What is prospective short circuit test?
The Prospective Short Circuit Current(PSC) is the utmost current that could flow between Line and Neutral conductors on a single-phase supply or between Line conductors on a three-phase supply. A PSC test calculates the current that will flow in the event of a short circuit fault between the live conductors.
Why do we measure prospective fault current?
A PFC test calculates the current that will flow in the event of an earth fault; i.e., Line to Earth. It is important that we conduct the tests to make sure that the protective devices installed within a circuit are rated at the correct breaking capacity.
How do you calculate PSC?
The PSC can be determined by measurement or by calculation. Many multi-function testers are able to measure the PSC. PSC can also be calculated by undertaking a Live Fault Loop Impedance measurement (in ohms) and dividing the voltage by this measurement.
What is the difference between PSC and PFC?
PSC will be higher than the PFC. Prospective fault current and short circuit current of a circuit is automatically calculated when making a loop impedance test. The calculation uses a nominal circuit voltage, not the actual circuit voltage.
Can you calculate Pfc from Ze?
To calculate PFC from Ze or Zs enter your voltage and Ze / Zs values and hit “Calculate”, the single phase and three phase PFC results will be displayed. This PFC Calculator is extremely easy to use, just enter any two values and hit “Calculate” to calculate the other.
What is a normal prospective fault current?
The Prospective Earth Fault Current is the maximum current that could flow between Live conductors and Earth. The higher of these two values will be noted down as the Prospective Fault Current (PFC).
How do you calculate prospective short circuit current in single phase?
In this case, the PSC can be calculated by multiplying the single phase reading by the square root of 3 or 1.73. Therefore in the example above, the PSC would be 3000 x 1.73 = 5190 A or 5.19kA.
What is the maximum prospective fault current?
The maximum prospective fault current is the higher of the two fault currents (line-to-neutral or line-to-earth) and should be recorded on the certificate or report, as part of the details of the supply characteristics.
How do you calculate prospective fault current in a single phase?
What is an acceptable prospective fault current?
In such circumstances, the maximum prospective fault current should be recorded as 16 kA in the relevant part of the electrical certificate or report, and undertaking prospective fault current testing at any point in the installation would be considered unnecessary.