Pipe clamp listing

[Jpflex]

Quick question

If supporting and protecting feeders going to a sub panel with strut bars and 1/1/4 schedule 40 rigid non metalic conduit but the package for the 1/1/4 metal pipe clamps do not specifically have NMC listed for use then would this be NEC code compliant?

I noticed local utility used this configuration.

 

[Jpflex]

Utility used this configuration so I suppose it’s common practice or allowed?

 

[don_resqcapt19]

That type of support clamp does comply with the requirement in the parent text of 352.30. The requirement that that type of clamp does not meet is: shall be fastened so that movement from thermal expansion or contraction is permitted".
This rule is rarely complied with, but it is a rule.

 

[LarryFine]

We commonly use RGC or EMT hardware on PVC.

 

[AC\DC]

We commonly use RGC or EMT hardware on PVC.

How do you get emt straps to fit? Tight when I grab them.

 

[LarryFine]

How do you get emt straps to fit? Tight when I grab them.

You usually need to go up one size because of the thickness of PVC conduit. Each strap type, EMT vs RGC, is a slightly different size due to the difference in conduit wall thickness.

Before buying, I go to the store and test-fit 1-hole straps of both kinds on the PVC conduit I will be using, looking for the closest-but-still-loose fit to allow for expansion travel.

 

[Rick 0920]

You can still use HW strut straps, just snug them up enough to where the conduit can move for thermal expansion. Some strut straps are labeled Universal and will work with thinwall or heavywall conduits.

 

[Jpflex]

Interes

That type of support clamp does comply with the requirement in the parent text of 352.30. The requirement that that type of clamp does not meet is: shall be fastened so that movement from thermal expansion or contraction is permitted".
This rule is rarely complied with, but it is a rule.

Interesting, however the calms are able to shift along strut bar and as long as clamps are not too tight expansion and contraction will be possible. Therefore, it seems this may be an inspectors discretion?

 

[kwired]

You usually need to go up one size because of the thickness of PVC conduit. Each strap type, EMT vs RGC, is a slightly different size due to the difference in conduit wall thickness.

Before buying, I go to the store and test-fit 1-hole straps of both kinds on the PVC conduit I will be using, looking for the closest-but-still-loose fit to allow for expansion travel.

If it is loose enough to allow expansion/contraction it is loose enough to move laterally in the strut, or even allow the screw to eventually come unthreaded.

I have in the past used a larger sized piece of tubing (PVC, EMT, whatever you wish) slipped over the PVC and clamp that sleeve in the strut/clamp, then it is free to expand/contract all it wants and you still can have pretty secure clamping.

 

[LarryFine]

If it is loose enough to allow expansion/contraction it is loose enough to move laterally in the strut, or even allow the screw to eventually come unthreaded.

I was referring to 1-hole straps, not strut.

 

[don_resqcapt19]

Interes

Interesting, however the calms are able to shift along strut bar and as long as clamps are not too tight expansion and contraction will be possible. Therefore, it seems this may be an inspectors discretion?

Not the correct direction to take care of expansion and contraction of the PVC conduit.

 

[don_resqcapt19]

I often see the next large size two hole straps used for this.
Or you can special order this type. B-Line B2417 pipe guide.

 

[4-20mA]

PVC conduits OD's are the near the same as rigid sizes last I knew. Use a rigid 1 1/4" strap and roll on...

Don't get me started on the Robroy strut straps though... that's a whole other can of worms

 

[readydave8]

You can still use HW strut straps, just snug them up enough to where the conduit can move for thermal expansion. Some strut straps are labeled Universal and will work with thinwall or heavywall conduits.

Most products that work with many things, wok well with none