King Electric FC12120, FC12300, FC12180, FC12240, FC12360 Installation Manual

cable

series

Electric Floor Heating Cable Systems

INSTALLATION

This installation manual includes factory guidelines for installing King Electric floor heating systems.
These guidelines must be followed to ensure warranty coverage. Contact King Electric for any questions
regarding proper installation of the heating cable.

IMPORTANT: Save these instructions!

800-603-5464

MANUAL

king-electric.com

Electric Floor Heating Cable Systems

www.king-electric.com

Table of Contents

1. General Information ------------------------------------------------------------------------------ 3

2. Typical Installations ------------------------------------------------------------------------------- 3

3. Important Safeguards and Warnings ------------------------------------------------------------------ 4

4. STEP 1: Inspect and Testing the Cable and Floor Sensor ---------------------------- 5

5. Cable Test Log --------------------------------------------------------------------------------------------------- 6

6. STEP 2: Layout Planning and Product Selection ----------------------------------------- 7

7. 120 Volt Selection Table -------------------------------------------------------------------------- 8

8. 240 Volt Selection Table --------------------------------------------------------------------------- 9

9. STEP 3: Thermostat Location and Strapping Layout ----------------------------------- 9

10. Materials Required ------------------------------------------------------------------------------- 11

11. STEP 4: Electrical Rough-in New Construction ----------------------------------------- 12

12. STEP 4: Electrical Rough-in for Remodel ------------------------------------------------- 13

13. STEP 5: Transfer Layout to Floor and Plan Cable Routing -------------------------- 14

14. STEP 6: Installing the Metal Strapping ------------------------------------------------------ 14

15. STEP 7: Installing the Cold Lead ------------------------------------------------------------ 16

16. STEP 8: Lace the Cable Through the Strapping ----------------------------------------- 17

17. STEP 9: Install the Floor Sensor ------------------------------------------------------------ 18

18. STEP 10: Apply Scratch Coat ---------------------------------------------------------------- 18

19. STEP 11: Install the Thermostat --------------------------------------------------------------- 19

King Electrical Floor Heating Cable Installation Manual

2

General information

Electric floor heating is a simple, economical way to warm any floor providing years of lasting
comfort whether it is used as supplemental or the primary heating source. This installation
manual provides guidelines, safety warnings and describes the elements of properly installing
the King Electric floor heating system which are:

1. How to design the proper layout for the room.

2. How to select the right product for the application.

3. How to properly install the system.

This installation manual DOES NOT provide detailed information regarding thermostat installation.
It is important to thoroughly review the thermostat installation manual included with the
thermostat. For additional information regarding any aspect of the King Electric floor heating
system, please contact us at:

King Electrical Manufacturing Co..
9131 10th Ave South
Seattle, WA 98108

1-800-603-5464
www.king-electric.com

Tiles, Stone

Scratch coat
(optional)

Directly on plywood

Standard spacing = 3 inches

Typical Installations

Thin-set

Backerboard
(optional)

Plywood subfloor

Tiles, Stone

Scratch coat
(optional)

Directly on concrete

Insulated slab spacing = 3 inches
Un-insulated slab spacing = 2 inches

Thin-set

Insulation
(optional)

Concrete slab

King Electrical Floor Heating Cable Installation Manual

3

Important Safeguards and Warnings

READ AND FOLLOW THE WARNINGS AND INSTALLATION INSTRUCTIONS PROVIDED IN THIS MANUAL.
FAILURE TO DO SO COULD RESULT IN ANY OF THE FOLLOWING: CABLE FAILURE, IMPROPER SYSTEM
OPERATION, PROPERTY DAMAGE, BODILY INJURY OR DEATH. THE WARRANTY IS INVALID IF THE
WARNINGS AND SPECIFIC INSTRUCTIONS ARE NOT FOLLOWED.

WARNING: ELECTRIC SHOCK AND FIRE HAZARD!

1. The instruction manual follows North American standard building construction conventions.

2. An electrical inspector may be required before, during and after the installation. It is recommended to
contact your local building department BEFORE beginning the installation.

