How to Install Phone Junction Box

Updated July 20, 2017

Connecting a terminal block in a central location is an easy way to expand your telephone wiring as the need arises. Only one pair of wire is needed for single line telephones. It is always a good idea to wire in a second pair in case a second phone line is ever needed. It can also be used if the first pair of cable ever gets damaged. Most new installations use four pairs of Category 5 cable. This cable is very versatile and can handle both voice and data applications.

Examine the wires that are to be connected to the terminal block to find the colour coding scheme. The most common colour codes for 2-pair cable are green, red, yellow and black. Colour coding for the newer Category 3 and 5 types are white/blue, white/orange, white/green, and white/brown. Notice Tate each of the white wires have a corresponding colour tracer mark on them.

Obtain a 4-lug telephone terminal block for 2-pair cabling and an 8-lug terminal block for 4-pair cable.

Find a central location to mount the terminal block. Locate it where you can connect all the wiring to it.

Remove the cover from the block. Attach it to a secure base using the screws provided. Trim each of the wires so there is about three inches left to connect to the block.

Remove about two inches of the outer insulation from each of the cables with a utility knife. Separate the wires into pairs. The 2-pair cable will be green and red for the first pair and yellow and black for the second. The 4-pair colour code is white/blue for the first pair, white/orange for the second, white green for the third, and white/brown for the fourth.

Remove about 1/2 inch of the insulation from cable pairs with a set of wire strippers. Loosen all of the screws inside the terminal block and wrap the bare wire between the washers using needle nose pliers. Match the colours of each wire to the same terminal lug.

Connect the green and white wire together with a blue tracer, the red, blue, black and white with a green tracer, and yellow with the green together when mixing different types of cable to the same block.

Reattach the cover over the block. Test the jacks by plugging in a telephone set at each location, picking up the receiver and listening for a dial tone.

Things You'll Need

  • Phone terminal block
  • Utility knife
  • Wire strippers
  • Needle nose pliers
  • Screwdriver
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