Page:Incandescent electric lighting- A practical description of the Edison system.djvu/81

 with the sockets by the screws shown in the cut, while the branch wires are led off from the screws shown between the sockets on either side of the cut-out. Similar cut-outs, with three sockets on each side, are provided for three wire branches.

In the two wire cut-outs the buttons of two of the sockets are connected to the central or neutral wire, while the buttons of the two other sockets are connected with the positive and negative wires respectively, thus disposing the lamps on the branches equally on both sides of the system. In the three wire cut-outs, two of the sockets connect with each of the three main wires.

These cut-outs are called two-branch cut-outs as they admit of a branch circuit being led off from both sides of the main circuit. Out-outs similar to these are provided to meet all the requirements of distribution for interior lighting.

Switches, like cut-outs, vary in form according to the purpose for which they