3. DO NOT energize the cable before installation as it will cause overheating or damage to the cable.

4. Connect cables to rated voltage only. Be sure to size for conductors properly to carry the rated amperage.

5. This product is approved for indoor use only. Minimum installation temperature is 40 F .

6. Use only copper supply wires. Be sure to size for conductors properly to carry the rated amperage.

7. DO NOT cut the blue heating cable or attempt to alter the length in any way. The black cold lead can
be shortened, but only at the end of the cable where the power leads are exposed. DO NOT cut at the splice
between the cold lead (black wire) and the heating wire. (blue wire)

8. DO NOT install heating cable under any type of floor that requires nailing.

9. Ground fault protection (GFCI) is required when installed in wet environments such as a bathroom. Consult the
local electrical and building authority to determine and additional requirements in your area.

10. If the GFCI trips during normal conditions and cannot be reset, consult an electrician for service. NEVER
attempt to bypass or disable the GFCI system.

11. When installing cable in shower areas, the cable must be installed under the waterproofing membrane to
keep the cables dry.

12. DO NOT drill, nail of cut into any floors that have heating cable installed underneath. This could result in
contact with live electrical wires causing electrical shock.

13. DO NOT use staples, nails or similar fasteners directly on the cable. Use only factory the factory strapping
system to attach cable. The use of any other fastening method will void the warranty.

14. Use a smooth plastic trowel only. NEVER bang or drop a tool on the cable. Care should be taken not to
nick or gouge cable.

15. DO NOT install the heating cable under a cabinet or other built-in. This will cause the cable to overheat.

16. DO NOT install the heating cable (blue wire) inside a wall. Only the cold lead can go into a wall stud.

17. DO NOT extend the heating cable beyond the room or area that it originates.

18. DO NOT attempt to repair damaged cable without a factory splice kit.

19. DO NOT overlap heating cables. Dangerous overheating will occur.

20. DO NOT allow the cold lead or thermostat sensor to cross or overlap the heating cable.

21. All cables must be completely embedded into a cement based mortar including the cold lead, cold lead
splice, heating cable, heating cable tail splice and thermostat sensor with the wire lead.

22. DO NOT bend the cable at sharp right angles. Always maintain a minimum 1” radius.

23. Maintain at least a minimum of 2” between heating cables.

24. Test and record the cable resistance at least 4 times during installation.

25. After installation of the cable, the installer must inspect and remove damaged or defective cables
before they are covered or concealed.

26. The installer should mark the appropriate circuit breaker reference label indicating which branch circuit
supplies the circuits to those electric space heating cables.

27. These products are to be installed in accordance with ANSI/NFPA 70, National Electrical Code (NEC) and
CAN/CSA-C22.1, Canadian Electrical Code, Part I (CEC).

28. Only UL Listed conduit, fittings, and/or other components are to be used.

29. Products are listed for installations with a maximum thermal resistance value of R-1 for floor covering that
can be placed on top of your product

King Electrical Floor Heating Cable Installation Manual

4

STEP 1: Inspecting and testing the cable and floor sensor

1.1 Take the cable out of the box and inspect it for any physical damage.

1.2 Test the insulation and the resistance of the cable and record data in the CABLE TESTING LOG listed

on page 6 of this manual. This is test #1.

1.3 The cable and sensor must be tested and recorded a minimum of 4 times during the installation for
the warranty to be valid.

1.4 Insulation Test:
This test ensures that the insulation jacket of the cable is
not damaged. A low value on the meter indicates the cable
has been damaged and must be replaced. Follow the
following steps:

A. Set the multi-meter to read ohms.

B. Connect the ground wire (braided un-insulated wire) to the
black test lead of the multi-meter and the red test lead to both
the black and white wires of the cold lead.

C. The meter should read “OPEN” or “OL”. If you get a different
reading, the cable is damaged, contact King Electric for support.

D. Record the readings on the cable tag and in the cable test log.

1.5 Resistance test:

This test measures the resistance of the cable which verifies
the continuity (no breaks) and that the cable has the proper
wattage rating.

A. Set the multi-meter to read ohms.

B. Connect the meter leads to the black and white old lead wires,
DO NOTconnect the ground wire.

C. Compare the resistance reading to the value specified in the
product selection table, it should read 10%. If the reading

+

-

is different, contact King Electrical for support.

