections: 1) use an Ethernet network
isolator module (PoE disabled), or 2) use mid-span injector (s), e.g. MIL-L100i, L1000i-at, between this switch's
PSE port and link partner PD port.
33814 Rev. A https://www.transition.com Page 21 of 43