PVC expansion coupling

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infinity said:
Looks good with PVC nice and straight. :cool:
Me being very anal I probably would have bent an offset in the pipe to keep it tight to the wood but that would be a lot of extra work for zero benefit other than to look at it.
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Yeah I do prefer tighter to the wood, the lower the profile the better. Looking at it again it seems I did have enough real estate to recess the nose and use a box adapter in the panel, not sure why i didn't. Anyway, the strapping and expansion coupling detail is the important thing.
 
Logisticsman said:
One thing I am not certain of/familiar with is the securing of the PVC to the wall. I know that when using an expansion coupling the PVC needs to be somewhat loosely mounted to the exterior wall so that the expansion joint can move freely.
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You are correct that if you rigidly fasten PVC immediately below the expansion joint, you defeat the purpose of even having an expansion joint. That's a common mistake you see in practice, from an installer who doesn't see the issue. You'd either need a strap that allows for axial movement, or you'd need to strap above the expansion joint. If you can find a strap that fits it, you can in concept strap the upper body of the expansion joint as Electrofelon has demonstrated. There isn't a manufacturing standard for these fittings to coincide with the next size up in their outer diameter, so it isn't a guarantee that a strap will fit it.

Generally speaking, plastic PVC straps on PVC will allow axial movement, while metal straps will not. The plastic straps grip it more loosely with a lower friction coefficient, and secure it primarily against lateral movement. It is OK to use metal straps on PVC, as long as it is a section of PVC where you don't need to accommodate axial movement and thermal expansion.
 
infinity said:
Arlington makes a slip fitting where you actually use two different sized raceways (the larger slips over the smaller) as an expansion fitting.
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Sounded interesting, so I looked it up, but it's just a 2-1/2" x 2" PVC reducing male adapter.

The ID of 2-1/2" Schedule 40 PVC is 2.445", so it fits over 2" PVC conduit, which has an OD of 2.375". Schedule 80 won't work for the 2-1/2" sleeve, the ID is too small.

Cheers, Wayne
 
wwhitney said:
Sounded interesting, so I looked it up, but it's just a 2-1/2" x 2" PVC reducing male adapter.

The ID of 2-1/2" Schedule 40 PVC is 2.445", so it fits over 2" PVC conduit, which has an OD of 2.375". Schedule 80 won't work for the 2-1/2" sleeve, the ID is too small.

Cheers, Wayne
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Good to know, I wasn't sure about the sizes available.
 
wwhitney said:
Sounded interesting, so I looked it up, but it's just a 2-1/2" x 2" PVC reducing male adapter.

The ID of 2-1/2" Schedule 40 PVC is 2.445", so it fits over 2" PVC conduit, which has an OD of 2.375". Schedule 80 won't work for the 2-1/2" sleeve, the ID is too small.

Cheers, Wayne
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I often make my own expansion coupling (when using 2") by using a piece of 2 1/2 with a TA and sleeving it over the 2". Usually a piece of strut and a strut strap on the 2 1/2" , the 2" floating. I like this better than those factory "slip riser" fittings because not only is it cheaper, but also having a 2 1/2 TA, you and up without a concentric in some equipment.
 
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