You're right to question the plan checker's interpretation. Let's break down why, referencing the NEC (National Electrical Code), which is the standard in most jurisdictions.

NEC Definitions and Considerations Wet Location (NEC Article 100)

"Installations under ground or in concrete slabs or masonry in direct contact with the earth; in locations subject to saturation with water or other liquids, such as vehicle washing areas; and in unprotected locations exposed to weather."

Damp Location (NEC Article 100)

"Locations protected from weather and not subject to saturation with water or other liquids but subject to moderate degrees of moisture."

Dry Location (NEC Article 100)

"A location not normally subject to dampness or wetness. A location classified as dry may be temporarily subject to dampness or wetness, as in the case of a building under construction."

Why the Plan Checker's Interpretation is Likely Incorrect Proximity Doesn't Equal Saturation

Simply being near a mop sink or water heater does not automatically make a location "wet." The key is whether the location is subject to saturation with water or other liquids. A typical mop sink area or water heater area isn't normally saturated with water. Occasional splashes or leaks, while possible, don't meet the threshold of being a wet location.

Likely a Damp Location at Most

If anything, the location might be considered a damp location, depending on the ventilation and how frequently water splashes might occur. However, even that might be a stretch.

Intent of Wet Location Requirements

The NEC's intent for wet location requirements (like NEMA 3R enclosures) is to protect electrical equipment from continuous or frequent exposure to water, like rain, direct splashing from a hose, or submersion.

Why NEMA 3R Might Be Overkill Cost and Availability

NEMA 3R panels are more expensive and may not be readily available, especially for smaller panel sizes.

Installation Considerations

NEMA 3R panels often require specific mounting techniques to maintain their weather-resistant rating.

What to Do Next1. Respectfully Challenge the Interpretation

Contact the plan checker and politely explain your understanding of the NEC definitions. Reference the definitions of wet, damp, and dry locations in Article 100 of the NEC.2.

Provide Justification

Explain why you believe the location is not subject to saturation. For example, you could state: "The panel is located three feet from the mop sink and one foot from the water heater, ensuring it is not directly exposed to splashing or water spray." "Normal operation of the mop sink and water heater will not result in the area around the electrical panel being saturated with water." "The area is indoors and protected from weather."3.

Offer Alternatives (if needed)

If the plan checker is still concerned, consider offering a compromise:

Damp Location Protection

If the plan checker insists on more protection, you could suggest using a NEMA 1 enclosure with appropriate drip shields above the panel or ensuring good ventilation in the area to prevent moisture buildup.

GFCI Protection

Emphasize that the circuit(s) feeding the panel will be GFCI protected as required by the NEC, providing an extra layer of safety in case of any accidental water exposure.4.

Escalation (if necessary)

If you can't resolve the issue with the plan checker, ask for a meeting with their supervisor or the head of the permitting department. Be prepared to present your case clearly and professionally.5.

Document Everything

Keep a record of all communication with the plan checker, including dates, times, and the content of the conversations.

Key Points to Emphasize in Your Communication NEC Definition

Quote the NEC definitions of wet, damp, and dry locations.

Normal Operating Conditions

Focus on the normal operating conditions of the mop sink and water heater and why those conditions would not lead to saturation.

Code-Compliance: Reassure the plan checker that you are committed to code compliance and safety but that you believe the NEMA 3R requirement is not justified based on the specific location and intended use.By following these steps and presenting your case clearly and professionally, you have a good chance of resolving the issue and avoiding the unnecessary expense and complexity of a NEMA 3R panel. Good luck! Flag for review