How would you do it.....

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1793

Senior Member
Location
Louisville, Kentucky
Occupation
Inspector
I have been asked to repair some PVC conduit that is pulling away from the building. Plastic anchors used on 1-1/4" PVC with 3 #3's. The run is about 80'. Supported from above every other "rib", about 4' apart.

I'm thinking unistrut with 3 to 4 TapCons at each of the existing strap locations. Catching both runs of conduit.

Would this work?
 

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Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I don't understand why it fell off the ceiling straps. Is the wood rotten. I would try and mount it back with some 2 hole straps up to the roof rafter tails.
 

JES2727

Senior Member
Location
NJ
Those 'rafters' look like masonry to me. Tapcons will work if the masonry is in good condition. Otherwise, I'd try expansion anchors, and 2 hole straps. Not sure I see the necessity for unistrut.
 

1793

Senior Member
Location
Louisville, Kentucky
Occupation
Inspector
Those 'rafters' look like masonry to me. Tapcons will work if the masonry is in good condition. Otherwise, I'd try expansion anchors, and 2 hole straps. Not sure I see the necessity for unistrut.

I'm thinking that the unistrut will allow for more anchor opportunities and disperse the weight of the downward pull. since stand off straps were used I was thinking the unistrut would keep the spacing about the same.
 

Cow

Senior Member
Location
Eastern Oregon
Occupation
Electrician
When was the last time you saw someone use those straps on PVC electrical conduit? I've seen the plumbers use them on copper pipe.

I've used them before in a very humid dairy barn where the temperature varied a lot. The kind I used were from T&B, my electrical supply house was able to get them. I think I bought the 1 1/8 OD straps for 3/4 and they fit perfect. Just snug enough so the pipe couldn't wiggle but just loose enough it could slide back/forth through the strap.

When I was trying to find them, I believe McMaster Carr had a whole bunch of different types too, zinc, stainless steel, etc.
 

donselectric

Senior Member
Location
nh
why did they use mini's for pvc in the first place for?? also i didnt see an expansion fitting which is why it prob pulled out. use the existing hole and drill another and use pvc two hole clips and cut an expansion fitting in... thats what i'd do and should have been done in the first install...
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I am confused are you talking about unistrut straps for PVC???? Caddy has this info. from this link.

Features

Minimizes dropped parts and increases efficiency
Handles heavy loads
Installs with a screwdriver or a nut driver
Available in various materials and finishes
Alternative to traditional 4-piece hardware
Models available for Rigid, EMT, copper, PVC/CPVC
 

iwire

Moderator
Staff member
Location
Massachusetts
I am confused are you talking about unistrut straps for PVC????

In my personal opinion using those straps in the link to secure PVC for an NEC application is an NEC violation.

352.30 Securing and Supporting. PVC conduit shall be
installed as a complete system as provided in 300.18 and shall
be fastened so that movement from thermal expansion or contraction
is permitted.
PVC conduit shall be securely fastened
and supported in accordance with 352.30(A) and (B) or permitted
to be unsupported in accordance with 352.30(C).

There is no way to leave those type of straps loose to allow movement of the PVC.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
In my personal opinion using those straps in the link to secure PVC for an NEC application is an NEC violation.

There is no way to leave those type of straps loose to allow movement of the PVC.

In that case every strap would be a violation. I don't see why you can't leave them loose-- just don't tighten them down. Couldn't you just use a strap one size larger.
 

tkb

Senior Member
Location
MA
How far apart are the existing supports?
For 1-1/4" to 2" the supports cannot be less than 5' apart.
 
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