D. Record the readings on the cable tag and in the cable test log.

Insulation Test

King Electrical Floor Heating Cable Installation Manual

Resistance Test

5

STEP 1: Inspecting and testing the cable and floor sensor.

1.6 FLOOR SENSOR TEST:

This test measures the resistance of
the floor sensor to verify the integrity
of the component.

A. Set the multi-meter to read ohms.

B. Connect the mulit-meter leads to
the floor sensor wires.

C. The meter should read between 8-25k
ohms depending on the ambient
temperature when taking the test.
If test results are not between 8-25k
contact King Electrical for support.

D. Record the readings on the cable tag
and in the cable test log.

(continued)

Typical sensor values:

55F (13C ) ________17,000 ohms
65F (18C ) ________13,000 ohms
75F (24C ) ________10,000 ohms
85F (20C ) _________8,000 ohms

CABLE TEST LOG

Tests must be recorded for warranty

Model:
Volts:
Factory QC Test
TEST 1. Before installation

TEST 2. After installation, but before
embedding

TEST 3. After embedding

Resistance

10%)

( +

Floor Sensor Test

Insulation

Test

TEST 4. After floor tile

King Electrical Floor Heating Cable Installation Manual

6

STEP 2: Layout planning and product selection

King Electric heating cable is used to warm interior floors. It is not to be used for exterior applications such
as snow melting or roof and gutter applications. It is not to be used in walls or ceilings. Follow these steps
in planning the installation:

2.1 Draw the room dimensions on a piece of grid paper.

2.2 Draw in any fixed obstructions such as a shower, bath tub, vanity or counter. The cable is not to be
installed under these type of items. In addition, DO NOT run cables into closets or confined areas
where heat could build-up.

2.3 Mark the locations of any toilets, heating vents or any other heating appliance. Note on the drawing
that the heating cable must be installed at a minimum distance of:

A. 6” from the center of the toilet drain.

B. 8” form heating vents or any other heating appliance.

2.4 Determine the heated area of the floor by subtracting the permanent fixtures. For example: Figure

1.5 the room is 10ft x 10ft equaling 100 square feet. (ft ). The area of each permanent fixture is as

2

follows:

A. Vanity = 10ft
B. Toilet = 3ft
C. Shower = 9ft
D. Total heated area: 100ft - 22ft =78 ft

2

2

2

2

2

2

10 ft

Vanity= 10ft

Toilet=3ft

2

10 ft

2

Shower=9ft

King Electrical Floor Heating Cable Installation Manual

2

7

STEP 2: Layout planning and product selection

(continued)

2.5 Border allowance: Heating cable should be installed between 1” and 6” from the perimeter walls, but not more
than 1.5” from a kick space vanity, shower, bathtub, counter or doorway. It is not necessary to heat the floor all
the way to the wall as it is not typical that people will stand that close to the walls. In addition, the heat will
radiate out an additional 2” from where the cable is embedded.

2.6 In most cases simply select the cable kit that is 5% but no more than 10% less that the total square footage of
the area to be heated as calculated in the previous step. For example: if the square footage after deduction the

2

2

fixed obstacles equals 74 ft , then the closest cable kit is 70 ft which is 5.4% less allowing for an unheated border.
The next size down is 60 ft which is too small and would not be enough cable to properly heat the room.

2.7 Selecting the cable spacing:

A. 3” is the standard spacing and recommended for most flooring heating applications.

B. 2” spacing is used for high heat loss applications such as a non-insulated concrete basement floor or bathroom
with a large exterior wall.
C. 4” spacing is used in low heat loss applications such as in warmer climates where there is a modest temperature
rise of less than 15 F is all that is needed.

2.8 Select either 120 or 240 volt cable depending on the power supply available. DO NOT mix voltages on the same
system when more than one cable is used to cover a room.

120V Length Heated area spacing (ft²)

Model ft m 2” 3” 4”

FC12120 40 12.2 5 10 15 120 1.0 120.0 20 ft.
FC12180 60 18.3 10 15 20 180 1.5 80.0 20 ft.
FC12240 80 24.4 15 20 25 240 2.0 60.0 20 ft.
FC12300 100 30.5 18 25 35 300 2.5 48.0 20 ft.
FC12360 120 36.6 20 30 40 360 3.0 40.0 40 ft.
FC12480 160 48.8 25 40 55 480 4.0 30.0 40 ft.
FC12600 200 61.0 35 50 65 600 5.0 24.0 40 ft.
FC12720 240 73.2 40 60 80 720 6.0 20.0 60 ft.
FC12840 280 85.3 45 70 95 840 7.0 17.1 60 ft.

