common wire

American  

[kom-uhn wahy^uhr] / ˈkɒm ən ˌwaɪər /

noun

Electricity.

1. a separate or extra wire serving to supply a smart thermostat with continuous power from a heating or cooling system, without interfering with the signals that alert the system to turn the heating or cooling on or off.

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Etymology

Origin of common wire

First recorded in 1870–75

Example Sentences

The most common wire gauges used in U.S. residential buildings are 14, 12 and 10.

From Seattle Times

This bottle was a mere ordinary bottle, with a common cork in its neck, into which a common wire had been inserted.

From Project Gutenberg

Ignoring at first the pilot relay and the pilot lamp, it will be seen that each of the tip-spring anvils of the jacks is connected to a common wire 1 which is grounded.

From Project Gutenberg

Each of the sleeve-contact anvils is connected through the coil of the line relay to another common wire 2, which connects with the live side of the common battery.

From Project Gutenberg

The showing of a separate ground for each of the line-relay armatures does not mean that literally each one of these armatures is connected by a separate wire to earth, and it is to be understood that the three separate grounds shown in connection with these relay armatures is meant to indicate just such a set of affairs as is shown in connection with the tip-spring anvils of the jacks, all of which are connected to a common wire which, in turn, is grounded.

From Project Gutenberg