Breaker panels go farther back than many people realize, having been patented in 1910. However, it is unusual to see a residential breaker panel from before WWII. Prior to this, electrical breakers were primarily used in manufacturing and naval applications.

Breaker panels started appearing in homes in the mid-1950s in small numbers, and were universal in most areas by the late 1960s.

As discussed, they did not replace fuses due to any deficiency of the older technology. The problem was that when a fuse blew, one needed to go find a replacement. Breakers are obviously more convenient because when they trip after a fault, they can be reset without replacement.

We now have added benefits from circuit breakers with the advent of both GFCI and AFCI protection, in many locations.

The photo above shows an early residential circuit breaker panel manufactured by Trumbull Electrical in the late 1940s.

Circuit Breakers

Breakers fall into four categories, which we'll look at in more detail:

1. 240-volt double breakers; 2. 120-volt single breakers; 3. GFCI breakers; and 4. AFCI breakers.

All of these require some specialized knowledge to properly evaluate. Remember, we are talking about energized components. Safety is paramount when investigating electrical panels.

The breaker at the left is a Square D single-pole. This breaker is rated for two conductors only, but many are rated for a single conductor only, so this is something to be aware of when inspecting the breaker. Square D and Cutler-Hammer currently manufacture breakers which are UL-listed for this application.

240-Volt Circuit Breakers

Many of our homes now require high-voltage and amperage circuits to run appliances such as dryers, air conditioning, stoves, and some load-side distribution panels, etc.

Appliances that are 240-volt are fed from two 120-volt conductors, each connected to a separate bus bar in the distribution panel. It is imperative that, when one of the circuits trips due to an overcurrent condition, both conductors are de-energized at the same time. If not, someone could be trying to repair an appliance that is still partially live.

For this reason, all breakers supplying 240 volts are required to have the handles tied together by a listed handle tie. Nails, screws, or scraps of wire, for example, are unacceptable. Sometimes, the breaker is molded with this connection in place, and sometimes they are linked by a listed handle tie. The inspector should ensure that the tie is present and has not been damaged.

A 240-volt circuit breaker also acts as the main disconnecting means in modern panels, disconnecting all the electrical power in the home.

The picture above is of an older Bryant panel. Also notice that the 240-volt circuit breaker is being back-fed and held in place with a properly listed holding device; in this case, it’s a screw provided by the manufacturer.

120-Volt Circuit Breakers

Regular 120-volt circuits are fed from one bus bar only. Also in use are tandem breakers, which are 120-volt breakers that feed two separate circuits, each controlled by its own handle. (These should not be linked.) As with fuses, the inspector should ensure that the rating of the breaker does not exceed the rating of the conductors, unless allowed by 240.4 (E) or (G) of the NEC. Otherwise, something other than the breaker is likely to overheat and fail.

There are two manufacturers of single-pole, 120-volt breakers who have their products listed for two conductors. These are made by Square D and Cutler-Hammer. These should not be confused with double-tapped breakers, where more than one conductor has been incorrectly connected to a single breaker.

The picture above shows a "triple-tapped" breaker. A condition like this should be further evaluated by a licensed electrical contractor.

GFCI Breakers

Ground-fault circuit-interrupting breakers are one of the ways to protect circuits and their users from ground faults. Not all circuits are required to have GFCIs and, in many homes, the locations that require this protection have their own GFCI outlets. However, if a GFCI breaker is used, it will provide protection to all receptacles in that branch circuit.

GFCI breakers feature trip and reset buttons to ensure that they are working correctly. The inspector should trip the breaker using the test button and ensure that the circuit has indeed been switched off.

The image above shows both a GFCI breaker and a receptacle. Remember that either is acceptable to protect a damp location, or a circuit to a damp location. Additional locations are listed under Section 210.8 (A) and (B) of the NEC.

AFCI Breakers

Arc-fault circuit interrupters have been required in new construction since the 1999 edition of the NEC. Many jurisdictions are now observing recent code editions which has expanded the use of AFCI devices to nearly everywhere within a dwelling except the kitchen, bathroom, and most areas where GFCI protection is already required. These breakers are designed to trip if they sense arc faults in the circuit, which are caused primarily by damaged wiring.

What Is an AFCI?

Arc-fault circuit interrupters (AFCIs) are special types of electrical receptacles or outlets and circuit breakers designed to detect and respond to potentially dangerous electrical arcs in home branch wiring. As designed, AFCIs function by monitoring the electrical waveform and promptly opening (interrupting) the circuit they serve if they detect changes in the wave pattern that are characteristic of a dangerous arc. In addition to the detection of dangerous wave patterns (arcs that may cause fires), AFCIs are also designed to differentiate safe, normal arcs. An example of this arc is when a switch is turned on or a plug is pulled from a receptacle. Very small changes in wave patterns can be detected, recognized, and responded to by AFCIs.

A Brief History

In the 1999 NEC®, these breakers were required only on bedroom receptacles. In the 2002 NEC, they expanded to all 15-amp and 20-amp, single-phase, 120-volt branch circuit-supplying outlets. The 2005 NEC® expanded their use to allow AFCI devices similar to GFCI receptacles, but none existed on the market, and their use was limited by 210.12(B). Finally, in the 2008 NEC, the use of combination-type AFCIs expanded to 15- and 20-ampere branch circuit-supplying outlets installed in a dwelling unit’s family room, dining room, living room, parlor, library, den, bedroom, sun room, recreation room, and similar rooms, including hallways and closets. Many people confuse the term "combination" to mean AFCI and GFCI together in a single device. This is partly correct only in that most AFCI devices offer Class B- type of GFCI protection, which usually starts at around 20 to 30 milliamps, and do not offer any personal protection as do conventional GFCIs.

The combination-type AFCIs are designed to activate when there is a parallel arc that reaches a peak of 75 amps. The "combination" refers to the fact that AFCIs now protect against series arcs, as well. They have a 5-amps peak threshold. This is where the term "combination" comes from.

Remember, the term "outlet" is not interchangeable with "receptacle." Outlets are defined by the NEC® as "a point on the wiring system at which current is taken to supply utilization equipment." Recess lights, smoke alarms, receptacles within outlet boxes, and so on, are supplied from outlets.

It is likely that many more locations (maybe even the whole house) will be required to have arc-fault protection with future code revisions. As with GFCI breakers, these should also be tripped with their test buttons, and the circuit should be checked to make sure it has been shut down.

The image above shows of a pair of AFCI breakers. Notice the test buttons, and also the second conductor that connects the breaker to the neutral bus. (This is not a double tap.) Many early Square D AFCI breakers had to be recalled due to manufacturing defects. Currently, however, many AFCI manufacturers are in their 10th+ generation, and are proving to be worth every penny when saving lives and property.

Complements of InterNachi