Bills Technical Journals

Technical Journal #1

Technical Journal #2

Technical Journal #3


Technical Journal #4

Technical Journal #5

Technical Journal #6

The game of professional football has some useful similarities to the administration of the National Electric Code (NEC) that can help better understand the role of the Authority Having Jurisdiction (AHJ).
For example, in the National Football League (NFL) the rules are set by the NFL and enforced during the playing of the games by Referees. Each Referee has the ability to interpret the rules and to enforce them during the game. A Referee can allow play to continue – or he can make a call during the game regarding whether a forward pass was caught for a completion, or dropped, and ruled an incomplete pass.
It can help to think of the AHJ as the Referee for the NEC. And the NEC “game” occurs during new construction, remodeling or other construction activity that involves electrical systems or components of the electrical system. The AHJ’s “rules of the game” are in the NEC, and they can call “penalties” during construction as they enforce the NEC.
The Coach of an NFL football team can appeal a Referee’s penalty call by throwing a red flag, and the Referee’s decision is reviewed and replayed on video tape by other NFL Referees. During this appeal process, the game stops, and waits for the review process to be completed. The on-field Referee’s decision can be reversed by this appeal process, or it can be left as originally called. The game only resumes after the review is completed.The same series of events can occur with the AHJ, who can issue a “penalty flag” that stops construction until the problem found is corrected and meets NEC standards. And while there is no video replay review with the AHJ, there is an appeal process that exists to challenge AHJ rulings. And like the game of football, the “game” of construction stops until the AHJ review is completed.Just as there are the rules of a football game, as written in the official Rule Book, there are the rules of the NEC. And the Referee and AHJ must apply these rules during their “games.” Neither the Referee nor the AHJ can create a new rule, but they do have the ability to decide and interpret the rules. Decisions regarding “Un-sportsman-like Conduct” and “Roughing the Passer” penalties may be called by the NFL Referees. Some penalties, like “Off-sides” are very clear and easy to determine, while others, like “Pass Interference” take judgement and an interpretation of “incidental or accidental contact” vs malicious and obviously intentional interference. NEC codes can involve the same judgement calls.In the game of football the Head Referee is responsible for the general supervision of the game and is in charge of stopping and starting the game. But there are other Referees that report to him on the field, each with their own specialty or part of the game to monitor. Each Referee has the power to call a penalty and stop the game.With the AHJ there can also be a “team” of Referees, each with their own specialty or zone of control. A small project can have a designated AHJ as the local Electrical Inspector from the County Building Dept.
Larger projects can include additional “Referees” on the team as additional AHJ Team members like the Fire Marshall, the County Health Dept. Rep, a city Planning Dept. Rep or the School Facilities Manager for schools. For insurance purposes an Insurance Inspector, Insurance Rating Bureau Chief or other Insurance Company Rep. may become AHJ’s on the Team as well.

Technical Journal #7

In NEC Article 500, 501, 502, and 503, Class I, II, and III locations are further broken down into Divisions. The simplified version of a Division for a given Class will be either:

Division 1: The ignitables are significantly present under normal conditions.

Division 2: The ignitables are significantly present under abnormal conditions.


A hazardous location in which ignitables are significantly present in the air in normal conditions in sufficient quantities to be explosive or ignitable, such as petroleum refineries, aircraft hangars, dry cleaning plants, utility gas plants or storage areas for liquefied petroleum or natural gas, and spray finishing areas.




A hazardous location in which ignitables are not normally present in in the air in sufficient quantities to be explosive or ignitable. For example: Closed storage drums containing flammable liquids in an inside storage room would not normally allow the hazardous vapors to escape into the atmosphere. But if one of the storage containers spills over and dumps liquid on the floor, or is old and leaking, you’ve got an abnormal condition.


Abnormal condition:









Spilled flammable liquid

Technical Journal #8

There can be two different types of catastrophic events in areas classified as hazardous locations. There can be Fires, which are purely chemical reactions that release heat during the combustion process.

And there can be Explosions, which release a large amount of energy in a very short period of time, often accompanied by a rapid expansion of volume.

Why is this important to the classification of Hazardous Locations?

The temperature where a material burns is important to know, and a scale can be created of the relative flammability of different materials.

There are many different materials, vapors and gases that create other different types of risk for a building. These materials are categorized based on the potential risk they pose for the creation of an explosion – and they are also categorized as to how big or how violent an explosion that can result, IF they exploded.

And, YES – there are different types of explosions, and the extremes might be imagined as a July 4th fire-cracker at one end of the spectrum, and an atomic bomb being at the other end.

Fires and Explosions have rating systems, and these two phenomena are related in a way – Fires can also result from explosions, and explosions can result from fires.

The major distinction between Fire and Explosion is the rate of energy release. Fire releases energy relatively slowly when compared to explosions, which release energy rapidly, typically in thousandths of a second (microseconds).


But the key difference is the rate of the release of energy. For example, compressed air within a balloon contains energy. If the energy is released slowly through the balloon air stem, the balloon is harmlessly deflated – but if the balloon pops suddenly and all the energy within the compressed balloon releases at once, the result becomes a small explosion.

And taking all of this back to the world of Hazardous Location classifications, realize that this is how the “Groups” of materials, vapors and gases are created. There will be more covered on different types of “Groups” later – in future Journals, but the important point here is that “Groups” are created based on:

1.)  Their flammability and
2.)  The severity of the explosion they can create.