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1.5.4 Protectors, Bonding and Grounding
Protectors
The station protector is the last connection point for drop wire when you install a single line service.
Station protection provides a path to ground in case of excess voltage. It is important to install a
protector properly in order to protect the safety of telephone users and employees, as well as to
prevent damage to property.
Protection is designed to provide a path to ground if a voltage over the rating occurs as it will bleed off
excess current to ground. If the protection is not functioning correctly, the increased current flow may
cause the wires to overheat, which may be a fire hazard.
Protection is provided on the tip and the ring, both at the CO and at the customer's premise. Always
determine whether the existing protection and grounding is correctly done and sufficient to support any
additional services that you are installing.
BET / MIT grounding
BET and MIT grounding is normally done by the outside build (construction), so you will not normally
need to do this. But you will need to verify that the terminal is grounded if you are working with it. In
the event that you notice a missing ground, you will need to repair it only if trained and equipped to do
so. Otherwise, notify your manager.
All BETs and MITs need to be grounded from the ground lug on the terminal to the premise power
ground. The minimum gauge for this is a #6 AWG.
Older style business entrance terminals are also grounded with#6 AWG wire to a copper strap that runs
behind all the terminals into which the individual modules are attached.
BET bonding
When two BET’s are placed together they need to be bonded with a #6 AWG wire between the two.
TII 356
The Tii 356 is a fuse less protector; a NIB with a Tii 356 protector is the company standard. A fuse less
protector must be used if the customer has a power company multi-grounded neutral (MGN) or a known
grounded community metallic cold water supply.
The Tii 356 is the demarcation point between outside plant and inside wiring, and between Central office and
the customer. The test jack on the Tii 356 enables the customer to check their line themselves. Being able to
find out that the trouble is in their home can save them the expense of a service call.
The 356 module is entirely self-contained and consists of:
a Tii heavy duty three-electrode gas tube surge arrester
a fail short mechanism
Insulation displacement connections (IDC) for Telco and customer wiring
an RJ-11 jack as a demarcation
The Tii 356 must be used for all xDSL and TELUS TV installations.
For all new installs and repairs, the existing protector must be upgraded to the Tii 356.
Installing the Tii 356
The Tii 356 should be installed in a network interface box (NIB).
Do not strip the wire before inserting into IDCs.
Using the Mini Rocker tool, follow this connector termination procedure:
