Code Change Summary: A new definition of the term “Short Circuit” has been added to Article 100.

There are many words and terms in the NEC^® that the electrical industry is assumed to know whether they are defined in the code or not.

The NEC^® has a definition of a “Bathroom” for example. Most would think a bathroom is self-explanatory but, in the NEC^®, specific requirements apply to electrical installations in a bathroom that would not apply to a room that has only a toilet, without a sink.

One would hope that everyone in the electrical industry and beyond understands what an electrical short, or short circuit is without further explanation, but who knows.

A short circuit is a shunt connecting two parts of an electric current so as to carry a greater part of it.

The term “Short Circuit” appears many times throughout the NEC^® but without a definition, the Code reader must rely on other publications to determine the definition of this term.

In the 2023 NEC^®, a short-circuit is an abnormal connection or even an arc of relatively low impedance, whether made accidentally or intentionally, between two or more points of different potential. This new definition helps to further understand and differentiate between other terms used throughout the NEC^® such as:

• Fault Current. The current delivered at a point on the system during a short-circuit condition.
• Available Fault Current. The largest amount of current capable of being delivered at a point on the system during a short-circuit condition.
• Ground Fault. An unintentional, electrically conductive connection between an ungrounded conductor of an electrical circuit and the normally non-current-carrying conductors, metal enclosures, metal raceways, metal equipment, or earth.

A short circuit condition generates a higher amount of energy than a phase to ground (ground-fault) condition which is why the term “Available Fault Current” is based on a short circuit rather than a ground-fault.

When a short circuit occurs, two or more conductors, each having a difference in potential between them, are abnormally connected creating the short circuit condition.

Below is a preview of the NEC^®. See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2023 NEC^® edition of NFPA 70.