We give less thought to the capacity of the electrical panels unless we plug them inside the appliance and flip the switch. The panel wattage and its capacity are something we should start learning.
Generally, most US households use a 120 V power supply, so 200 Amps will be 24000 watts(200×120). Given the voltage drop, which can be between 1-3%, your household wattage can range between 23280-24000 watts. Similarly, if your household has 240 V, you will have 44,600 to 48,000 watts.
Being the house owner, you should know the wattage of your amp panel, how much it will handle, and whether you should upgrade it. This guide will explore these things and give you an idea about electrical power units.
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Understanding electrical power units
Before you calculate or convert your house’s electrical panel to understand its capacity, you should gather ideas about the different electrical power units.
Without the units, you won’t understand your electrical unit’s capacity and may overload it.
There is a huge range of electrical units. Below are some basic electrical power units:
- Volt (V): Voltage is the work amount needed to move the electrical charge from one point to another.
- Current (I) or ampere (A): The current is the amount of the charge or electron passing through the circuit per unit of time.
- Resistance or Ohms (O): Resistance or R is the opposition given to the current flow in a circuit.
- Power (P) or Watts (W): Power is the product of work needed and the electron number passing through the circuit per unit of time.
- Watt-Hour (Wh): The amount of electrical energy consumed by the circuit at a given time is a watt-hour. For example, a normal bulb can consume 100 watts per hour.
- Decibel (dB): Decibel is the 1/10th unit of the Bel and represents the gain in voltage, current, or power.
Out of these, voltage, ampere, and Ohm are the standard units of electrical measurements for voltage, current, and resistance.
Conversion of amps to watts
If you have a 200 amp service, you would want to know how much wattage is 200 amps.
Here is how I figured out how much wattage is 200 amps.
To know how much watts are 200 amps in the case of direct current, you have to know the potential difference in the voltage.
To convert 200 amps to watts with the alternating current, you must know the power factor, the phase numbers, and the voltage type.
To convert 200 amps to watts, change the current (I) to power (P). Before that, you should learn about the criteria.
After that, you should apply the 200 amps (A) to the watts (W) formula.
Usually, 200 amps mean you have 24,000 to 48,000 watts for your appliances.
The watts is the number of power flowing to your house. To convert the amps to watts, you should multiply the volts by the number of amps.
Volt x amps = watts
So, if you have 120V, which is common in the US residentials, 200 amps are 24,000 watts. It means the panel will handle 24k watts of electricity.
If you have 240V, then 200 amps are 48,000 watts.
That is how you convert the amps to wattage.
In the case of 240V, the power from the utility companies is mostly 220V or 230V with a 3% voltage drop.
After the voltage drop, the voltage becomes 223 or 232 volts.
So, the wattage of these amps will be 44,600 watts to 48,000 watts.
You cannot add breakers because it will be impossible for the circuits to live together.
Calculating watts from amps
To accurately calculate the watts from amps, you must figure out whether the electrical current type is direct or alternating.
If it is an alternating current, the 200 amps transformation will differ for the single-phase and 3-phase systems.
For a 3-phase, the line-to-line and line-to-neutral voltage will need different constants during the conversion.
Here are some formulas based on direct and alternating currents:
- DC: P(W) = 200 A x V(V)
- AC, Single phase: P(W) = 200 A x PF x V(V)
- AC, Three Phase, Line to line voltage: P(W) = 200 A x √3 x PF x -L(V)
- AC, Three Phase, Line to neutral voltage: P(W) = 200 A x 3 X PF x VL-0(V)
In the case of the alternating current, the power factor has to be equal to the real power.
P = I2R will be divided by the apparat power, 0 ≤ PF ≤ 1.
Here I = 200 A, R = resistance.
So, to know the 200 amps wattage, you should know the voltage to convert it into watts.
When you use a 120V circuit, the utility company gives you 110V with a 3% voltage drop.
If the PF is 0.5 and the voltage is 110V, you get the following result:
- DC: P = 200A x 110V = 22000W
- AC, Single phase: P = 200A x 0.5 x 110V AC2= 11000W
- AC, Three Phase, Line to line voltage: AC2P = 200 A x √3 x 0.5 x 110 V = 19052.56W
- AC, Three Phase, Line to neutral voltage: P = 200A x 3 x 0.5 x 110V = 33000W
If you have 240 volts, you will get one result for direct current and three for alternating current.
If the power factor is 0.5, the results will be 48,000, 24,000, 41569.22, and 72,000 watts.
200 amps at 220V to watts will be 44,000, 22,000, 38105.12, and 66,000 watts. 200 amps at 120V are 24,000, 12,000, 20784.61, and 36,000 watts.
Can I overload a 200 amp panel?
You can overload a 200 amp, but you should not do it.
If it can handle only 24,000 or 48,000 watts, you should maintain it and avoid loading it with multiple appliances.
Overloading can damage the breakers, lead to short circuits, and start a fire.
Breakers are the safety switches that automatically shut down after sensing overloading.
But, overloading the service panels will damage them and stop them from doing their job.
