# Circuit Breakers - tripping or not tripping?

• dewdrop714
In summary, the owner of a greenhouse uses an electrical heating system to save on heating costs. The system provides the same heating effect as 800kg of water kept in barrels. During the day, the water is heated by the sun to 50 degrees Fahrenheit and during the night, it freezes into ice at 32 degrees Fahrenheit in 10 hours. In order to avoid tripping, the circuit breaker for the electrical heating system would need to have a minimum ampere rating of 62.77Amperes. The question of whether the circuit breaker will trip depends on the specific current rating.
dewdrop714
The problem statement:
To save on heating costs, the owner of a greenhouse keeps 800kg of water around in barrels. During a winter day, the water is heated by the sun to 50 degrees Fahrenheit. During the night the water freezes into ice at 32 degrees Fahrenheit in 10 hours. An electrical heating system is used providing the same heating effect as the water.

The attempt at a solution:

P=Q/t = (542*10^6)/36000s = 15066 Watts
I=P/V = 15066/240 = 62.77Amperes

The minimum ampere rating that the 240 volt circuit breaker would have to be to avoid tripping is what i calculated...it turned out to be 62.77Amperes.

The question:
What I don't get is "does the circuit breaker trip? Why or why not?"

Weird, they would have to tell you how much current will trip the breaker in order to answer the question.

p.s. I'm curious, how did you come up with 542 MJ for the energy?

Well 4186 is spec heat of water and 2093 is spef heat of ice. I also converted the temps to kelvins. Then I input them into the equations...I did Q1= (800)(4186)(305.93)=102*10^7 and Q2=(800)(2093)(287.93)=482*10^6. Then i got Q= Q1-Q2 = 542*10^6.

That doesn't look right.

If Q is the thermal energy change of the water, the formula is

Q = c m ΔT​

where c (for liquid water) is 4186 J/(kg-K), m is 800 kg, and ΔT is the change in temperature of the liquid water.

That would be the heat removed from the liquid water as it cools from 50F to 32F. But in addition you'll also need the heat removed as the water freezes to ice, at a constant temp of 32F. Did you class talk about the heat required to freeze water or melt ice? It's an additional equation, it should be talked about in your textbook or lecture notes.

## What is a circuit breaker and how does it work?

A circuit breaker is an electrical safety device designed to protect an electrical circuit from damage caused by excess current. It works by automatically breaking the circuit when it detects an overload or short circuit, preventing the flow of electricity and preventing damage to the circuit or appliances.

## What causes a circuit breaker to trip?

A circuit breaker can trip for a variety of reasons, including an overload of electrical current, a short circuit, or a ground fault. Overloading occurs when too many appliances or devices are drawing power from the same circuit, while a short circuit happens when the hot wire and neutral wire come in contact with each other. A ground fault occurs when the hot wire touches a grounded surface, such as a metal box or appliance.

## How do I reset a tripped circuit breaker?

To reset a tripped circuit breaker, first, you need to locate the breaker panel in your home or building. Look for the switch that is in the "off" position or in the middle. Flip the switch all the way off and then back on. This should reset the breaker. If the breaker continues to trip, it may be a sign of an underlying issue and you should consult a professional electrician.

## Can I prevent my circuit breaker from tripping?

While it is not always possible to prevent a circuit breaker from tripping, there are some steps you can take to reduce the likelihood of it happening. These include avoiding overloading circuits, using surge protectors for sensitive electronics, and regularly inspecting and maintaining your electrical system.

## What should I do if my circuit breaker keeps tripping?

If your circuit breaker keeps tripping, it could be a sign of a larger issue with your electrical system. It is important to not ignore this and to consult a professional electrician. They can help identify the cause of the tripping and make any necessary repairs or upgrades to ensure the safety and efficiency of your electrical system.

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