FC12960 320 97.5 55 80 105 960 8.0 15.0 60 ft.
FC121080 360 109.7 60 90 120 1080 9.0 13.3 80 ft.
FC121200 400 121.9 65 100 135 1200 10.0 12.0 80 ft.

Watts

Amps

Ohms

Fast Set

Strapping

King Electrical Floor Heating Cable Installation Manual

8

STEP 2: Layout planning and product selection

240 Volt selection table

(continued)

240V* Length Heated area spacing (ft²)
Model ft. m 2 3 4

FC24240 80 24.4 15 20 25 240 1.0 240.0 20 ft.
FC24360 120 36.6 20 30 40 360 1.5 160.0 40 ft.
FC24480 160 48.8 25 40 55 480 2.0 120.0 40 ft.
FC24600 200 61.0 35 50 65 600 2.5 96.0 40 ft.
FC24720 240 73.2 40 60 80 720 3.0 80.0 60 ft.
FC24840 280 85.3 45 70 95 840 3.5 68.6 60 ft.

FC24960 320 97.5 55 80 105 960 4.0 60.0 60 ft.
FC241080 360 109.7 60 90 120 1080 4.5 53.3 80 ft.
FC241200 400 121.9 65 100 135 1200 5.0 48.0 80 ft.
FC241320 440 134.1 75 110 145 1320 5.5 43.6 80 ft.
FC241440 480 146.3 80 120 160 1440 6.0 40.0 100 ft.
FC241680 560 170.7 95 140 190 1680 7.0 34.3 100 ft.
FC 241920 640 195.1 105 160 210 1920 8.0 30.0 100 ft.
FC 242160 720 219.5 120 180 240 2160 9.0 26.7 120 ft.
FC 242400 800 243.8 135 200 265 2400 10.0 24.0 120 ft.
FC 242880 960 292.6 160 240 320 2880 12.0 20.0 120 ft.

“

“

“

Watts Amps Ohms

Fast Set

Strapping

* 240 volt cables are approved for 208 volt, but will produce 25% less wattage.
NOTE: Strapping is sold seperately, and is not included with cable.

STEP 3: Thermostat location and strapping layout

2.9 Draw in the locations of the strapping guides, making sure to identify both the center straps and
the end straps in your drawing. The end straps are used to turn the cable 180 degrees while the center
straps are used to hold the cable when the end straps are more than 48 inches apart.

King Electrical Floor Heating Cable Installation Manual

End Strap

Center Strap

9

STEP 3: Thermostat location and strapping layout

3.2 Mark the location of the thermostat on the drawing. This is where the cold lead will drop from the
wall box and become the starting point for the heating cable as well as where the floor sensor will
be installed.

End Splice

(continued)

T

Thermostat

Cold Lead

3.2 For walls or obstructions with angles or curves, the strapping can be cut into smaller sections and
installed as demonstrated in figure 1.7

Figure 1.7

King Electrical Floor Heating Cable Installation Manual

10

STEP 3: Thermostat location and strapping layout

(continued)

3.4 Determine the direction of the cable runs. It is recommended that the cable run parallel to the wall that the
thermostat is mounted. Center straps are required when the distance between end straps is more than
48 inches. Center straps should be 3 to 4 feet apart.

3.5 On average, a 5 to 10% deduction in heated area will create a 2-4” border. To determine the exact distance
to mount the strapping from the wall, take the actual room square footage less the selected cable kit less to
determine the unheated border. Then take the unheated border and divide it by the perimeter. Now multiply by
12 for the number of inches to mount the cable straps away from the wall.

A. 10ft x 10ft room = 100 ft

2

B. 4ft x 10ft = 40 ft perimeter

C. Cable kit selected 90 ft

D. 100ft - 90 ft = 10ft unheated border

E. 10ft / 40ft = .25ft

2

2

2

2

2

F. .25ft x 12in/ft = 3” from the wall

3.6 It is difficult to predict exactly where the heating cable will end, thus it is important to have a buffer zone.
A buffer zone is an area where heating in not essential and if unheated will go unnoticed. This area is also
used for any excess cable where a higher heated density will also be un-noticed.

