8
Additional Items
Conduits (6,7)
Conduits (supplied on site) are required
to protect the
• fl exible connection lead and crossover
with the rigid/fl exible connection lead
• sensor connection lead.
Electrical Control Equipment
If Raychem standard panels are not
used, further items will be required to
complete the system:
• contactors
• circuit breakers
• residual current device (rcd) 30 mA.
(Multiple heating cable circuits up to a
total length of 167 m may be protected
by a single 30 mA rcd).
• One 300 mA rcd can be used to
protect up to 1500 m EM-MI heating
cable. Note, though, that drain tracing
must be protected by a 30 mA rcd in all
cases.
Storage
• Storage temperature range: –40°C to
+60°C
• Store all system elements in a clean,
dry place.
Equipment
• 2500 V insulation resistance tester
(min. 500 V)
• Ohmmeter
Preparing the Substratum
The heating cable is normally laid on fi rm
substratum. In the case of sloping ramps,
the substratum is backfi lled and the heat-
ing cable is laid on the reinforcement or
rolled asphalt. In suspended structures
the substratum may consist of fi nished
slabs, prestressed concrete or a sus-
pended structure with poured concrete.
Steel beams or planks with a concrete
surface are also permissible.
A suspended structure is normally cov-
ered by an asphalt layer to prevent water
penetration.
The heating cable can be laid on any of
these surfaces. In the case of poured
concrete, though, it should be ensured
that the surface is smooth and all sharp
objects are removed. Roadways on a
solid substratum do not require any ad-
ditional thermal insulation.
Appropriate preparations should be
made for installing the temperature and
moisture sensor. If using hot asphalt, a
spacer ring or similar should be used to
protect the sensor and supply lead from
the high asphalt temperature, as other-
wise the electronic components may be
destroyed. The remaining space can then
be fi lled once it has cooled. Please note
that to ensure long-term stability, any
exposure of the sensor and supply lead
to an ambient temperature of up to 80°C
must be kept as brief as possible. For fur-
ther details, please refer to the operating
instructions for the sensor.
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