Install Instructions

IOM-WR-SH 1528 10 of 24
Phase 2 - Electrical Rough-in
To prevent the risk of personal injury and/or death, make sure power is not
applied to the product until it is fully installed and ready for final testing. All
work must be done with power turned off to the circuit being worked on.
Circuit Breakers and Supply Wire
Cable(s) Supply Wire Breaker
VAC total amps (AWG)* qty type** rating
120 up to 12 amps 14 1 SP 15 or 20 A
120 up to 15 amps 12 1 SP 20 A
240 up to 12 amps 14 1 DP 15 or 20 A
240 up to 15 amps 12 1 DP 20 A
* Recommended only. Follow local codes for wire gauge size.
** SP= single-pole, DP=double-pole
Table 5
STEP 2.1
Circuit Breaker (Overcurrent Protection)
SlabHeat installations must be protected against overload by a circuit breaker. GFCI type
(ground fault circuit interrupter) or AFCI type (arc-fault circuit interrupter) breakers may be used
if desired, but are not necessary when using SunStat controls with integral GFCI.
The rating of the breaker is determined by the amp draw of the cable (see Table 5). Add the
amp ratings of all cables to be connected to the SunStat (see Table 2 or the Nameplate Label
on the cable). If the total is less than 12 amps, use a 15 or 20 A breaker (preference is 15 A).
If the total is between 12 and 15 amps, use a 20 A breaker. If the total is over 15 A, another
circuit will be required with its own breaker and SunStat.
STEP 2.2
Install Electrical Boxes
SunStat Thermostat: Install an extra-deep electrical box for the SunStat thermostat. Follow
the instructions included with the SunStat for complete information on location and wiring.
SunStat Relay: Install an extra-deep electrical box for any SunStat Relay(s). The SunStat Relay
is used when more than 15 amps must be controlled by one SunStat thermostat. Follow the
instructions included with the SunStat Relay for complete information on location and wiring.
Junction Boxes: If a cable is to be located so its Power lead is not long enough to reach the
SunStat thermostat or SunStat Relay directly, a junction box must be installed. Do not attempt
to make a connection to other wiring without a junction box. Use a standard junction box with
a cover, mounting it below the subfloor, in the attic, in the wall, or in another location easily
accessible after all coverings are complete. If the SunStat sensor wire is not long enough to
reach the SunStat directly, it may be extended. A junction box may be required by local code to
make this connection. Follow the installation instructions included with the SunStat for details.
For construction with an existing wall or where the wall is covered, cut the necessary openings
to mount the electrical boxes listed above. Wait to install the boxes until all wiring is fed into
these locations to make it easier to pull the wire.
It may be possible to tap into
an existing circuit as long as
there is adequate capacity for
the cable(s) and any additional
appliance, such as a hair dryer
or vacuum cleaner. Avoid
circuits which have lighting,
motors, exhaust fans, or hot
tub pumps due to possible
interference.