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Set screw EMT connectors.

1

10Driver

Member
Location
California
Occupation
Retired
I was told set screw EMT connectors do not meet the 2023 NEC code but I cannot find any specific guidance one way or another. The conduit is inside an aircraft hangar, not being used for ground purposes and is definitely not in a wet location defined by the NEC. Are EMT compression fittings required in this case or do the set screw fittings meet code?
 
1

10Driver

Member
Location
California
Occupation
Retired
infinity said:
Who told you this and what is the basis for that statement?
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The electrician who'll be connecting our solar system to the LINE side at the MCP (and before you say you can connect on the LOAD side, we don't want to derate the MCP). The only thing I can think of is local codes require it (not the NEC).
 
roger

roger

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Fl
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Steel is all I have used for the last 25 years.

I have posted this before but, we were doing a group of new OR's with ISO power systems where the engineer specked set screw fittings which was not the norm so I asked him why he specked them. He said he knew in tight spots or where raceways were located next to each other set screws could be tightened whereas compression may not be. I had said this for years and was surprised an EE actually saw it the same way.
 
E

Eddie702

Licensed Electrician
Location
Western Massachusetts
Occupation
Electrician
They have been used for years don't see any issue with them. I prefer steel though I don't see an issue with die cast. I have seen specs that call for compression only and have seen specs calling for steel set screw. University Of Massachusetts, I think.
 
1

10Driver

Member
Location
California
Occupation
Retired
roger said:
Steel is all I have used for the last 25 years.

I have posted this before but, we were doing a group of new OR's with ISO power systems where the engineer specked set screw fittings which was not the norm so I asked him why he specked them. He said he knew in tight spots or where raceways were located next to each other set screws could be tightened whereas compression may not be. I had said this for years and was surprised an EE actually saw it the same way.
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Other than spec’s requiring it, seems like set screws are the best way to go in tight spaces…
 
infinity

infinity

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New Jersey
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Journeyman Electrician
roger said:
Absolutely and IMO everywhere else. (y)
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I couldn't agree more. Half of the time on large compression fittings they're never fully tightened because you cannot tighten them when they're close together. Steel set screw and an impact gun will ensure that every fitting is tight. Now of only engineers would understand this no one would ever spec compression again over steel set screw.
 
ActionDave

ActionDave

Chief Moderator
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Location
Durango, CO, 10 h 20 min from the winged horses.
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Licensed Electrician
roger said:
Steel is all I have used for the last 25 years.

I have posted this before but, we were doing a group of new OR's with ISO power systems where the engineer specked set screw fittings which was not the norm so I asked him why he specked them. He said he knew in tight spots or where raceways were located next to each other set screws could be tightened whereas compression may not be. I had said this for years and was surprised an EE actually saw it the same way.
Click to expand...
That is a beautiful story worth retelling. How appropriate it should come up during the season when we celebrate miracles.
 
ActionDave

ActionDave

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Location
Durango, CO, 10 h 20 min from the winged horses.
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infinity said:
I couldn't agree more. Half of the time on large compression fittings they're never fully tightened because you cannot tighten them when they're close together. Steel set screw and an impact gun will ensure that every fitting is tight. Now of only engineers would understand this no one would ever spec compression again over steel set screw.
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But they won't. The spec isn't based on anything practical. It is either the engineer making an emotional decision or there is no thought given to the choice, it's just pulled from the electrical chapter of the Big Book Of Specs That We Put In All Our Jobs that has been handed down from father to son for generations.
 
infinity

infinity

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New Jersey
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Journeyman Electrician
ActionDave said:
But they won't. The spec isn't based on anything practical. It is either the engineer making an emotional decision or there is no thought given to the choice, it's just pulled from the electrical chapter of the Big Book Of Specs That We Put In All Our Jobs that has been handed down from father to son for generations.
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Boiler plating is a big problem in this industry. Let's just copy and paste the same stuff we did for decades with no real world statistics to support it. Compression EMT fittings must be something that is taught in engineering school becuase when you inquire about them being part of a spec the common answer it usually "they're better."
 
kwired

kwired

Electron manager
Location
NE Nebraska
Occupation
EC
hbiss said:
Maybe the diecast, but the steel ones don't.

-Hal
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die cast compression is also the cheap way to go.

Though there was period about 20 years ago when zinc prices spiked and it was about same cost either way for a time. I stopped using die cast fittings back then, partly because my favorite ones "Regal fittings" closed the doors on their operation and have almost exclusively used steel fittings ever since.

Regal had excellent threads and locknuts, you had to actually try pretty hard to cross thread them, unlike about any fitting available today that cross threads just looking at it. Though they were supposedly die cast, as good of threads as they had there must have been some machining done after casting to get such a fine product.
 
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