**Contents**show

## How do you determine breaker size?

To calculate the breaker size, simply **divide the adjusted wattage by 240 volts to find the rated amperage needed for your subpanel**. Often, the result is not a common circuit breaker size. and you can simply round up to the next higher size of the breaker.

## Why do we use 1.73 for three phase?

In a three phase circuit, the use of the constant 1.732 results from **the fact that not all three phases are producing the same amount of power at the same time**. … Suffice it to say that the correct power from a three-phase system at any point in time is found by multiplying by the square root of 3.

## What is the standard circuit breaker size?

The standard for most household circuits are rated either **15 amps or 20 amps**. An important note to remember is that circuit breakers can only handle about 80% of their overall amperage. That means a 15-amp circuit breaker can handle around 12-amps and a 20-amp circuit breaker can handle about 16 amps.

## Does a 200 amp 3 phase service equal a total of 600 amps?

Originally Answered: Does a 200 amp 3 phase service equal a total of 600 amps? **No**, because each one of the three phase wires is supplying amperage for only one third of the time. The power rotates very fast between those three wires, 60 times per second, so that enables the wires to be much smaller than normal.

## How do you find the phase current?

Phase current I_{(}_{P}_{)} in **Amps is equal to line current I _{(}_{L}_{)} in Amps divided by root 3**. Example: Calculate the phase current of the delta connected alternator output line current of 1500 Amps. I

_{(}

_{P}

_{)}= 1500 / 1.732 = 866 Amps.

## How do you calculate amps in a 3-phase circuit?

Divide the power consumption in watts by the line voltage multiplied by the power factor to find the amperage. For three phase circuits the power factor is **the square root of 3**. If your calculator doesn’t have a square root function, use 1.73 as an approximation of the square root of 3.

## What does 1.73 mean in electrical calculations?

The ratio between the leg length of the “Y”, and the leg length of the equilateral triangle, will be the square root of 3, which is approximately 1.732. This is **the ratio between line-neutral voltage and line-line voltage**, in a three phase system.

## How is 3-phase voltage and current measured?

Read and record the phase to phase voltage between phase 2 and 3. Average **all three legs by adding the total sum voltage of all three legs and divide by three** to find the operating voltage. Record the phase to phase voltage. Verify all three-phase to phase voltages are within 3% of the same voltage.

## Is 240V 3-phase the same as 208V 3-phase?

**208V is *not* the same as 240V**. 208V is the voltage between phases of a 3-phase “Y” circuit that is 120V from neutral to any hot. 480V is the voltage between phases of a 3-phase “Y” circuit that’s 277V from hot to neutral.