NEC & IECC Content is current as of  January 8th 2013


We understand that in the normal course of approval of the permit application process for the installation of a radiant heated driveway, walkway or balcony, some inspectors may not have had the opportunity for first hand review of the relevant passages of the NEC and/or the IECC directly relating to outdoor permanently fixed radiant heating cables.

As well it would stand to reason that you may not have reviewed the OEM required specifications or the application of the NEC / IECC codes in direct relation to the installation of a permanently installed outdoor radiant heated driveway, walkway or balcony.

We hope the following is helpful for use as a reference resource regarding the installation of radiant heated driveways, walkways and balconies per the NEC and the IECC respectively.

For your review please find the relevant sections of the NEC:

The 2011 NFPA 70 / NEC Page 304, 305, 306 Articles 426 426.1 through 426.14 and 426.20 through 426.21D

Per the NEC, for the purposes of the permit application before you, the proposed system is a resistance heating system and not an impedence heating system. 

Should you have a recommendation for this section to help other inspectors or should you find / or know of another relevant section of the NEC or IECC that we should list please email us.  We will review your suggestion and add it as soon as reviewed.  For ourselves and on behalf of our clients we thank you for your time and consideration.

Article 426

Section 426.2 is not applicable.  This is a non skin effecting heating system.

Section 426.3 is applicable under this is a resistance heating only system.

Section 426.4 is applicable (continuous load).

Section 426.10 is applicable part ( 2 ) installation shall be per the OEM.

Section 426.11 is applicable and shall be embedded per the OEM.

Section 426.12 is applicable.  All radiant cables are embedded.

Section 426.13 is applicable.  A marker plate is embedded with the aggregate.

Section 426.14 is not applicable.

Article 426.20

(A) is applicable. 200 watts per square foot max.

(B) is applicable. OEM minimum is 3" on center.

(C) is applicable.  Radiant cable is installed 2" below surfaces.

(D) is applicable.  Radiant cable is attached by mechanical means of either Hilti or tied to 6" x 6" steel mesh.

Article 426.21

No radiant cable portion of the system is above ground.

Article 426.24 ( A ) ( B ) are applicable.

Article 426.25 is applicable.

Article 426.28 is applicable.  GFEP and EGFEP is used to comply.

Article 426.50 is applicable and is the preferred means for installation.

Article 426.51 ( A ) ( B ) ( C ) ( D ) are applicable and is the preferred means of installation - also see IECC page 32 Section 403.8

Article 427 is not applicable under any section as no portion of this system is exposed for possible personal injury.

2009 IECC

For your review please find the relevant sections and page number(s) of the IECC:

The 2009 IECC has been amended to the following: 

Page 32 - Section 403.8 Snow Melt system controls (Mandatory) 

Snow and Ice melting systems, supplied through energy service to the building, shall include automatic controls capable of shutting off the system when the pavement temperature is above 50 degrees and no precipitation is falling and an automatic or manual control that will allow shutoff when the temperature is above 40 degrees.

Certificate of listings for UL:

Certificate of listing for CSA:


GFEP or EGFEP Integration:

GFEP / GEFP / EGFEP Shall be integrated into the control portion of the project.

The integrated 30ma Ground Fault Equipment Protection shall provide a positive means of disconnect when the 30ma threshold is met.

Manner in which the radiant cable may be installed and the approved method for that process.


The radiant cable is installed between or below the asphalt at a minimum depth of 2" from the surface

The radiant cables can be slot cut and sealed within the slot or may be attached to the binder course and topped with a wearing course per the OEM


The radiant cable shall be installed beneath pavers and within a sand base a minimum of 2" from the surface.

The radiant cables are attached to a steel mesh grid and covered with applicable mason sand and covered per the OEM design.


The radiant cables shall be installed within a cement base a mimimum of 2" from the surface and attached to the wire mesh per the OEM


The radiant cables shall be installed within a 1" mortar base below the bluestone surface.

Installed below the 2" minimum from surface complies with the NEC and the OEM respectively.

Outdoor Tile:

The radiant cables shall be installed 1.5" from the surface when installed under outdoor tiling per the OEM.

Tar and Chip:

The radiant cables shall be installed a minimum of 2" from the surface when installed under a tar and chip surface per the OEM and the NEC.

Generac installations  

Clearances Per NFPA 37 and NFPA 37 Section 4.1.4

Please see the clearances sheets below for reference


Clearance updates as of 11/23/2011

Should You Have any Questions please call our offices at 973-728-5745  Monday Through Friday 9-5

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