Okay, let's break down this scenario and address your questions regarding wiring for your gasoline dispenser under a shed.

Understanding Hazardous Locations (NEC Article 514)



Key Concepts

Article 514 of the National Electrical Code (NEC) deals with gasoline dispensing and service stations. The core principle is to minimize the risk of ignition of flammable vapors. This is achieved by classifying areas as hazardous locations (Class I, Division 1 or 2) based on the likelihood of flammable vapors being present.

Figure 514.3(B)

This figure is crucial. It depicts the extent of hazardous (classified) locations around gasoline dispensers. As you correctly noted, the Division 2 area, according to the illustration, extends outward and downward, but does not typically extend above the dispenser.

Analyzing Your Specific Situation


Above the Dispenser



Assuming Proper Venting/Design

If the shed has adequate ventilation and is designed such that flammable vapors are unlikely to accumulate above the dispenser, then the area above the dispenser is generally considered non-hazardous.

Caveat - Special Circumstances

The crucial caveat is whether there are specific conditions that could lead to the accumulation of vapors above. For example:

Poor Ventilation

If the shed, despite lacking walls, has features that inhibit air circulation above the dispenser (e.g., a very low roof, close-fitting solid roof panels), then you might need to extend the hazardous location upward. This is a judgment call that should be made considering the specific layout.

Dispenser Design

Some older dispenser designs might vent in a way that could potentially release vapors upward.2.

Wiring Methods Above the Dispenser



General Wiring Methods Permitted (Usually)

If the area above the dispenser is, in fact, determined to be non-hazardous (due to adequate ventilation and dispenser design), then you can use general-purpose wiring methods as per the NEC. This would typically include:

Wiring in Conduit (EMT, Rigid Metal Conduit, PVC)

This is a common and robust choice.

Properly Rated Cable (e.g., THHN/THWN in conduit, or MC Cable)

The cable must be rated for the environment (temperature, moisture).3.

Flexible Cable to Receptacle



Issues to Consider

Your plan to use flexible cable (from the shed roof to a receptacle 30' away) introduces a few potential issues:

Mechanical Protection

The flexible cable needs to be adequately protected from physical damage. Running it exposed across that distance could be problematic. Consider running it inside conduit for a significant portion of the run, especially where it's likely to be bumped, tripped over, or exposed to weather.

Support

The cable needs to be properly supported at regular intervals to prevent strain on the connections and to keep it from sagging excessively.

Strain Relief

Proper strain relief is critical where the flexible cable connects to the dispenser and the receptacle. This prevents tension on the conductors within the cable. Use appropriate fittings.

Outdoor Rating

The flexible cable and the receptacle must be rated for outdoor use (wet location). Look for ratings like "WA" or "Wet Location Rated."

Ampacity

The flexible cable must have sufficient ampacity to handle the load of the dispenser motor. Use a conductor size appropriate for the current draw, with consideration for voltage drop over the 30-foot run.

GFCI Protection

The receptacle you intend to plug into must be GFCI protected. This is a requirement for outdoor receptacles.

Cord-and-Plug Connection

The cord-and-plug connection should only be used if the equipment is portable or needs to be easily disconnected for maintenance. A permanent wired connection is better if possible.

Important Considerations and Recommendations


Local Authority Having Jurisdiction (AHJ)

The most crucial step is to consult with your local electrical inspector (AHJ). They have the final say on whether the area above the dispenser is considered hazardous and what wiring methods are acceptable. They can also clarify any local codes or interpretations that might apply.2.

Professional Electrician

Engage a qualified and licensed electrician who is familiar with NEC Article 514. They can assess the site, ensure proper wiring methods, and obtain the necessary permits. This is especially important due to the inherent hazards associated with gasoline.
3.

Grounding

Ensure proper grounding of the dispenser and all associated electrical equipment. This is essential for safety.4.

Signage

Consider placing signage indicating the presence of a gasoline storage tank and the hazardous nature of the area.5.

Overcurrent Protection

Ensure the circuit breaker protecting the generator and the receptacle is appropriately sized for the dispenser load.

In summary: While the area above the dispenser may* be considered non-hazardous, it is critically important to have it verified by your local AHJ and a qualified electrician. They will assess the specific conditions of your installation and ensure compliance with all applicable codes and regulations. Your plan to use flexible cable requires careful attention to mechanical protection, support, strain relief, ampacity, and outdoor rating. Ignoring these factors could create a significant safety hazard. Flag for review