What Size Breaker for a Refrigerator
You can easily calculate the circuit breaker size needed for a standard refrigerator by reading the rated current value from the nameplate of your refrigerator and doing some basic calculations to arrive at the size of the breaker.
In this guide, we’ll show how you can easily select the correct circuit breaker size for refrigerators operating at various voltage levels, such as 110V/230V AC and 12V/24V DC.
What are Circuit Breaker Sizes?
The Breaker size refers to the Ampere rating of the circuit breaker. This needs to match the electrical requirements of your appliances to safely protect the electrical circuit from damage caused by an overload or short circuit.
Standard RV breakers for 120V AC circuits come in various sizes, including 15, 20, 30, and 50 amps. For 12V DC circuits, the choices expand to include 15, 20, 25, 30, 40, 50, and 60 amps.
Selecting a breaker size that matches the amp rating listed on your refrigerator’s nameplate is crucial. An undersized breaker will trip frequently due to overloads, while an oversized one won’t provide the necessary protection.
What Types of Circuit Breakers Are Available?
Before you determine the size of the breaker, it is necessary to understand how many circuit breakers are available.
Circuit breakers come in various types, each type has a specific function ranging from protecting ordinary house wiring circuits to preventing electrical shock and stopping potential electrical fires caused by hazardous arcs.
Let us look at a typical breaker panel’s most commonly used circuit breaker types.
Standard, Single-Pole Breaker
This breaker safeguards a single electrical circuit in your home’s or RV’s electrical system. That circuit might power something like a refrigerator or lights.
Standard single-pole breakers occupy one slot in your electrical panel and typically protect 15-amp and 20-amp circuits.
Standard, Double-Pole Breaker
Similar in function to single-pole breakers, double-pole breakers protect major electrical appliances that can’t operate on a regular 120-volt electrical circuit.
Like an air conditioner, a larger appliance uses two hot wires to deliver enough current. Both wires need protection from overcurrent, hence the need for a double-pole breaker, which accepts two wires instead of one.
DC Circuit Breaker
A third type of circuit breaker you might encounter in an RV setting is the DC (Direct Current) circuit breaker.
This type of breaker is specifically designed to handle the unique characteristics of DC electrical systems, which are common in many RVs, especially those equipped with solar panels or other off-grid power systems.
How Much Power Do RV Refrigerators Consume?
Always consider the actual power consumption of your fridge when sizing your breaker. The power draw of an RV refrigerator is not constant; it fluctuates based on its operational state. It also varies based on the fridge’s type, model, and size.
If you have a built-in RV refrigerator that uses absorption for cooling, the running power for the refrigerator is around 100-250 watts. This equals 4-10 amps at 24V DC or 8-20 amps at 12V DC.
On the other hand, installing a larger residential-type refrigerator consumes more power, requiring around 700-800W of running power. These refrigerators may operate at 110V or 230V AC, which means that the ampere rating of these generators is around 6-7.5A for 110V and 2.5-3.5A for 230V operation.
It is also essential to consider your fridge’s starting or surge power requirements when sizing the circuit breaker. The breaker should be able to handle the initial surge of power when the refrigerator starts up.
Choosing a Breaker for 110V/230V AC Refrigerators
Residential-type RV refrigerators can run on standard 110-120V or 220-230V AC power. This is the voltage you get when your RV is connected to shore power at a campsite or is powered by a backup generator such as a solar generator.
Let’s see how you can calculate the breaker size for AC operations by considering two examples:
Example 1. Breaker Sizing for 220-230V Operation
A double pole breaker is necessary if your refrigerator operates on 220-230V AC. Again, you would look at the amp or watts rating on the refrigerator’s nameplate.
Suppose your fridge has a running amps rating of 3.5A at 230V. Multiply this number by 3 to estimate the start-up amps needed. This gives us 11.5A.
To calculate the breaker size, increase this by a safety factor of 25%:
\(Breaker\ Size = 11.5A * 1.25 = 14.5\ amps\)
For 230V operation, the smallest breaker size is 15A, which we will select.
Example 2. Breaker Sizing for 110-120V Operation
You will need a single pole breaker if your refrigerator operates on 110-120V AC. To calculate the breaker size, check your refrigerator’s nameplate’s AC amp or watts rating.
For instance, if your fridge has an amp rating of 7.5 amps at 110V, you’d calculate the breaker size as follows:
\(Breaker\ Size = 11.5A * 3 * 1.25 = 28A\)
So, in this case, we would select a breaker larger than 28A, which would be a 30 amps single pole breaker.
Choosing a Breaker for 12V/24V DC Operation
Absorption-type built-in RV fridges can work operate on 12V or 24V DC power. This power can come from a battery or from a solar generator.
Here’s how you can size the circuit breaker for the refrigerator:
Example 3. 12V DC Breaker Sizing
If your refrigerator operates on 12V DC, the breaker sizing procedure is similar to a refrigerator operating at 110V or 230V.
So for a 12V DC refrigerator requiring 5A of running current,
\(Breaker\ Size = 5\ amps * 3 * 1.25 = 18.75\ amps\)
So, the right size breaker would be a 20 amp DC circuit breaker.
Example 4. 24V DC Breaker Sizing
Larger built-in RV fridges may operate on 24V DC, usually powered by two 12V batteries connected in series or a 24V solar generator. In this case, the amp rating is half that of an equivalent 12V model.
To calculate the breaker size, follow a similar process as above. For instance, if your refrigerator operates at 24V DC and uses 2.5 amps, the calculation would be as follows:
\(Breaker\ Size = 2.5\ amps * 3 * 1.25 = 9.5\ amps\)
Breaker Size = 2.5 amps x 3 x 1.25 = 9.5 amps
So, any DC breaker with a rating higher than 9.5 mps would be suitable.
Before connecting a refrigerator to the power supply, it’s essential to adhere to the following guidelines:
Ensure your refrigerator is on a dedicated circuit to prevent other appliances from tripping the circuit.
Typically, a 20 amp circuit is enough for most refrigerators, but knowing your refrigerator’s amperage is crucial to size your breaker correctly.
Use a properly grounded branch circuit for major electrical appliances.
A grounded branch circuit, originating from the breaker panel, is an integral part of a home’s electrical system, providing power to a specific area.
A 20 amp circuit breaker suffices for most refrigerators. However, modern refrigerators with features like an ice maker or water dispenser might require a dedicated 20-amp circuit.
Dedicated Circuit Importance
Given the risk of electrical fires, ensure the refrigerator’s circuit is dedicated.
In case of a fault, the breaker will trip, isolating the fault to the fridge and not affecting other appliances.
Time Delay Fuse
Use a time delay fuse to prevent sudden blowing due to momentary overloads. This fuse allows a temporary, harmless inrush of current that exceeds the fuse’s nominal rating.
Dedicated Electrical Outlet
Lastly, connect the refrigerator to a dedicated electrical outlet, serviced by a dedicated circuit from the breaker panel, to avoid overloading the circuit.
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