3
Heating Cable Repair
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nVent.com
Hot/hot and Hot/cold joint:
Use the tube cutter to lightly
score the sheath on the exposed MI heating cable approx.
3/16” (4.8 mm) from end of the cable (for a hot/hot repair,
this is necessary for both ends). With diagonal cutters,
remove the sheath up to the score mark (Figure 10). Refer
to Appendix F for details on stripping the cable sheath.
Score
Figure 10: Stripping the MI heating cable sheath
Verify continuity of all conductors using a multimeter or
ohmmeter. See Appendix B for details.
Check the insulation resistance (IR) of the cable
sections at this point using a 1000 V DC Megohmmeter
(Figure 11). Further details on IR testing can be found
in Appendix B. The IR test checks for the presence of
moisture in the magnesium oxide insulation. A value
greater than 20 MΩ should be attained. If the IR is lower,
remove the moisture from the cable by following the
drying out
procedure in Appendix D. Ensure IR is 20 MΩ
minimum before proceeding.
Figure 11: Measure the insulation resistance.