When is it required in the NEC to install an expansion couping on a horizontal run of Schd #40 PVC conduit ? In other words what is the MIN length that it is required ? Also how about under a mobile /manufactured home where the conduit is used as feeder to the home?
expansion couplings required?
- Thread starter elecmen
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- New Jersey
- Occupation
- Journeyman Electrician (retired)
Have you taken a look at Table 352.44? You will need to know the temperature change for the area in which it's installed.
- Location
- New Jersey
- Occupation
- Journeyman Electrician (retired)
You're allowed up to 1/4" of expansion and need to factor in the temperature change. For us that's about 100? F. That means we can go a little over 6' between fixed points without an expansion fitting.
- Location
- Illinois
- Occupation
- retired electrician
You can't know the minimum length without knowing the temperature range that the raceway is exposed to. You need one where the calculated movement is 1/4" or more. Around here you can get that amount of length change in about 5' of conduit.
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