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Replacing a Telephone Jack

Electrical and Lighting, Interior, Ask Danny Published 03/06/2008 by Danny Lipford

Is it difficult to replace an existing telephone jack? Does the electricity need to be turned off to replace it? -Sylvia

Sylvia,

Replacing a phone jack in not difficult and typically just requires transferring the color coded wires from the old jack to the matching terminals on the new one. While telephone lines do have 48 volts of electricity running through them, it’s usually not enough to cause a shock, though it may affect a pacemaker.

The electricity in a phone line does spike to around 90 volts when the phone rings, which can give a mild shock. To prevent this from happening, unplug the modular jack at the telephone interface box where the line runs into your house, and check to be sure the phone is dead before working on it. Another option is to take a second phone off the hook to prevent it from ringing.

Since phone lines have their own source of electricity, they remain energized even when the power is off, so flipping the breakers to your house will not make any difference. Also, never work on the phone line during a thunderstorm since lightning can travel through the wire and result in serious injury.

For more information on replacing a phone jack, see our article How to Install a Phone Jack.