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Proprietary Information: Not for use or disclosure except by written agreement with Calix.
May, 2023.
b. Verify the type of mounting post for the earth ground and crimp the desired
termination hardware onto the opposite end of the wire.
Note: Grounding surfaces must be brought to a bright finish and coated with antioxidant
before being joined. When grounding to any surface, ensure that there is no paint or
debris between the ground lug and the rack frame. To ensure a reliable ground bond,
apply an anti-oxidant and use paint piercing star washers and thread forming screws to
secure a metal-to-metal ground contact to the u4hm enclosure.
Note: For PoE powered systems only: If you use an indoor PoE injector or PoE switch, you
must also use a PoE+ Ethernet surge protector (not supplied) on the Ethernet cable run
between the injector and the u4hm system located outdoors.
Grounding Considerations
The National Electric Code (NEC), the Rural Electric Association (REA), and state and local
codes require that this equipment (aka "the system") be properly grounded. The system must
be installed using the ground lug supplied with this enclosure to be compliant with UL
listings. A proper ground bonds the system to the building's primary earth electrode. The
bonding conductor used must be a #6 AWG copper or equivalent. The NEC grounding
requirement stipulates that earth electrodes must conduct to earth with no more than 25
ohms of resistance. If 25 ohms cannot be achieved with a single electrode, a secondary
electrode must be used and bonded together using a #6 AWG copper conductor or
equivalent.
The system must be installed to an auxiliary ground source to be compliant with UL listings.
The primary method of grounding in this application will be to bond the Main Electronics
Module (MEM) to the building's electrical ground circuit. The bonding conductor used must
be a #14 AWG copper or equivalent fastened to the MEM using a #10-32 pan head screw
with external tooth washer.
For installations requiring a bonding conductor of #6 AWG copper or equivalent, Calix
offers a Ground Lug Kit. This kit includes a ground lug, a #10-32 x 7/16-inch pan head
screw and external tooth washer.
Ground electrode requirements
The secondary ground electrode must be spaced at least 8 feet away from the primary
electrode. The primary and secondary electrodes, once bonded together, become the
building's primary ground point. Neither UL, NEC, nor REA require any additional
electrodes to be installed unless the system is located more than 20 feet away from the
building's earth electrode.
If the system cannot be installed within 20 feet of the building's primary earth electrode, an
additional ground electrode must be provided and bonded to the primary ground point of
the building. A #6 AWG copper conductor or equivalent bonding jumper must be used
between the earth electrodes and the system.
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