| In any application where a flexible duct
is placed in a trench, product selection and proper installation is critical
to successful cable pulls. All flexible products can undulate, which will
result in excessive friction and difficult cable pulls even for distances
as short as 100 feet. Fledxible duct must have tension applied to it during
backfilling to prevent the duct from being moved by the backfill material.
To prevent cutting or crushing the duct, large rocks or backfill containing
heavy or sharp material should never be used.
Only 1-1/2" or 2" ID duct should be employed; this
larger diameter provides less surface contact (and therefore lower friction)
and is more likely to provide a successful installation.
CABLE CHASE is designed for trench applications.
Cable Chase is stiffer and has greater crush resistance than standard
corrugated-type ducts. It is very important that Cable Chase have
tension applied to it during backfilling, this will prevent it from snaking
in the trench. Proper bedding material, sand or fine gravel, is also important.
Cable Chase is ideal for making sweeps into a pedestal because
of its corrugated cnstruction; no other product combines its flexibility
and strength.
SUPER-CORR is a unique product also designed
for trench applications; it has little memory and exceptional crush resistance.
As with any flexible product, Super-Corr should have tension applied
to it when backfilling the trench. However, Super-Corr will not
deflect as easily as a corrugated product, nor is it likely that it will
be damaged by backfill material. Super-Corr is stiffer than Cable
Chase and will not bend into a sweep as easily.
ENDUCT Smoothwall (or Enduct Ribbed)
duct is very strong relative to crush resistance, but it has a great deal
of memory and can be difficult to embed in a trench in cold weather. All
smoothwall-type products will attempt to re-coil after removal from their
packaging reel. However, when care is taken to keep it straight during
backfill, Enduct can provide a satisfactory installation.
ENDOCOR, Standard Corrugated innerduct,
is not recommended for trench applications; it is too flexible and has
limited crush resistance. If Endocor is used in a trench, it is
critical that careful installation procedures be followed, with tension
applied during backfilling and clean, fine backfill materials used.
NOTE: Selection of the appropriate product and
proper installation is the user's responsibility. Endot assumes no responsibility
for improper installation that results in high pull tensions or duct restrictions
due to crushing of the duct during trench backfilling.
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