Where must neutral and ground conductors be split into separate bus bars

Where must neutral and ground conductors be split into separate bus bars

I know that the electrical code requires that the ground and neutral be separate in the electrical panel and that the electrical panel has its own ground wire. However, I don't understand why, don't all grounds and neutrals terminate in the same place?

Different wires, different tasks.

Different wires, different tasks. As of the 2008 National Electrical Code, residential subdistribution panels must have a four-wire feeder (two active, neutral and ground) and the ground and neutral must be separate.

The ground and neutral must be separated from each other. In this case, they are connected to different buses in the distribution system.

Cliff Popejoy, a licensed electrician in Sacramento, California, responds, "First, let's look at the role of neutral and ground in a circuit. Whether it is a feeder circuit to a subdistribution or a branch circuit to an outlet, the neutral is the power return path. When a circuit powers a light bulb, tool or other appliance, power flows from the source through a wire (usually black or red in 120 V systems) to the component (load) using the power, and then the electrons return to the source through the neutral wire.

The ground wire, also known as the "equipment ground wire," is used to provide a path from any metal part of the appliance to the circuit breaker panel supplying power to the circuit, which may be live and present an electrical shock hazard. This occurs when a hot or neutral wire carrying current due to a connected load comes in contact with a metallic part of an appliance due to a loose wire or other fault. The grounding conductor provides a safe path for stray currents to flow back to the control panel, which trips the circuit breaker and disconnects the power supply. If there is no grounding conductor, this stray current can cause an electric shock.

In the main switchboard, the neutral and ground conductors are connected to each other and to a ground electrode (e.g., a metal ground rod) for abnormal energy impulses, such as lightning. This is the only point at which the neutral conductor is connected to ground. If the neutral and ground conductors are connected anywhere else, the return current that would otherwise flow to the neutral will flow back to the panel through the neutral and ground conductors. This is dangerous for several reasons. The most important reason is that if the neutral and ground wires are poorly connected or break, the part of the ground system (of the panel) on the other side of the break will become electrically charged and there will be a risk of electric shock. This is a serious problem because any exposed metal parts of the fixture, tooling, jig, fixture, jig, jig, jig, jig, jig, jig, jig, jig.

The National Electrical Code (NEC) requires the separation of neutral and ground conductors in secondary switchboards, and in primary switchboards when both switchboards are in the same building, since the 1999 revision. The requirement to separate neutral and ground conductors in a distribution panel in a separate structure first appeared in the 2008 NEC. Does this make an electrical panel system with a combined neutral and ground connection unsafe? No, although keeping them separate will increase the safety of the installation.