What Size Breaker For Water Well Pump?

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Having the correct size breaker for your water well pump is essential. If you don’t, you could end up with many blown fuses and an unhappy home. 

But what size breaker for water well pump? In this article, we’ll help you determine the right breaker size for your needs.

What Size Breaker For Water Well Pump?

Different water well pumps have different power requirements. The size of the breaker you’ll need will depend on your specific pump. 

For example, a 15 amp breaker is required for a pump with a capacity of 12 HP. For a 1 HP pump, it is recommended to have a circuit breaker of 25 amps.

On the other hand, you can find the breaker size by looking in the owner’s manual or contacting the manufacturer.

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Proper Breaker Sizes For Well Pumps

So far, we’ve talked about how circuit breakers keep electronics safe. But now there’s another element to consider.

A well pump needs a lot more power to start spinning. In other words, for it to properly begin spinning, it requires extra electricity flow.

When you are thinking about selecting the breaker size, then you need to keep in mind the below two factors:

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Pumps Under Full Load

The amp draw of most well pumps varies by the model because the horsepower differs.

But they all use 220-240 volts. The current will usually fall between 6 and 20 amps.

A whole load occurs when the pump is functioning with maximum efficiency.

While performing a regular operation, the pump will consume a specific quantity of power. 

In order to save you time, we have created a table with the required circuit breakers for pumps that are under full load:

Well Pump (HP)	Volts (V)	Wattage (W)	Amps	Circuit Breaker (Amps)
0.5 HP	110 V	670 W	10 A	15 A
0.5 HP	230 V	670 W	5 A	15 A
0.75 HP	230 V	940 W	6.8 A	20 A
1 HP	230 V	1210 W	8.2 A	25 A
1.5 HP	230 V	1770 W	10.6 A	30 A
2 HP	230 V	2025 W	12 A	30 A
3 HP	230 V	3000 W	15 A	40 A
5 HP	230 V	4900 W	25 A	50 A

As you can see, the required circuit breakers have a significantly higher amp rating than operational amps to prevent easy tripping during sudden electricity surges. 

The pump’s horsepower has an impact on the overall power draw as well. A ½ HP or a ¾ HP motor will suffice for domestic purposes.

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Pumps Under Maximum Load

However, another advantage to having a circuit breaker with a higher amp rating is that it permits the pump to function more efficiently by allowing it to draw more power.

Below we give the required circuit breakers for pumps under maximum load:

Well Pump (HP)	Volts (V)	Wattage (W)	Amps	Circuit Breaker (Amps)
0.5 HP	110 V	960 W	12 A	15 A
0.5 HP	230 V	960 W	6 A	15 A
0.75 HP	230 V	1310 W	8 A	20 A
1 HP	230 V	1600 W	10.4 A	25 A
1.5 HP	230 V	2280 W	13.1 A	30 A
2 HP	230 V	2555 W	16 A	30 A
3 HP	230 V	3400 W	19 A	40 A
5 HP	230 V	5500 W	30 A	50 A

The pumps, therefore, require a lower amp than the maximum. And that’s how the circuit breaker prevents any harm. 

Sometimes you won’t have access to the pump data. You must read the amperage in those circumstances.

So, you will need a multimeter to calculate the amperage. With that, you can avoid hiring a professional and calculate amps independently.

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What Size Breaker Should A Well Pump Use?

The size of the breaker you’ll need for your well pump will depend on the model and make of the pump, but most use a 20-30 amp breaker.

The circuit breaker, which is a critical component in appliances such as pumps, is self-destructive. Circuit breakers with thin wires can only sustain particular temperatures. 

Besides the system melts down when excessively heated, resulting in a power outage.

A pump features an optimized design to require a specific amount of power to function correctly. 

Also, the transformer can operate at peak load, drawing 12 to 15 amps of electricity during maximum load. 

Because the demand has a higher amp capacity, current efficiency is significantly lower.

Consequently, when there is an unexpected surge in power, the circuit breaker will not trip easily.

A single-phase 220-volt motor powers most home pumps. However, 110-volt pumps do exist. A key factor to consider when choosing a pump is how much energy it has. 

For example, if a pump has 12 HP, you need a 15 amp breaker. A circuit breaker with 25 amps is the recommended amount for a 1 HP pump.

If the well pump fails, there is also a higher chance that the generator will trip. If you notice that the pump isn’t functioning as it should be, resetting the breaker may help. 

However, it’s always best to contact a professional just in case. It’s essential to ground the pump before it fails.

How To Size A Circuit Breaker For A Pump?

As we mentioned earlier, the size of the breaker you’ll need will depend on the make and model of your pump. However, most well pumps use a 20-30 amp breaker.

To find the correct size breaker for your pump, you can either consult your owner’s manual or contact the manufacturer.

Also, you can find the breaker size manually, now follow the below guidelines.

For instance, how many amps does a 3HP 230v single-phase well pump motor have? The answer is 17 amps.

We’ll use the following formula to determine the maximum, safest breaker size for that pump based on the 250% allowance stated above:

17 x 2.5 = 42.5 amps

That’s why you’ll see that many of the breakers available are 45 amps. There aren’t any with that specific size.

Therefore, we move up to a larger capacity, which is 90 amps.

Is it implying that you should restrict yourself to one? Most inspectors would likely agree that not really.

They’ll most likely pick a more miniature breaker that will still be able to start the pump’s motor.

If a 30-amp breaker can support it, the outlet is still code-compliant. The same applies to 35, 40, and 45-amp breakers. 

However, anything more is no longer technically permissible.

Take note that these values do not consider variables such as wire size and distance, as previously mentioned.

In terms of wire size, it is always best to follow the 250% rule.

This number factors in a safety margin, as there might be a voltage drop when the current reaches the pump.

So, if you have a 3HP motor, you’ll need at least an 8 AWG wire. This is because the maximum current rating for an 8 AWG wire is 30 amps.

Now follow the above guidelines to find the circuit breaker size for your well pump. Also, make sure to contact a professional if you’re unsure about anything.

Why Is It Necessary To Pick The Proper Size Breaker For A Well Pump?

First and foremost, it’s a safety issue. If the breaker is too small, it can cause an electrical fire. Also, if the breaker trips frequently, it can damage the pump’s motor.

Because high currents are necessary to start most submersible well pumps properly, your breaker and its wire conductor should be able to withstand it.

Otherwise, you risk a fire.

Furthermore, if you don’t maintain the pump, it won’t operate effectively and will repeatedly trip the breaker. 

In addition, deep well pumps require contemplation for longer distances. There are more variables altogether compared to other gadgets and appliances.

Another reason you need to pick the correct size breaker is that it affects the performance of the well pump. 

If the breaker is too small, the pump will have to work harder, which can cause it to wear out more quickly.

Finally, picking the correct size breaker can help you avoid violating your home insurance policy. 

Most policies require that you have proper safety features in place, and using the wrong size breaker doesn’t meet that criterion.

FAQs

Final Thoughts

Picking the suitable size breaker is essential to ensure the safety of your well pump.

Make sure to follow the guidelines mentioned in this article to find the ideal circuit breaker for your needs.

After reading this article, we hope you can know what size breaker you need for your water well pump.