Materials required

1. King floor heating cable

2. King floor strapping (sold separately)

3. King GFCI thermostat

4. King temperature sensor (included with thermostat)

5. King instant alert monitor, model FCS11

6. Electrical box and cable clamps

7. Wood chisel or router

8. Multimeter or megometer

9. Electrical wire connectors and cable fasteners

10. Nail plate (included with cable kit)

11. Duct tape

12. Stapler

12. Protective glasses

13. Tape measure

14. Broom

15. Felt tip marker

16. Electrician tools

17. Electric drill

18. Plastic trowel

19. Hammer

20. Hot glue gun

For installation on concrete slab add:

21. Double backed tape

King Electrical Floor Heating Cable Installation Manual

11

STEP 4: Electrical rough-in (New construction)

Mount Electrical Box

4.1 Determine the proper location and
height (typically 60”) for the
junction box. The cold lead and
the floor sensor lead wires should
be in the same stud cavity as the
electrical junction box. Install the
junction box for the thermostat and
run the power supply wires into the box.

Drill Horizontal Hole

4.2 Drill a 3/4” hole 1-1/2” deep horizontally
into the sill plate for the cable routing. Drill
the hole as close to the bottom of sill plate
as possible. Chisel out the bottom of the
sill so that the cold lead wire will not
create a high spot in the floor when
the thin-set is applied.

Drill Vertical Hole

4.3 Drill a 3/4” hole vertically into the sill plate
1-1/2” deep. If installing a floor sensor,
drill a second set of holes 4”away in the
same stud cavity.

4.4 Clear the cable routing holes of debris
and install in the same stud cavity.

King Electrical Floor Heating Cable Installation Manual

Install Nail Plate

4.5 It is recommended to thread a pull string
as the cable installation will be done after
the drywall is in place. Run a second pull
string if a floor sensor is being installed.
Otherwise the wires can be fished through
the wall with an electrician’s fish tape after the
drywall is installed.

12

STEP 4R: Electrical rough-in (For remodel)

Cut Hole for remodel J-box

4.1R Determine the proper location and
height (typically 60”) for the
junction box. The cold lead and
the floor sensor lead wires should
be in the same stud cavity as the
electrical junction box.

Install remodel J-box

4.2R Install a remodel type electrical junction
box for the thermostat and run the
supply power into the box.

Chisel channel

4.3R Remove base moldings as needed where the
cable routing holes need to be drilled.

4.4R Chisel out a 1-1/2” by 1-1/2” channel into
the sill plate 1-1/2” deep. If installing a floor
sensor, chisel a second relief 4” away in
the same stud cavity.

King Electrical Floor Heating Cable Installation Manual

Install Nail Plate

4.5R Install a nail plate to protect the wires.

13

STEP 5: Transfer layout to floor and plan cable routing

Vanity

Toilet

Shower

Plan routing of cable.

5.1 Use tape to mark the fixed objects in the room
the cable needs to avoid, such as a vanity,
shower or bathtub. These areas will remain
unheated.

5.2 Plan the cable routing around the fixed objects. It
is best to plan the cable runs parallel to the longest
wall in the room. Be sure to have a plan for the end
of the cable, including an overflow area to place any
excess cable. The cable MUST NOT be cut.

1” to 6” from wall

STEP 6: Installing the metal strapping

6.1 Each strapping kit includes a combination of end
and center strapping. End strapping is used around
the border while the narrow center strapping is used
to install between the end strapping when greater
than 4 feet apart.

Note: The strapping and heating cable are designed
as a complete system. using any other strapping or
mounting system will void the warranty.

Install end strapping

6.2 Heating cable should be mounted 1-1/2” from a
kick space, shower or bathtub and between 1-6”
from walls.

6.3 Start mounting the end strapping at the predetermined
distance from the wall on one side of the room, then
offset the end strapping by 3” on the opposite side of
the wall.This will allow for proper alignment of the
cable spacing. Tip: use of a chalk line will assist in
proper alignment of the end and center strapping.

