As an electrical engineer with over a decade of experience in the field, I can provide you with a detailed explanation on how to determine the correct breaker size for a 5500 watt water heater.

Firstly, it's important to understand the basics of electrical loads and how they relate to breaker sizing. The breaker is a safety device designed to protect electrical circuits from damage caused by overloads or short circuits. It does this by interrupting the flow of electricity when the current exceeds a certain threshold. The size of the breaker is determined by the ampacity of the circuit, which is the maximum current that the circuit can safely carry.

When sizing a breaker for an appliance like a water heater, you need to consider the power (wattage) of the appliance and the voltage of the electrical supply. The formula to calculate the current (in amps) required by an appliance is:

\[ \text{Current (amps)} = \frac{\text{Power (watts)}}{\text{Voltage (volts)}} \]

Given that your water heater has a power rating of 5500 watts and assuming a standard voltage of 240 volts (which is common in many households), we can calculate the current as follows:

\[ \text{Current} = \frac{5500 \text{ watts}}{240 \text{ volts}} \approx 22.92 \text{ amps} \]

This means that under normal operating conditions, the water heater will draw approximately 22.92 amps of current.

Now, when selecting a breaker, it's crucial to consider the continuous load that the circuit will carry. Breakers are typically sized to handle a certain percentage of their rated capacity to account for potential overloads. For a permanent load, such as a water heater, the breaker should be sized to allow for 80% of its rated capacity to be used continuously.

If we follow the example provided, where a 30-amp breaker is used, and the elements are strapped for a 4500-watt draw (which would be approximately 18.75 amps), the breaker is sized to allow for a continuous load of 80% of its capacity. This means that a 30-amp breaker would be limited to a continuous load of 24 amps (30 amps * 80%).

However, in your case, with a 5500-watt water heater drawing approximately 22.92 amps, you would need to select a breaker that can handle this load continuously. Since the load is less than 24 amps, a 30-amp breaker would be suitable, but you would need to ensure that the wiring is also appropriate for the load.

The wire gauge (AWG) is another critical factor. The wire must be capable of carrying the current without overheating. For a 22.92-amp load at 240 volts, a 10 AWG wire is typically recommended. This ensures that the wire can safely carry the current without causing a fire hazard.

In conclusion, for a 5500-watt water heater operating at 240 volts, you would calculate the current draw to be approximately 22.92 amps. A 30-amp breaker would be suitable, provided that the wiring is 10 AWG or larger to handle the load safely. Always consult with a licensed electrician or follow local electrical codes when making such installations to ensure safety and compliance.

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Since this is a purely resistive load 5500 watts at 240 volts is 23 amps, breaker is sized at 30 amps and 10 awg wiring is used. In your case if the elements are strapped for 4500 watts draw is 18.75 amps, permanent draw loads should be sized at 80% of breaker capacity so a 20 amp breaker is limited to 16 amps.Nov 24, 2011read more >>