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2
Pre-Repair Information
2.3
Changes to the Heating Cable Length
A new tag is not required for repaired or modified
heating cables provided the total length of the
heated section of the cable is not changed by more
than 3%. Where the heated section of the cable set
is changed by more than 3%, to facilitate the repair
or where the cable is modified, then a new MI cable
tag must be ordered. In these cases, the MI Heating
Cable Field Modification Approval Request Form in
Appendix A must be filled in and reviewed by nVent
before proceeding with the repair or modification
and a permanent record of the modification must be
retained.
Caution: Shortening the length of the heated
section will decrease the resistance,
resulting in increased current draw and wattage.
Similarly, increasing the length of the heated
section will increase the resistance, resulting in
decreased current draw and wattage. Pay special
attention to the over-current protective device to
ensure that it will still conform to the
requirements of national and local codes when
such modifications are made to heating cables.
WARNING: A significant decrease in the
length of the heated section may result in a
considerable increase in wattage and cable sheath
temperature with the potential of starting a fire.
Verify the cable design before applying power.