Set screw type fittings

Status
Not open for further replies.
B

bcorbin

Senior Member
I would say I call for compression-style conduit fittings on the majority of my jobs. I do mostly commercial, health-care, and schools. I assume the compression style fittings are a bit more expensive than set-screw type. Are they overkill? Is there any other advantage than simply being concrete-tight and water-resistant?
 
My preference is steel setscrew type.
Raco's are listed as concrete tight "when taped".
Not all compression fittings are listed as raintight.
I think I have seene more loose, disjointed compression couplings above ceilings than any other type. Maybe the guy only had one wrench.
db
 
barclayd said:
My preference is steel setscrew type.
Click to expand...
Same here, ever since I discovered they're competitively priced with cast, and I believe they're vastly superior.

I've broken cast connectors just tightening the locknut, and stripped the setscrew hole, too. Maybe I have gorilla mitts.

I think I have seene more loose, disjointed compression couplings above ceilings than any other type.
Click to expand...
Agreed again. I've had stubs-up in walls come out of their connectors, and it's a pain to get it back into the connector and pointing the right way.

The good news is that you can tighten the connector by rotating the EMT. The bad news is you can loosen the connector by rotating the EMT.
 
IMO steel set screw are the best. They're easier to install than compression and stronger since they indent the conduit. A study done years ago following an earthquake in Ca. determined that steel set screw fitting had the lowest failure rate.
 
barclayd said:
My preference is steel setscrew type.
Click to expand...

Mine too.

I had a spec on a group of O.R.'s once that specifically stated compression type fittings were not allowed.

Even though I liked this and didn't want to buck the engineer I had to ask him why his spec read this way, he said he had more confidence that the set screw fittings would be able to be tightened in tight spots verses a compression fitting.

Roger
 
I haven't done any commerical in a long time, but the only issue I ever had with set screw couplings is that on a long run they leak too much for a vacuum fish tape system.
 
I have not had the opportunity to use a milliohm meter to check, but I would guess that a properly made-up steel compression coupling will have a lower impedance than a properly made-up set screw coupling. There just seems to be more surface area contact.
I have dedicated EGC's installed anyway, but I like to have the raceway as a low impedance path for accidental contact and reduction of static charge build-up.
Keep in mind that my perspective is based on doing work in "critical" buildings.
I also like it that Roger's Engineer is using his head, but I think that a talented EC can make-up a good steel compression fitting just about anywhere. I like to think that a majority of the guys that work on my projects are that talented, maybe they're just snowing me. :)
 
ron said:
I like to think that a majority of the guys that work on my projects are that talented, maybe they're just snowing me. :)
Click to expand...
Probably on the type of work you do, that's probably mostly true. I don't mind saying that the majority of other work employs more electrical installers who call themselves electricians.
 
ron said:
I have not had the opportunity to use a milliohm meter to check, but I would guess that a properly made-up steel compression coupling will have a lower impedance than a properly made-up set screw coupling. There just seems to be more surface area contact.
Click to expand...
I think that there would be a lot less surface area contact with the compression type as the only direct contact is the two edges of the compression band. With a set screw you have a very solid contact a the screw and on the opposite side where the screw pushes the pipe tightly against the wall of the coupling.
 
don_resqcapt19 said:
I haven't done any commerical in a long time, but the only issue I ever had with set screw couplings is that on a long run they leak too much for a vacuum fish tape system.
Click to expand...

That seems to be more of a problem with steel SS fittings then with diecast SS fittings.
 
I grew up using Regal set screw connectors and couplings. They were the best IMO.

I tried using steel set screw on a house and I hated them. They were a PITA to tighten and they were taller than a die case fitting. Never used them again.

I'm using NEER die cast fittings now.
 
i use whatever connectors we have. i broken a few diecast couplings and connectors. i do like the steel better since there stronger. ive moved a piece of emt and snapped diecast couplings in half
 
Status
Not open for further replies.
Top