3
Heating Cable Repair
32 | nVent.com
nVent.com | 33
Again, test the insulation resistance with a 500
volt Megohmmeter. Minimum IR should be 20 MΩ.
Quench with a rag soaked in water by wrapping it
tightly around the joint. Leave on for 4 to 5 minutes.
If there are any remaining pinholes, moisture will be
absorbed into the joint as it cools and the reading on
the Megohmmeter will drop. Joint must be cool to
get a proper IR reading.
Figure 40: Check insulation resistance
Water soaked rag
Figure 41: Wrap joint with water soaked rag
Note: If the Megohmmeter reading declines,
file off all solder from over brass screw and drive
out the moisture from the cable as described
in Appendix D; the Megohmmeter reading will
increase when the cable is dry. Once the moisture
is removed, touch up the solder as necessary and
retest. If still low, repeat procedure once more and
retest. If still low, replace joint.