Installation Guide

Planning the Installation
SECTION 3
5
3.4 Calculation of On-Center Spacing (OC)
InordertottheTempZone™FloorHeatingCableproperlyinthedesignatedspace,itisnecessarytodeterminethe
spacingbetweenthecables.Thisiscalledon-centerspacingorOC.Refertoeitherthe“ProductSelectionGuide--120V”or
“ProductSelectionGuide--240V”insection9todetermineappropriatespacingfortheinstallation.
Combinecablelengthsifmorethanoneisneededfortheinstallation.OncetheOCspacinghasbeencalculatedandthe
correctlengthofcablefortheareatobeheatedisobtained,installationoftheoorheatingcablecanbegin.Theformula
assumesthat3-inchspacingwillbeusedbetweentheheatingcableandwallsorxedobjects,andfullOCspacing
betweencableruns.Tomakecableplacementeasier,makeameasuringtemplateoutofcardboardinthewidthoftheOC
spacinglessthethicknessofthecable.Placethetemplatealongtothecablerunjustcompletedtodeterminewherethe
nextrunofcableshouldbepositioned.
IMPORTANT: To avoid overheating, OC spacing should not be less than 3 inches and area loading should not
exceed 15 watts/square foot.
IMPORTANT: Do not order more cable than necessary as cable cannot be shortened.
3.7W Cable vs 3W Cable Wattage Yields
Current
3 W Cable
New
3.7 W Cable
Membrane Type
(number of studs)
Watts/linear ft 3 3.7
Watts/ft2at2.5” 14.4 17.76* Prodeso(2)
Watts/ft2at3” 12 14.8 CableFixingStrip(3)
Watts/ft2at3.5” 10.3 12.7 DITRA-HEAT(2)
Watts/ft2at3.75” 9.6 11.84 Prodeso(3)
Watts/ft2at4” 8.7 11.1 CableFixingStrip(4)
Watts/ft2at4.75” 7.6 9.3 DITRA-HEAT(3)
Watts/ft2at5” 7.2 8.9 CableFixingStrip(5)&Prodeso(4)
Wire diameter variable 4.37
DITRA-HEAT:1.75”
Prodesospacing:1.25”
Strips:1”
*Notrecommendedasitexceedsthe15wattpersquarefootlimitsetbytheNationalElectricCode.