Phone Line Customer Service Box

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That is correct and has been required by code for many years.
Specifically, telco and CATV services must be bonded to the MGN (Multi-Grounded Neutral) wire of the premise using the SHORTEST length of wire as is practical.
This provides the best "balanced potential" in grounding. It is said that such practice lowers the chance that, in a direct lightening strike, the charge will "leap" from a phone or CATV jack to an electrical outlet. I have seen that sort of damage. It's impressive.

For the BEST service and the best protection from transient spikes (surges), you WANT the SNI/D at the electric service entrance.
For the first, hundred years or so, telephone service was brought into a premise at virtually ANY location. They often used a ground rod (4-ft galvanized!) instead of a water pipe for bonding.
The proliferation of electronic devices (MUCH more susceptible to surge damage than the old phones) connected to the network made common bonding imperative.
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JR

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Jim Redelfs wrote:

The NEC requires a wire "short as practical" with a max length of 20 ft from phone/cable entry protectors to the power grounding-electrode-system. (For 1 and 2 family dwellings, if the wire has to be over 20 ft it can be longer with a ground rod near the entry protector.) For phones, even 20 ft can be too long.
Phone people like Jim are likely well aware of this. Cable people, particularly contractors, are more of a problem. .

Cant imagine.
With a lot of electronic equipment connected to both power and phone/cable, you want to minimize the voltage between power and phone/cable wires. Insurance information suggests the most common damage to electronic equipment is from high voltages between power and phone/cable wires. Having a *short* wire from phone/cable entry protectors to the ground at the power service minimizes the voltage between power and phone/cable wires. The power service is the magic point because neutral and ground are bonded at that point.
With a strong surge current to earth the "ground" at the building can rise thousands of volts above 'absolute' ground. You want the power and phone and cable grounds to rise together.
Art writes about high voltage between power and signal wires. There is an illustration of a cable ground wire that is too long starting pdf page 40 in an excellent IEEE guide on surges: <http://www.mikeholt.com/files/PDF/LightningGuide_FINALpublishedversion_May051.pdf
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