Expansion sleeves for PVC conduit?

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Old 11-24-18, 07:13 PM
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Expansion sleeves for PVC conduit?

Running power to detached garage though PVC conduit. Probably 1 1/2" maybe 2" diameter. Total underground run is about 60'. Do I need expansion sleeves at the vertical rise of the conduit? If so can the expansion sleeve be partially buried? LB connector at the house is about 16" above the ground. Do I need expansion sleeves on the buried horizontal section of conduit?

Thanks
Tim
 
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Old 11-24-18, 07:38 PM
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It depends on your climate and sun exposure length of run etc. NEC calls for expansion joints if more than .25 inch of expansion between fixed points. There are online charts to estimate pvc conduit expansion.
 
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Old 11-25-18, 11:15 AM
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I live in climate zone 5. So temps vary from 90's during summer to a little below 0 in the winter. Conduit will about 48" above ground exposure at ( north side so shady) garage and at house 20" to top of LB connector ( facing east so morning sun then shade)

Conduit will be buried at least 18" possibly deeper if soil isn't rocky. Will the buried conduit expand that much? If so will it even be able to expand/contract being buried and all?
 
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Old 11-25-18, 11:34 AM
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The buried conduit doesn't expand at all. It's the conduit exposed to the sun from the ground to the LB. Originally you said the LB was 16" off the ground. 16" of exposed PVC will have minimal expansion. 48" is a big difference and should probably have an expansion coupling in it.
 
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Old 11-25-18, 03:24 PM
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Thanks for the reply pjmax. The conduit is not below the frost line I still don't need to worry about expansion?
 
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Old 11-26-18, 09:02 AM
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No you generally do not install an expansion joint on "free floating" underground lines. The elbow sweeps can wiggle enough in the soil to take up the minimal expansion that occurs underground. However you do need the expansion joint in the 48" vertical as the pipe will break when the soil is frozen and the LB is also solidly held where it goes through the framing.

Often you will see these installs after a couple years with a snapped glue joint on the long side of the LB serving as a defacto expansion joint.
 
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Old 11-27-18, 05:21 PM
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Thanks everyone for the advice
 
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