Depot areas tend to have only a single wire and are known as simple equipment.

As in many things, no single wire is perfect for all applications.

There will have to be a single wire to each individual claim.

Along the ceiling ran a single wire from which a light bulb hung every few yards.

The contribution of a single wire may be determined with reference to Fig. 4.5.

Unless you can spot all the poles, single wires will be very difficult to see.

The ideal warning light must be able to power itself while clamped to a single wire of the line.

Typically a single wire is used, with the return current running through the track.

This can be a single wire with an on/off signal.

Many of these were, and maybe still are, wired with a single wire and common earth return.