SlabHeat Installation Manual

12
SPECIAL APPLICATIONS
STEP 3.10
Expansion Joints: Heating cable must never be run through an expansion joint. Doing so may cause damage to the cable with
slab movement. It is recommended to lay the cable so these joints are avoided.
However, if it is necessary, a portion of the heating cable may be dropped into the grade below the expansion joint as shown. Fill
around the cable with at least 1 inch thick sand. The loop of heating cable should be long enough to allow flexing, and must not be
embedded into the concrete (the sand should protect against this) since this would not allow the cable to flex with slab movement.
STEP 3.6
Use a digital multi-meter to measure the resistance between
the conductors of the cable power leads again. Record these
resistances in Table 4 under “After cable is secured in place".
STEP 3.7
Feed the power leads through the conduit into the junction box,
leaving at least 6 inches of free lead length. Secure the heating
cable and splice so that they will not be pulled into the conduit.
Insert a generous amount of electrical conduit sealant into the
conduit end around the power leads to prevent water entry.
STEP 3.8
Feed the sensor wire through the sensor conduit, leaving at least
6" of free lead length at the control electrical box. If the sensor tip
is directly embedded in the slab, secure it using a cable tie. Make
sure the sensor tip is located about 1" below the surface, half-way
between heating cables, and at least 1' into the heated area.
STEP 3.9
Take a photo of the cable installation. This can be very helpful later
for utility work, changes to the site, etc. to avoid possible damage.
Keep the photos with this installation manual and provide to end
user upon completion.
Expansion Joint
Gravel
Heating Cable
Protected to prevent
concrete encasement
Sand
Concrete
Top-Down view of SlabHeat cable and the
slab sensor entering slab.
SlabHeat Cable
In-slab sensor
Conduit
Power Lead
Factory Splice
(in concrete, not in conduit)