You're right to be cautious and seek clarification on the "outdoors" requirement of NEC 2023 700.3(F)(6) regarding temporary generator connection points. The specific wording and intent of the code are critical here. While perforated metal panels suggest outdoor exposure, whether they satisfy the code's intent is what you need to determine.Here's a breakdown of the factors and a recommended course of action

Factors to Consider:
Code Intent

The primary reason for requiring the connection point to be outdoors is

ventilation and safety. Temporary generators, even when used temporarily, produce exhaust fumes, including carbon monoxide. Enclosed or partially enclosed spaces can allow dangerous levels of these fumes to accumulate. The code seeks to ensure safe operation by mandating an environment where exhaust dissipates readily. Definition of "Outdoors"

The NEC doesn't explicitly define "outdoors" in this context (or often at all!), which leads to interpretation. A common-sense interpretation would involve an area exposed to the elements and with sufficient natural ventilation to prevent dangerous fume buildup.

Perforated Metal Panel Facade

The effectiveness of perforated metal panels in providing adequate ventilation depends on several factors:

Percentage of Open Area

What percentage of the panel is open space? A high percentage is better.

Panel Design

How evenly are the perforations distributed?

Prevailing Winds

What is the typical wind direction and speed in that location? Will it naturally draw air through the garage?

Garage Configuration

Is the garage mostly open on other sides, or is it relatively enclosed? (A "tunnel effect" can be problematic.)

AHJ Interpretation

Ultimately, the Authority Having Jurisdiction (AHJ) has the final say in interpreting and enforcing the code. Their opinion is the one that matters most.

Why Your Situation is Questionable

While your proposed location is adjacent to the outdoors, a parking garage, even with perforated panels, is not the same as being fully outdoors. A parking garage is a structure that has certain building code requirements as well.

Recommended Course of Action


Consult with an Electrical Engineer

Before approaching the AHJ, discuss this with a licensed electrical engineer familiar with the NEC and local codes. They can evaluate the site, assess the ventilation characteristics of the proposed location, and provide a professional opinion on whether it meets the intent of the code. They can also offer alternative solutions if necessary.2.

Gather Information

Collect as much information as possible about the ventilation characteristics of the garage. This might include: Architectural drawings showing the layout of the garage and the location of the connection point. Specifications for the perforated metal panels, including the percentage of open area. Any existing ventilation calculations or studies for the garage. Wind rose data for the local area. Photographs of the location.3.

Submit a Formal Request for Interpretation to the AHJ (Recommended)

This is the best way to proceed. Prepare a well-documented request for interpretation that includes: A clear explanation of the situation and the proposed location of the connection point. The supporting information you gathered (architectural drawings, panel specifications, etc.). An explanation of why you believe the proposed location meets the intent of the code (i.e., that it provides adequate ventilation for exhaust fumes). Reference the relevant section of the NEC (700.3(F)(6)). Clearly state your question: "Does the proposed location, just outside the generator room on the second floor of the parking garage with a perforated metal panel facade, satisfy the 'outdoors' requirement of NEC 2023 700.3(F)(6)?"4.

Follow the AHJ's Guidance

The AHJ's decision is binding. If they approve your proposed location, get it in writing. If they reject it, be prepared to discuss alternative solutions that comply with the code.

Possible Alternative Solutions (If the AHJ Rejects Your Proposal)



Relocate the Connection Point

Move the connection point to a truly open outdoor location, even if it's less convenient. Consider the roof, a loading dock, or a dedicated outdoor enclosure.

Forced Ventilation

If relocating the connection point is not feasible, explore the possibility of installing a permanent forced ventilation system in the garage to ensure adequate exhaust removal when a temporary generator is connected. This would likely require engineering calculations and approval from the AHJ. You'd need to demonstrate that the system effectively removes fumes and prevents dangerous CO levels.

Consider Other Generator Types

Explore options of generators that may not need to exhaust gases in the same way. (This may not be a viable option).

Important Considerations



Carbon Monoxide Detectors

Regardless of the location of the connection point, it's always a good practice to install carbon monoxide detectors in the surrounding area to provide an early warning in case of exhaust fume buildup.

Generator Placement

Even with an "outdoor" connection, ensure that the temporary generator is positioned to minimize the risk of exhaust fumes entering the building. Direct the exhaust away from windows, doors, and air intakes.

Safety Procedures: Develop and implement clear safety procedures for connecting and operating temporary generators, including procedures for monitoring carbon monoxide levels.By taking a proactive and well-documented approach, you'll be in the best position to obtain approval for your proposed solution or to implement an acceptable alternative. Flag for review