King Electrical Floor Heating Cable Installation Manual

Cut strapping to fit

6.4 Strapping is designed to be cut into smaller sections
by using guides located every 6”. Cut the strapping
into smaller segments to fit the cable layout scheme.

6.5 On wood subfloors, the strapping should be fastened with
3/8” staples every 6” using the gap between the pre­ punched holes to center the staple gun. The strapping
can also be mounted using nails with .25” head or
#10 screws. Fasteners are required at the end of ends
of each individual piece of strapping to keep it secure.

14

STEP 6: Installing the metal strapping

(continued)

1” to 6” from wall

Installation in angled areas

6.6 For angled areas such as a corner shower, cut
6” pieces of end strapping then mount each
piece in a staggered fashion as shown.

Center strapping

6.7 When end strapping is greater than 4ft apart, then the
center strapping must be installed to secure the cable.
Snap a chalk line between the end strapping using the
diamonds punched in the strapping to align the centers.

6.8 For installation on concrete surfaces the metal
strapping may be attached using double side
tape, hot glue or concrete anchors.

King Electrical Floor Heating Cable Installation Manual

Fasten Strapping

15

STEP 7: Installing the cold lead

Shower

Uncoil Wire

7.1 It is important to properly uncoil the cable to prevent
twisting and pig tailing. Insert a rod into the spool hub
and let the spool unreel as shown. Unreel the power
leads of the cable up to the factory splice and feed
it up the wall into the thermostat junction box. The
factory splice MUST BE mounted on the floor and
MUST NOT be installed in the wall.

7.2 Due to the large diameter of the cold lead splice, a
.25” deep channel must be cut into the floor to avoid
interference with the finished floor. For a wood floor
Use a router or wood chisel. For a concrete floor, use
An appropriate masonry chisel or power hammer.
Remove any debris to avoid damage to the cable.

Chisel .25” Grove

7.3 Secure the cold lead splice into the chiseled channel
with hot glue. DO NOT USE SCREWS OR STAPLES TO
SECURE THE COLD LEAD.

IMPORTANT:
THE COLD LEAD SPLICE MUST BE FULLY EMBEDDED
IN THE MORTAR. In addition, the cold lead splice
Must not be bent. No portion of the cold lead should
Enter into a wall or drop through a subpolar.

Hot Glue Spice

7.4 Secure any loose (blue) heating cable between the
start of the run and the location where the cable is
first laced through the strapping. Use the single hole
straps provided.

King Electrical Floor Heating Cable Installation Manual

Cut strapping to fit

Install Cable Monitor

7.5 Install the cable monitor and leave it connected
throughout the entire installation process until
the tile has set. If the cable monitor sounds an
alarm, stop and check the cable for damage.
The cable is only to be repaired with a factory
splice kit.

16

STEP 8: Lacing the cable through the strapping

Lace around end straps

8.1 Begin at the cold lead splice by running the blue
heating cable into the first end strap. Pull the cable
around the end strap keeping light tension on the
cable while seating it under as well as all the way
into the tabs. The tabs are designed in a semicircle
creating a 180 degree turn while maintaining the
proper 1” bend radius.

8.2 Lace the heating cable back and forth while maintaining
light tension. Lace across the area desired spacing, DO
NOT space cable closer than 2”. DO NOT pull the cable
too tight. It is only necessary to create enough tension to
keep the cable from lifting up when applying thin set.

Weave cable back and forth

8.3 Once the area is completed, lightly press down the
center straps and one hole straps to secure the cable.
DO NOT use a tool, push lightly by hand. It is not
Necessary to clamp the cable firmly, apply just
enough pressure to keep the cable from coming up
when applying the thin set. It is not necessary to push
down the end straps as the tension on the cable will
be hold under the tabs in the semicircle.

Push down center strap tabs

8.4 At the end of the run use the one hole strapping pieces,
cut from the center strapping to secure the cable.
ALWAYS maintain a minimum distance of 2” spacing.

IMPORTANT: NEVER LAY ONE CABLE OVER THE TOP OF ANOTHER.
NEVER STAPLE OVER A CABLE, AND ONLY USE
STRAPPING TAB TO HOLD DOWN THE CABLE.

