How to use a terminal block

Updated February 21, 2017

A terminal block is designed to receive and connect wires in a central location. A commonly used terminal block type is found in household appliances like stoves and dryers. The terminal blocks, or wiring blocks, in major appliances align the hot, neutral and ground connectors needed for attaching a power cord. Other terminal block applications are found in electric breaker panels, electronic circuitry and 12-volt automotive and marine systems. Automotive, electronic and electrical terminal block wiring is designed for making connections easily.

Attach a power cord to the electrical terminal block in a major appliance. Remove the screw terminals on appliance terminal block applications with a slotted screwdriver. Place the connector spades or rings from the appropriate coloured power cord wires onto the terminals. Connect the red and black wires to the outer terminals on the row of three. Connect the white wire to the centre terminal and connect the green wire to the ground terminal on the body below the centre terminal. Tighten all screw terminals firmly.

Connect electrical wiring to an electrical terminal block in a breaker panel. Breaker panel blocks are the strips of screw terminals on the ground bus bar and neutral bus bar. Ground wires in household electrical cables are bare copper wires. Strip 1/2 inch of the white insulation from 12- or 14-gauge neutral wires with wire cutters. Loosen a terminal screw with a slotted screwdriver on the ground bus bar holding the bare copper and green insulated wires, or on the neutral bus bar with all the white wires. Insert the bare or stripped wire end into a slot on the appropriate block and tighten the screw firmly.

Attach various electronic terminal block applications to circuit boards. Clip or slide electronic terminal block types onto DIN rails. Solder PCB terminal blocks to printed circuit boards with a soldering iron. Push unstripped wires into insulation displacement terminal clamps on terminal block types with such connectors. Strip other small gauge electronic wiring with wire strippers. Connect the wires by opening spring terminal clamps with a pen and inserting them into the tension clamps, or by pushing them into clamps secured by screw terminals and tightening the screws with a small Phillips screwdriver.

Plug fuses into a 12-volt terminal block or fuse block to protect automotive and marine circuits from surges. A 12-volt terminal block type has small slot sockets for receiving mini fuses. Connect the hot wire from a 12-volt appliance to the terminal block for a fuse that carries an appropriate amp load and plug a mini fuse with that amp rating into the socket.


Electrical wiring of any type must be properly executed to avoid damage to circuits and appliances, and also to prevent bodily injury. Installations on electrical, electronic and 12-volt applications require training and experience. Do not experiment with terminal block wiring.

Things You'll Need

  • Wire cutters
  • Slotted screwdriver
  • Wire strippers, small gauge
  • Pen
  • Soldering iron
  • Solder
  • Small Phillips screwdriver
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About the Author

Jonra Springs began writing in 1989. He writes fiction for children and adults and draws on experiences in education, insurance, construction, aviation mechanics and entertainment to create content for various websites. Springs studied liberal arts and computer science at the College of Charleston and Trident Technical College.