mbrooke
Batteries Included
- Location
- United States
- Occupation
- Technician
In terms of the series impedance of a wire or cable run rather than a transmission line, it does in fact not make a difference, as the poster I replied to stated.
Right, but the quote said the ground wire would not carry current. Ground faults are by far the most important considering:
1) breaker must open fast enough to prevent electrocution. (0.4 seconds for 277/480, 0.8 seconds max for 120/208)
2) Ground wire must not overheat or melt
3) Its wise to reduce incident energy at the fault point.
These 3 are governed by the combined impedance of the phase and ground wires. With a low enough impedance all 3 are successfully covered.
Where as excessive voltage drop at a device is typically not a hazard.