An example of a high-impedance grounded neutral system

[JJWalecka]

Could someone give me an example of a High-Impedance grounded neutral system. I'm not familiar with the term.
Article 250.36 (A) Grounding Impedance Location. The grounding impedance shall be installed between the grounding electrode conductor and the system neural. Where a neutral is not available, the grounding impedance shall be installed between the grounding electrode conductor and the neutral derived from a grounding transformer.

What does the code mean by grounding impedance?
What is a grounding transformer?
American Electricians Handbook defines Impedance as the name given to the total opposition to the flow of alternating current. It is the combined opposition of resistance, inductive resistance, and capacitive reactance. Impedance is measured in ohms and is expressed by the symbol Z.

 

[tom baker]

Re: An example of a high-impedance grounded neutral system

Here is a document with more information. This type system is commonly used in industrial locations. It offers the advantages of a solidly grounded system and an ungrounded system.
http://www.ipc-resistors.com/pdf/IPCSTOPLIGHT.pdf

 

[JJWalecka]

Re: An example of a high-impedance grounded neutral system

Thank you Tom Baker. Unfortunately I do not have enough space for the application.

Justin

 

[Ed MacLaren]

Re: An example of a high-impedance grounded neutral system

In most systems, the resistor (or reactor) value is such that a bolted ground fault will result in a fault current of not more than 5 to 10 amps.

This will not open a OCPD, and, as long as the first ground fault is located and repaired before another ocurrs, a power interruption is prevented, and an orderly shut-down of critical operations is permited.

Ed

 

[JJWalecka]

Re: An example of a high-impedance grounded neutral system

Thank you Ed MacLaren.

Justin