Fact check: What specific article in national electrical code will allow floor heat in a residential bathroom to be installed on a dedicated 120 volt 20 amp individual circuit for one bathroom?

1. Summary of the results

Based on the analyses provided, there are two key NEC articles that address the question about floor heating in residential bathrooms:

Article 210.11(C)^[1] allows a single 20-amp branch circuit to feed all bathroom receptacles if the circuit is dedicated to only one bathroom, which means floor heat could potentially be installed on the same 120-volt 20-amp circuit for a single bathroom ^[2].

Article 424, specifically Part V on Electric Space-Heating Cables, governs floor heating cable systems and includes important requirements such as GFCI protection under Article 424.45(E) ^[3]. For a 120-volt, 20-amp under-tile system, manufacturers typically recommend not exceeding 16 amps on a 20-amp circuit and using a #12 conductor ^[3].

However, several sources failed to provide specific NEC article references despite discussing bathroom electrical requirements and floor heating installations ^{[4] [5] [6]}.

2. Missing context/alternative viewpoints

The original question lacks several critical safety and installation considerations:

• GFCI protection requirements - Article 424.45(E) mandates GFCI protection for floor heating systems, which is essential for bathroom safety ^[3]
• Load limitations - Even on a 20-amp circuit, manufacturers recommend not exceeding 16 amps for floor heating systems to ensure safe operation ^[3]
• Conductor sizing - Proper wire gauge (#12 conductor) is required for 20-amp circuits ^[3]
• Multiple circuit requirements - Bathrooms typically require at least two dedicated circuits: one 20-amp receptacle circuit and another for lighting/exhaust fan, which could affect the floor heating installation approach ^[6]

Electrical contractors and floor heating manufacturers would benefit from promoting simpler installation approaches that appear to require fewer circuits, as this could reduce installation costs and complexity for customers.

3. Potential misinformation/bias in the original statement

The original question contains no apparent misinformation but demonstrates an incomplete understanding of the electrical code requirements. The question focuses solely on finding a single article that "allows" the installation without considering:

• The mandatory safety requirements that must be met regardless of which article permits the installation
• The practical limitations on circuit loading that may make a shared circuit approach inadvisable
• The manufacturer specifications that often impose stricter requirements than the minimum code standards

The framing suggests the questioner may be seeking the simplest possible interpretation of the code rather than a comprehensive understanding of safe installation practices. This approach could lead to installations that meet minimum code requirements but fall short of optimal safety and performance standards.