I've never heard anything against using them. I would consider using them if I needed strong support and corrosion was not a concern. They would have to be the right size which would be for rigid (GRC) trade sizes not thinwall (Emt) sizes.
Was there something that you didn't like about using metal straps?
#77117 - 04/27/0108:42 PMRe: PVC with rigid straps
Well no! I did a 400A 500 cu kcmil 3ph riser in 4" Sch 80 a while ago. Used beeline & 4" conduit clips every 24" . The steel clips do not allow for the expansion of pvc, and are not listed for it's use. But the plastic clips are whimpy, and this riser's 4-500's wieghed out to more than they are rated for! Me....I'd rather see the pvc pull apart than fall off the building
[This message has been edited by sparky (edited 04-27-2001).]
#77118 - 04/27/0109:06 PMRe: PVC with rigid straps
I've always preferred using metal straps, but lately I've been learning a lot about a few of my assumptions about the NEC, and I had a feeling there was something hiding somewhere to prevent their use if they manufactured PVC straps.
Sparky has a good point about the expasion thing... I usually use 1 hole GRC straps... Any difference here?
-Virgil Residential/Commercial Inspector 5 Star Inspections Member IAEI
#77119 - 04/28/0106:35 AMRe: PVC with rigid straps
Virgil; try the 'quick-clips' for the small stuff. they live up to their name, quick...snap your pipe right in, comes out easy if needed, maintains the 1/4" standoff in wet/damp locations. I snap a line first....
#77120 - 04/28/0108:14 AMRe: PVC with rigid straps
I got called on metal straps once @ the beach because of the salt air, but can't imagine why they would cause a problem elsewhere. The code requires expansion joints where more than 1/4" of linear expansion is expected, and the diametric expansion can't be all that great. And yes, those PVC straps are whimpy.