DIY Frequently Asked Questions / Thermostat Cable')">
Used in low-voltage control, alarm and communication systems. Most common types are braided, twisted and plastic-jacketed types. All three use solid copper conductors and are twisted and insulated with plastic.
Although thermostat cable is low voltage, it carries an UL-listing for being flame-retardant, since it is installed in the wall. Wiring used in security alarm and smoke detection systems must be UL-listed.
Twisted cable, which has no outer braid, is used in doorbells, burglar alarms, intercom telephones and public address systems.
Braided cable is covered with cotton braid and is used primarily in thermostat controls and other low-voltage, remote control circuits.
Plastic-jacketed cable is also used in similar low-voltage applications.