Been trying to study the Arc Flash formula(s) to determine the Flash zone.
All the formulas I've seen have a ( t ) for time, in seconds, for the OCPD to open the circuit.
What is the formula for when the Utility Company Primary OCPD of a large ( KVA ) transformer with a low Percent Impedance ( %Z ) and the Secondary side supplies a MLO panelbaord and a short circuit occurs on the line side of any OCPD with-in the MLO panelboard.
Would the time be the ' time it takes for the Secondary conductor ( Service Entrance cables , be they Service Drops or Service Laterals ) to melt into ?
If that is the case, what is the melting time, per conductor size, for either copper or aluminum service conductors ?
What about formulas for paralleled service conductors melting ?
All the formulas I've seen have a ( t ) for time, in seconds, for the OCPD to open the circuit.
What is the formula for when the Utility Company Primary OCPD of a large ( KVA ) transformer with a low Percent Impedance ( %Z ) and the Secondary side supplies a MLO panelbaord and a short circuit occurs on the line side of any OCPD with-in the MLO panelboard.
Would the time be the ' time it takes for the Secondary conductor ( Service Entrance cables , be they Service Drops or Service Laterals ) to melt into ?
If that is the case, what is the melting time, per conductor size, for either copper or aluminum service conductors ?
What about formulas for paralleled service conductors melting ?