Prospective fault current
- Thread starter Jacobssi
- Start date
- Status
Sponsored Links
The amount of current that would flow until operation of the protective device.
This could be due to a direct short between L and N, or L and E, or phase to phase on a three phase install.
The fault current would be determined by the loop impedance of the fault and the supply voltage, for example, if your Ze at the origin is 0.15ohms, your prospective fault current would be 230 devided by 0.15 which equals 1533amps (1.53kA). Some beginners tend to assume that because the main fuse is 80 or 100amps that the current that will flow during a fault will be limited to this - it wont be. Thousands of amps will flow until the protection operates (which is typically in a fraction of second).
The PFC would decrease the further down the circuit or installation you go due to the loop impedance increasing.
This could be due to a direct short between L and N, or L and E, or phase to phase on a three phase install.
The fault current would be determined by the loop impedance of the fault and the supply voltage, for example, if your Ze at the origin is 0.15ohms, your prospective fault current would be 230 devided by 0.15 which equals 1533amps (1.53kA). Some beginners tend to assume that because the main fuse is 80 or 100amps that the current that will flow during a fault will be limited to this - it wont be. Thousands of amps will flow until the protection operates (which is typically in a fraction of second).
The PFC would decrease the further down the circuit or installation you go due to the loop impedance increasing.
This is a duplicated topic.
DIYnot Local
Staff member
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local
- Status
Sponsored Links
