Replacing a CU-AL Circuit Breaker (Types Of Circuit Breakers)

Rewiring can be confusing. That is because of the different labels on the different components. While a breaker may be able to work with two different types of wires, you cannot connect those two wires. They are not compatible. When you rewire, you need to know what labels and abbreviations mean and how they apply.

The CU-Al label only means that the breaker can handle both copper and aluminum wires. However, that label does not mean you can use both wires at the same terminal. Plus, if you use aluminum wiring, you need to increase the size by one to handle the same load copper wires can.

To learn more about this situation, just continue to read our article. It has the information you want to know about so you can make the right replacement and connect the wires properly. Take a few minutes to find out this information.

CU-AL Breaker Type


These are the abbreviations for breakers that can be used with aluminum and copper wires- COALR, CO/ALR devices, and AL-CU or CU-AL. They may have different labels but they all do the same task.

However, they do not all work the same as the original CU/AL breaker and the aluminum wiring did not get along. Once this problem was discovered, the industry created the CO/ALR which stands for copper-aluminum, revised.

This upgrade was supposed to have terminals whose screws acted like aluminum and expanded when the wires expanded. CO/ALR is the standard for light switches but CU/AL is for breakers and larger equipment.

To connect an aluminum wire to a terminal, everything has to be rated CO/AR including the wire nuts. Then you need to put the anti-oxidant paste on stripped ends for the connections to work right.

What Does CU Mean On a Breaker?


The CU stands for copper wire only. Or you may be able to use copper-clad wiring as well. The labels on the breaker tell you exactly which type of wire you can use with that breaker. If you have a breaker that says CU/AL, then you should be able to use aluminum wiring with caution.

It is an industry-wide regulation that when you install a CU breaker, you can only use a copper wire or a copper-clad aluminum wire. If you have a child that is great in science, they will instantly recognize that CU is the chemical symbol for copper.

Aluminum is cheaper than copper which is why it has been used in construction for decades now.

Replacing a CU-AL Circuit Breaker


The reality is that it is not hard to replace the breaker. The difficult part comes in avoiding getting shocked when you do so. Many people are not comfortable with working at the main power box and that is okay.

The first step is to buy the exact same breaker as the one you are replacing. The thing to remember here is that you have to identify your breaker box before buying the breaker.

There are only two types of breaker boxes, the Square D QO and the Homeline and they do not accept the same breaker designs. You need to buy the breaker for the breaker box you have in your home.

Once that is done, turn the main power off so you can work safely. Unscrew or pull out the old breaker and insert the new one. After that, screw the new one in place and turn on the main power.

You should have a couple of wires to remove and reattach from the old to the new. It is all very straight forward and should not take a long time to do.

What Are The 2 Types Of Circuit Breakers?


There are actually more than 2 types of breakers. There are only 2 types of breaker boxes to put those breakers into. We mentioned those already, and they are the Square D QO and the Homeline brands.

But when it comes to breakers, you have several types and they are listed as:

- Standard, Single-Pole Breaker

- Standard, Double-Pole Breaker

- Ground Fault Circuit Interrupter (GFCI) Breaker

- Arc Fault Circuit Interrupter (AFCI) Breaker

- AFCI/GFCI Dual-Function Breaker

The first three you will run into the most.

Types Of Circuit Breakers And Their Uses


The types of circuit breakers are listed above. The first option, it is used to monitor a single wire. The second one monitors 2 wires, hence their names. Then the GFCI option is monitoring for line ground faults.

This is an important task because if there is a problem and there is no GFCI breaker, then a fire could start. Then the AFCi or arc fault breaker has only been required since 2002 and at that time only in bedrooms.

As the name says, they monitor your wires for arcs. Finally, you have the dual function breaker that does both the line ground fault and the arch fault monitoring.

It is just two levels of protection in one breaker.

Can You Have Breakers With Aluminum Wiring?


Yes, you can as long as all the parts of the electrical system are aluminum compatible. These types of wires should be monitored by arc fault breakers. The reason for this added protection is that aluminum wires are known to come loose and create an arc.

The NEC has made it mandatory that the AFCI breakers be in more rooms than just the bedroom. Plus, they have mandated that this type of breaker replace the standard models that most people are used to using.

Some Final Words

Electrical components can get confusing. But when you learn all about them, you will see how straight forward wiring new breakers are. The key is just to get the right breaker the NEC calls for and make sure it is made for one of the two breaker boxes.

The breakers are designed to cut off any electrical power when a problem occurs with the electrical flow. This helps prevent fires and loss of life making your home safer to live in.

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