Ground Fault Path to sourcer

[dbrooks1027]

If an ungrounded conductor makes contact with the metal case of an enclosure, lets say a 120 volt circuit and the equipment grounding conductor is .5 ohm that would make it a 240 amp ground fault back to the source. My question is, isn't it dangerous for 240 amps to be live on all the metal raceways, enclosures on its way to the source? Even if the circuit breaker trips quickly, in that split second it takes to trip wouldn't it still zap you if you were leaning or touching any metal?

Thanks in advance

 

[iwire]

If an ungrounded conductor makes contact with the metal case of an enclosure, lets say a 120 volt circuit and the equipment grounding conductor is .5 ohm that would make it a 240 amp ground fault back to the source. My question is, isn't it dangerous for 240 amps to be live on all the metal raceways, enclosures on its way to the source? Even if the circuit breaker trips quickly, in that split second it takes to trip wouldn't it still zap you if you were leaning or touching any metal?

Welcome to the forum.

You are correct, you could get a shock in the time it takes the breaker to trip.

Do you have a solution to this issue?

By the way, you forgot the circuit conductor impedance in your figure but I understood what you where getting at.

 

[electrofelon]

If an ungrounded conductor makes contact with the metal case of an enclosure, lets say a 120 volt circuit and the equipment grounding conductor is .5 ohm that would make it a 240 amp ground fault back to the source. My question is, isn't it dangerous for 240 amps to be live on all the metal raceways, enclosures on its way to the source? Even if the circuit breaker trips quickly, in that split second it takes to trip wouldn't it still zap you if you were leaning or touching any metal?

Thanks in advance

There does not seem to be a perfect electric system: grounded, ungrounded, impedance grounded. Each has advantages and disadvantages. With a grounded system, you are basically making all the metal stuff a circuit conductor (but most of the time only under fault conditions) which can expose us to potential differences under several circumstances. Ungrounded systems may seem like they would be vastly superior at first, but then we have that pesky capacitance, and assuring that a first fault is detected and corrected promptly can be challenging.

As to your specific question, Note that one would have to be in contact with a grounded object to receive a shock during the fault, and considering shoes, non conductive flooring, etc, its not super likely.