This picture shows the interior of a typical distribution panel in the United Kingdom. The three incoming phase wires connect to the busbars via a main switch in the centre of the panel. On each side of the panel are two , for n. This picture shows the interior of a typical distribution panel in the United Kingdom. The three incoming phase wires connect to the busbars via a main switch in the centre of the panel. On each side of the panel are two, for neutral and earth. The incoming neutral connects to the lower busbar on the right side of the panel, which is in turn connected to the neutral busbar at the top left. The incoming earth wire connects to the lower busbar on the left side of the panel, which is in turn connected to the earth busbar at the top right. The cover has been removed from the lower-right neutral bar; the neutral bar on the left side has its cover in place. Down the left side of the phase busbars are two two-pole and two single-pole breakers, one unused. The two-pole RCB. A distribution board (also known as panelboard, circuit breaker panel, breaker panel, electric panel, fuse box or DB box) is a component of an that divides an electrical power feed into subsidiary while providing a protective or for each circuit in a common. Normally, a main, and in recent boards, one or more (RCDs) or (RCBOs) are also incorporated. In the United Kingdom, a distribution board designed for domestic installations is known as a consumer unit. North American distribution boards are generally housed in enclosures, with the positioned in two columns operable from the front. Some panelboards are provided with a door covering the breaker switch handles, but all are constructed with a dead front; that is to say the front of the enclosure (whether it has a door or not) prevents the operator of the circuit breakers from contacting live electrical parts within. carry the current from incoming line (hot) conductors to the breakers, which are secured to the bus with either a bolt-on connection (using a threaded screw) or a plug-in connection using a retaining clip. Panelboards are more common in commercial and industrial applications and employ bolt-on breakers. Residential and light commercial panels are generally referred to as load centers and employ plug-in breakers. The neutral conductors are secured to a neutral bus using. The branch circuit conductors are secured to a terminal block attached directly to the panelboard enclosure, which is itself. During servicing of the distribution board, when the cover has been removed and the cables are visible, American panelboards commonly have some live parts exposed. In Canadian service entrance panelboards the main switch or circuit breaker is located in a service box, a section of the enclosure separated from the rest of the panelboard, so that when the main switch or breaker is switched off no live parts are exposed when servicing the branch circuits. Breakers are usually arranged in two columns. In a U.S.-style board, breaker positions are numbered left-to-right, along each row from top to bottom. This numbering system is universal with numerous competitive manufacturers of breaker panels. Each row is fed from a different line (A, B, and C below), to allow 2- or 3-pole common-trip breakers to have one pole. Despite the adoption of a standard for mounting and a standard cut-out shape for seemingly interchangeable breakers, the positions of busbar connections and other features are not standardized. Each manufacturer has one or more "systems", or kinds of breaker panels, that is only fully compatible with breakers of that type. These assemblies have been tested and approved for use by a recognized authority. Replacing or adding equipment which "just happens to fit" can result in unexpected or even dangerous conditions. Such installations should not be done without first consulting knowledgeable sources, including manufacturers' datasheets. For reasons of and security, domestic circuit breaker panels and consumer units are normally located in out-of-the-way,,, or, but sometimes they are also featured as part of the aesthetic elements of a building (as an art installation, for example) or where they can be easily accessible. However, current U.S. building codes prohibit installation of a panel in a bathroom (or similar room), in closets intended for clothing, or where there is insufficient space for an electrician to gain access to the panel. Specific situations, such as an installation outdoors, in a hazardous environment, or in other out-of-the-ordinary locations might require specialized equipment and more stringent installation practices. Distribution boards may be designated for three phase or single phase and normal power or emergency power, or designated by use such as distribution panels for supplying other panels, lighting panels for lights, power panels for equipment and receptacles and special uses. Panels are located throughout the building in electric closets serving a section of the building.
