Before we go any further in our exploration of the loadcenter, let’s take a moment to consider the main components and features of a typical loadcenter.

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Loadcenter Components and Installation

Before we go any further in our exploration of the loadcenter, let’s take a moment to consider the main components and features of a typical loadcenter.

Anatomy of a Loadcenter


1.	Front Cover	Provides a neat, protective face for the product. Usually includes a hinged door to allow access to the circuit breaker handles.
2.	Inner Cover or Dead Front	Serves as a protective barrier to prevent contact with energized (“hot”) parts within the unit.
3/4.	Inner Cover Adjustment Screws	Used to secure the inner cover tightly against the tops of the circuit breakers. This eliminates any space that might allow access to “hot” parts inside.
5.	Twistouts	Removable perforated metal spaces that can be twisted out, to allow the protrusion of the circuit breaker handles.
6.	Pub (or Publication)	Lists the specifics of the loadcenter, including: circuit breaker application, UL information, short circuit ratings, series ratings, wire connection torque values, unit accessories, and wiring diagram.
7.	Sliding Latch	Provided on indoor loadcenters to allow easy opening of the loadcenter door.
8.	Door	The hinged part of the front cover which allows access to the circuit breaker handles.
9/19.	Backpan Top and Bottom Mounting Screws	Allows for easy removal of the loadcenter interior assembly.
10/18.	Enclosure Mounting Keyholes	Located at top center and bottom center. Whether surface-mounted right-side up or inverted, the unit can be easily centered on the wall by hanging the enclosure with the uppermost keyhole.
11.	Drywall Scribe and Markings	Serve as a guide for mounting the loadcenter flush with the drywall between the wall studs.
12.	Surface Mounting Holes (4)	Once centered for surface mounting, the loadcenter is affixed with screws through these four holes.
13.	Main Lugs or Main Breaker	Provide the means for the termination of the power cables coming from the electric meter. Main lugs simply provide a safe mechanical connection to the Bus Bars. A main breaker provides thermal magnetic protection for the loadcenter.
14.	Backpan	The solid steel piece that supports the loadcenter bus bar assembly. It also provides the means to affix branch circuit breakers.
15.	Bonding Strap	Used to bond the neutral to the enclosure (when required by code).
16.	Bus Bars (2)	An extension of the incoming power cables. Provide a mechanical means of affixing branch circuit breakers. Notches are added to (or omitted from) the bus bars to limit the number of branch circuits allowed. Bus bars may be aluminum or copper.
17.	Knockouts	Circular indentations in the top, bottom, sides, and back of the enclosure. When removed, the electrician can bring wire into and out of the loadcenter without compromising safety.
20.	Neutral Bar	Provides the termination point for the neutral wires from both the incoming service and the load circuits. Most loadcenters have a twin neutral design, positioning terminations on both sides of the unit. This is a wiring convenience for the electrician.

Enclosure

The loadcenter enclosure is typically constructed of cold rolled or galvanized steel. It serves to house the other loadcenter components. It is designed to provide component and personnel protection.

The National Electrical Manufacturers Association (NEMA) and UL have established guidelines for electrical enclosures. They are as follows:

NEMA Type 1 General Purpose	This enclosure type is for general purpose, indoor use. It is suitable for most applications where unusual service conditions do not exist. It provides protection from accidental contact with enclosed equipment
NEMA Type 3R Raintight	This enclosure type is intended for outdoor use. It provides protection against falling rain, sleet, and snow.

Installation and Mounting

A loadcenter can be Flush-Mounted or Surface-Mounted against a wall. A flush-mounting is recessed into a hole between the studs in the wall. A surface-mounting is attached to (and projects out from) the wall.

Flush mounting offers some benefits such as:

Space savings – Because the box is behind the wall, the room does not sacrifice too much space.

Appearance – This option is more attractive, as the wiring and box are concealed.

Safety – Except for the trim, the panel does not stick out to possibly catch clothing or other objects.

Figure 12. Flush-Mount Vs. Surface-Mount

Surface-mounted loadcenters are generally used in industrial buildings, and in basements or garages. Because most of these areas have walls made of poured concrete, flush-mounting is impractical.

The NEC specifies clearances around loadcenters. This is to provide access and working space. There are three basic rules:

Headroom in the location must be a minimum of 6-1/2 feet.

For systems up to 150 volts, the minimum distance from the loadcenter to the ground shall be 3 feet.

For access, there must be 30 inches minimum space in front of the loadcenter, and sufficient space to allow the hinged door to open and rotate 90 degrees.

Figure 13. Loadcenter Clearance Requirements