A shielded wire is a wire which has been covered with protective sheathing to reduce the amount of electromagnetic radiation which it emits. This is designed to reduce the amount of electromagnetic interference (EMI) associated with that wire. There are numerous types of shielded wire available which can be used in many different applications. Hardware and electronics stores usually carry this product, and can order specialty products by request from their customers if someone needs a particular type, brand, design, or style for a project.
Many people are at least passingly familiar with electromagnetic interference. Some examples include distortions on monitors and televisions caused by EMI, crosstalk on mobile phones and cordless telephones, interruptions in radio playback, and flickering of electric lights. Electromagnetic interference can be caused by nature, or by various devices in the vicinity, especially if wires cross close to each other. It can damage a circuit or interfere with its operation, and it is often extremely irritating.
With shielded wire, even when wires run near each other, they cannot interfere with each other. People can use shielded wire wherever wiring is likely to overlap, and shielded conduit for things like household wiring. People opt to use shielding if they suspect that a particular device might cause electromagnetic interference. For example, a big television could be fitted with a shielded wire as a power cord so that it will not cause problems with other devices in the area.
Companies which design shielded wiring and shielding kits generally test their products thoroughly to confirm that they will work. The wire may indicate the tolerances it has been tested for so that people know if it is appropriate for the setting or not. It is important to select a product which will provide adequate shielding or interference can continue to be a problem despite the use of shielding. People who are not sure about what kind of wiring to get can ask a contractor or electrician for advice.
Many different types of wiring are made available in shielded form for convenience. People can also add shielding to existing wiring with various wire shielding kits which are often available through electronics stores and the electrical department at places like home improvement stores. As a general rule, it tends to be more expensive to install shielded wiring, but the wiring may be necessary or strongly recommended to keep devices functioning properly, in which case people may view the expense as acceptable, given the conditions.