Here are some results of overloading the panel:
Damage to the appliances
When you overload the panel just because it can handle it, it will supply more current than it is rated for.
The devices and appliances connected to the panel will get more current than their rating.
Excessive current will heat the devices and destroy components like the inductors, capacitors, and resistors.
Appliances that pull maximum current are:
- Heat pumps
- Electric ranges
- Air conditioners
- Cloth dryers
- Electric furnace and water heater tanks
High risks of electric shocks and fire
Overloaded panels will cause excessive power flow, making the internal parts risky to touch as they will electrocute you easily.
Current overflow will generate a lot of heat which will stay undetected inside the electrical box.
It will further wear down the wires and internal parts inside the panel and start a fire.
Appliances that can overheat are:
Damage to the entire panel
Since overloading will make the panel receive excessive current, the wiring won’t be able to handle such high power.
Over time, the breaker will trip, shut down, and damage the entire panel.
You can detect the overloading issues from the following signs:
- The lights will dim whenever you turn on the heavy appliances.
- The smoke from the burning wires will make the walls and the plates darker.
- You will get a weird burning smell due to the burning wires.
- The panel will release a buzzing, humming, or crackling sound.
- Your breakers and fuses will frequently trip and blow off.
- Sometimes you will receive a mild shock whenever you touch the appliance or the switches.
Importance of electrical current in determining the power consumption
Your house’s electrical current will determine the power consumption amount.
Depending on the electrical service of your house, you should have appliances that can consume enough power without any overheating issues.
If you have a 200 amp service, you should have appliances that can consume enough power without overheating your electrical panel.
American households consume 10,800 kilowatt-hours per year.
The average house will use 8,000 to 12,000 watts at peak hours to run its appliances.
The larger houses will run more wattage per hour.
Even if you use 240 volts (though it is uncommon in the US), you won’t be able to use the full 48,000 watts.
Based on the 80% rule, you could use only 44,600 watts.
So, it is very important to know the electrical current capacity of your house while determining the power consumption.
Using appliances that the 200 amp electrical service panel can easily handle would be best.
Before you add appliances, you should know how much power you will get from 200 amps and how much power the appliances consume, especially heavy-duty ones like HVAC systems, refrigerators, and dryers.
A 200 amp service will be fine for a house measuring 2,000 or above square feet.
A 100 amp service is enough for a 3,00 square feet house, provided it does not contain any central heating system.
On the contrary, buildings with heavy machinery, like bigger HVAC systems, detached structures, or an elevator, will need a 400 amp service.
Based on the power consumption, you can easily run the following things with a 200 amp service:
- Household appliances like washing machines, dryers, dishwashers, and refrigerators.
- Electronic computers, laptops, tablets, and phones.
- Lighting systems.
- Heating and cooling systems.
- Large and small tools like sanders, circular saws, jigsaws, and table saws.
The 200 amp panel will easily handle these appliances.
Here is a list of some appliances’ power consumption amounts:
- Electric stove – 50 amps or 12,000 watts
- Lights and tamper-resistant outlets in a few rooms – 45 to 60 amps or 4,950 to 6,000 watts
- Dryers – 30 amps or 7,200 watts
- 3-ton electric heat pumps – 65 amps or 15,600 watts
- Electric range – 50 amps or 12,000 watts
- Air conditioner and electric furnace – 35 amps or 8,400 watts
- Electric tank water heater – 30 amps or 7,200 watts
However, residential houses will hardly draw such a high amount of current.
Heavy-duty appliances and electronic devices sometimes draw less than 80% of the amperage rating.
Relationship between amps, volts, and watts in the electrical circuit
To find out the wattage of the 200 amps and how much it can handle, you should understand the relationship between the amperage, volt, and wattage.
We need to divide the wattage by volt to determine the amperage rating.
The relationship between these three units is the essential relation in electricity.
The relationship is called Ohm’s law, which says that the voltage equals current multiplied by resistance.
Resistance is constant, and the ratio calculates the voltage and current.n
The voltage multiplied by the current equals the power. The formula is:
P (power) = V (volt) x I (power)
If the voltage increases, the power will also increase.
If you have a circuit of 120 volts and 10 amp current, you have a power output of 1,200 watts.
If the current increases to 20 amps, the power will be 2,400 watts.
However, volt-ampere is not equal to watt. Though both are the power units, W is the real power equal to the voltage product and current.
The volt-ampere or VA is the amount of apparent power consumed.
It is equivalent to the voltage product and current multiplied by the power factor.
Additionally, in a direct current, W = VA and W≤ VA in the alternating current.
Knowing the right amps and their capacity is something you should know without fail.
It will allow you to understand how to distribute the power evenly throughout your house.
You should contact a professional while installing the service panel and ask them about the panel’s wattage so that you can add appliances accordingly.
What is the 80% rule?
Whatever service panel you use, make sure to use it up to 80%, and leave the 20% free to prevent overload and short circuits. With 200 amps, you should use 160 amps at the most.
What does the NEC recommend about the electric panel capacity?
According to the National Electric Code, or NEC, the minimum electric panel for a house should be 100 amps.