AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |
Back to Blog
3 wire 240 volt plug1/22/2024 ![]() Since a neutral should never be switched, assume that any white wire that you find connected to a switch is a hot wire until you test it and determine that it isn’t. That wasn’t always done, so be careful of white wires in switch boxes. In those cases, the white wire should be marked with red or black electrical tape or permanent marker-or any color other than gray or green-to show that it is being used as a hot wire and is carrying ungrounded potential. Because that requirement was only adopted in 2011, though, a homeowner may find that one has been used that way in an existing installation. In new work, the white wire in a cable assembly cannot be used to carry ungrounded power. ![]() This changed with the adoption of the 2011 cycle of the NEC, which requires the presence of a grounded conductor in every switch box, to facilitate the installation of lighted switches, motion detectors, timers, and similar energy-saving controls. In the past, a white wire in a cable assembly was allowed to be used to carry ungrounded potential-to function as a hot wire-in a switch leg or when connecting a set of 3-way switches. For conductors as small as those found in residential branch circuits, only a white or gray wire may be used for that purpose. White WiresĪ white wire is typically used as the neutral wire or grounded conductor. ![]() That makes it easier to tell, at a glance, which switch is being used to control each set of lights. For example, if power needs to be run from a ceiling box down to a box with three switches and then brought back to the ceiling to power three different sets of lights, a black wire could be used to take the power down to the switches and three wires with other colors-say red, blue, and yellow-could be used to bring the power up from each of the switches. In systems where individual conductors, or wires, are run through a conduit, wires that are blue or yellow, or any color except white, gray or green are sometimes installed to designate a specific use. The red wire is also used as a by-pass in a two-way switched lighting circuit, and will often be used also as an interconnection or communication wire in a circuit that requires it, such as a smoke detector circuit. No wire with any of those colors can be used for establishing a ground or neutral connection.īecause a red-colored wire also serves as an ungrounded conductor, these wires are used to connect the second leg of the electrical system to loads which require 240 volts. In fact, any color wire except white, gray or green may be used in conduit to carry ungrounded power. Black and Red WiresĪccording to NEC, a black or red wire must be used as an ungrounded conductor or hot wire. The colored marks correspond to the colors of the current-carrying conductors in that cable. In recent years, manufacturers have begun spraying color codes onto cables with metal sheathing. Type MC cable does have a grounding conductor. The metal sheath, plus a thin aluminum bonding wire, provide the required path to ground. Type AC cable, commonly called BX, does not have a grounding conductor. Both Type MC and Type AC are sheathed in a flexible metal coil. The other two types of cable, which are often used to extend wiring in a system wired with metal conduit, are Type MC (Metal Clad) and Type AC (Armor Clad). “14-2/G”, for example, shows that that cable has two insulated, current-carrying conductors and one grounding conductor, size 14 AWG. Type NM cable will also have markings on the cable sheath of the cable, indicating the size and type of the conductors in it, along with other information. Modern Type NM cables have different color sheathing which indicates the size of the conductors: White for 14AWG (American Wire Gauge) conductors, Yellow for 12 AWG conductors, and Orange for 10 AWG conductors. Plastic sheathed, or Type NM (NonMetallic), cable, is widely used for home wiring circuits. A cable is a factory-made assembly of conductors in an outer jacket or sheath. Wiring Typesĭepending on where you live, the branch circuit wiring in your home will be made with individual conductors run through a hollow metal conduit, or with one of three types of cable. In the United States, the color of the wire used must comply with the requirements of the National Electrical Code (NEC).Ī Word of Caution: Always use a line voltage meter or circuit tester to determine if a wire is "hot" or "live." Never rely on a wire's color alone. The connections should not be made haphazardly. Understanding the information those colors convey helps you work with greater safety and ease when troubleshooting an electrical problem or making repairs or improvements to your electrical system.
0 Comments
Read More
Leave a Reply. |