Residential House Wiring

N.E.C code

The National Electrical Code (NEC) specifies acceptable wiring methods and materials in the United States. Local jurisdictions usually adopt the NEC or another published code and then distribute documents describing how local codes vary from the published codes. They cannot distribute the NEC itself for copyright reasons. The stated purpose of the NEC is to protect persons and property from hazards arising from the use of electricity. The NEC is not any jurisdiction's electrical code per se; rather, it is an influential work of standards that local legislators (e.g., city council members, state legislators, etc. as appropriate) tend to use as a guide when enacting local electrical codes. The NFPA states that excerpts quoted from the National Electrical Code must have a disclaimer indicating that the excerpt is not the complete and authoritative position of the NFPA and that the original NEC document must be consulted as the definitive reference.

New construction, additions or major modifications must follow the relevant code for that jurisdiction, which is not necessarily the latest version of the NEC. Regulations in each jurisdiction will indicate when a change to an existing installation is so great that it must then be rebuilt to comply with the current electrical code. Generally existing installations are not required to be changed to meet new codes.

Enforcement of code requirements varies by jurisdiction in the United States. In many areas, a homeowner, for example, can perform household wiring for a building which the owner occupies; this may even be complete wiring of a home. A few cities have more restrictive rules and require electrical installations to be done by licensed electricians. The work will be inspected by a designated authority at several stages before permission is obtained to energize the wiring from the local utility; the inspector may be an employee of the state or city, or an employee of an electrical supply utility.

3 way switching

3-ways are used any time that you want two switches to operate one light (or lights).  The best example of this would be at either end of a long hallway, or at the top and bottom of a stairwell.

At a glance, 3-way switches look the same as the common single pole switch, but instead of having only two screws on which to make your connections, they have two connections on one side, and one on the other.

One of the three terminals is “identified” (by using a different color) and is usually the bottom screw on the side with two screws.  It is referred to as the “common” terminal, and the other two are known as “travellers”.  This is because the electrical connection either goes from the common screw, to one or the other travellers, depending on the switch position.

How to Wire a Basic 3-Way Switch:

There are several ways to wire up a 3-way circuit, and it would be very difficult to cover them all. 

Basic House Wiring

Now, let's take a look at the basic-house-wiring-diagram for low voltage wiring which is used mainly in doorbells, residential ...