Connecting Electrical Wire/Cables and Connectors

Connection of wires is performed, in the majority, by two methods either by the use of plugs which insert in to a mating plug with a special external barrel with a screw thread which is turned to lock the connecting plugs together or by a form of terminal block. When using terminal blocks it is important to know the proper installation practice to prevent corrosion and damage to the block and terminals.

If you are connecting copper wire terminals to the block then you should

  • Connect the wire terminal directly onto the nut securing the terminal block stud.
  • Place a plain washer over the terminal.
  • Followed by a self locking nut or, if there is not a self locking nut available, you may use a spring steel locking washer followed by a standard nut.

If the terminal you are connecting is for an aluminium wire then you should

  • Place a plain brass washer over the terminal block stud securing nut
  • Then place the wire terminal onto the stud.
  • Followed by another plain brass washer
  • Then either a self locking nut or spring steel lock washer followed by a plain nut.

If you must connect an aluminium wire terminal and copper wire terminal to the same stud then the following order must be achieved:-

  • Place the plain brass washer onto the terminal stud followed by the aluminium wire terminal.
  • Place another brass washer over the aluminium wire terminal followed by the copper wire terminal
  • Then place a plain washer followed either by a self locking nut or a spring steel lockwasher and plain nut.

Please note that unless the wire terminals are of different materials i.e. copper wire terminals and aluminium wire terminals, then no washer should ever be placed between them.