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In accordance with 250.94, an intersystem bonding termination for connecting a minimum of three intersystem bonding conductors required for other systems shall be provided external to enclosures at the service equipment or metering equipment enclosure.

Exception: In existing buildings, if any of the intersystem bonding and grounding electrode conductors required by 800.100(B)(2) exist, installation of the intersystem bonding termination is not required. An accessible means external to enclosures for connecting intersystem bonding and grounding electrode conductors shall be permitted at the service equipment by at least one of the following means:

1) Exposed nonflexible metallic raceways

2) An exposed grounding electrode conductor

3) Approved means for the external connection of a copper or other corrosion-resistant bonding or grounding electrode conductor to the grounded raceway or equipment

As noted in 800.100(B)(2), "A bonding device intended to provide a termination point for the grounding electrode conductor (intersystem bonding) shall not interfere with the opening of an equipment enclosure. A bonding device shall be mounted on non-removable parts. A bonding device shall not be mounted on a door or cover even if the door or cover is non-removable."

The telephone system bonding/grounding wire attached to the cover screw at the top of the meter enclosure definitely interferes with the opening of the cover. The phone system would lose its ground/bond connection every time the meter enclosure cover needed to be removed for maintenance or servicing of the electrical system. This could result in a difference of potential between the two systems and could result in a shock or fire hazard.

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