King Electrical Floor Heating Cable Installation Manual

Chisel grove for end splice and secure

8.5 The tail splice is slightly larger in diameter than the
heating cable and must be recessed into the subfloor.
Make a .25” channel into the subfloor and secure the
tail splice into the channel and secure with hot glue.

17

STEP 9: Install the floor sensor

Position floor sensor halfway
between the heating cables

9.1 The floor sensor must be positioned exactly halfway
between two heating cables to accurately read the
floor temperature. Place the sensor bulb at least
12” into the heated area. Mark the spot on the floor
where the sensor bulb will be located.

9.2 To make sure the sensor bulb will not create a high
spot in the floor, chisel a .25” channel into the floor
and lay the sensor bulb into the channel. Apply hot
glue to secure the bulb into place.

STEP 10: Apply scratch coat

Test cable before embedding

9.3 Use a fish tape or pull string to pull the sensor
wire to the electrical box, but not in the box.

IMPORTANT TEST 2: Test the cable resistance, cable
insulation and floor sensor now
that the cable is installed on the
floor. Record the readings on the
cable label and the data table on
page 6.

10.1 Apply a scratch coat of thin-set or self-leveling mortar
uniformily over the entire floor area. Make sure the
heating cables are completely embedded. Follow the
compound manufacture’s instructions.

10.2 Use a plastic straight edge trowel and cover the entire
areas that don’t have cable to maintain uniform height.

10.3 Apply the mortar in the same direction of the cable runs
to minimize lateral movement.

IMPORTANT TEST 3: TEST THE CABLE RESISTANCE, CABLE
INSULATION AND FLOOR SENSOR

Scratch coat application

King Electrical Floor Heating Cable Installation Manual

RESISTANCE TO BE SURE NO DAMAGE
OCCURRED DURING THE THIN-SET
APPLICATION. RECORD THE READINGS
ON THE CABLE LABEL AND IN THE DATA
LOG ON PAGE 6.

18

STEP 11: Install the thermostat

Lace around end straps

Thermostat wiring diagram

Line voltage connection

11.1 Before starting any wiring, verify that the power
supply is turned off.

11.2 Connect the power supply wires and the load side
heating wires. Follow the thermostat manufacturer’s
instructions.

CAUTION:

Allow mortar compound to completely
cure before energizing cable. This will
ensure that the setting of the mortar mix
will not be compromised by the heat of the
cables. Refer to compound manufacturer’s
instructions for curing times.

11.3 Connect the floor sensor wires to the thermostat.
These are low voltage wires and should not enter
the line voltage junction box. These low voltage
wires typically run through the wall, as shown and
connect into the face of the thermostat away from
the line voltage wires.

Floor sensor wires

Low voltage connection

King Electrical Floor Heating Cable Installation Manual

Instsall thermostat faceplate

19

King Electrical Mfg. Company will repair or replace, without charge to the original owner, any heating cable found to be defective or malfunctioning within the 20 year warranty.
In Case of Product Failure: Contact King Electrical Mfg. Co. at 800.603.5464. The owner will be required to provide, within the designated warranty period, the following information:
model number, date of purchase, and a complete description of the problem encountered with product. Upon receipt of the aforementioned, the company will reply to the owner within
a period not to exceed fifteen (15) working days, and will provide the action to be taken by owner. Terms: This warranty requires the owner or his agent install the equipment in
accordance with the National Electrical Code, any other applicable heating or electrical codes and the manufacturer's installation instructions. It further requires that reasonable
and necessary maintenance be performed on the unit. Failure of proper maintenance by owner will void the warranty in its entirety. The company is not liable for any actions it deems
to be abuse or misuse of the product. The customer shall be responsible for all costs incurred in the removal or reinstallation of products, including, but not limited to, labor costs, and
shipping costs incurred to return products to King Manufacturing. At their discretion, King Manufacturing will decide to either repair or replace the product, with no charge to the
owner, with return freight paid by King. The Company shall not be liable for consequential damages arising with respect to the product, whether based upon negligence, tort, strict
liability or contract. No other written or oral warranty applies, nor any warranties by Representatives, Dealers, Employees of King or any other person. King Manufacturing can be
contacted by phone at 206.762.0400, fax [phone] or website www.king?electric.com.The company's minimum liability shall not in any case exceed the list price for the
product claimed to be defective.