LB Fitting

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Alwayslearningelec

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Sorry I know, dumb question. When using EMT w/ cvompression fittings how would you attach LB to stick of conduit? It says set screw.

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Good question so others can learn. Some LBs have SS on hub, others have FM threads to use with EMT connector,
But IDK about cost, I used and see mostly the FM thread type
 
tom baker said:
Good question so others can learn. Some LBs have SS on hub, others have FM threads to use with EMT connector,
But IDK about cost, I used and see mostly the FM thread type
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Ok, interesting and thanks. What is used more often when having to use compression fittings? Would they allow you to use one with set screws if compression fitting were specified?

If the LB had female threads would a standard compression connector like this be used?

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Alwayslearningelec said:
How have you done it most jobs? Set screw LB or comp connector?

Why a volation? Connector not listed to be used with LB?
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LB's exist that are basically combos; they have threads for use with RMC and threaded fittings (stupid listing issues be damned), as well as set screws that allow you to just install it on the end of a piece of EMT. Home Depot is selling these "combo" style LBs, probably so they can stock fewer part numbers.

Note that the setscrew method only works for dry locations. I tend to use fittings in the LB either way, as I think jamming the EMT into the end of the LB look hacky.


SceneryDriver
 
infinity said:
Yup. We use them anyway. No one really cares if you screw a compression connector into a conduit body. We always use set screw fittings unless forced to use compression.
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So you've used LB's with set screw on a EMT conduit run with compression couplings?
 
Alwayslearningelec said:
How have you done it most jobs? Set screw LB or comp connector?

Why a volation? Connector not listed to be used with LB?
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While used everyday without issue, it is a listing and evaluation issue. The following is from the UL Guide Information for "Conduit Fittings (DWTT)".
Fittings with internal female threads (e.g., hubs, conduit bodies, couplings) have only been investigated for use with threaded rigid conduit.

Male fittings not provided with a locknut, intended for securement to a threaded hub, are marked on the smallest unit shipping carton, "For securement to a threaded hub only," or the equivalent.

Male fittings provided with a locknut, also intended for securement to boxes with threaded entries, hubs or fittings with internal female threads (e.g., conduit bodies, couplings), are marked on the smallest unit shipping carton, "For securement to a threaded hub," or the equivalent.
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Note that the second two statements are in conflict with the first statement.
 
don_resqcapt19 said:
Note that the second two statements are in conflict with the first statement.
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Not really. The distinction is with respect to who does the investigation.

If the box says "For securement to a threaded hub" then you can screw the fitting into any fitting with female internal threads. The responsibility is on the male fitting manufacturer to design the male fitting accordingly; the female fitting manufacturer only has to design for connection to threaded rigid conduit.

Cheers, Wayne
 
I work in the natural gas industry

We always threaded LMFC connectors into fittings, all sort of transmitters and devices.

The only trouble we have had with inspectors is some guys will leave the lock ring on the connector to get it to tighten up in a certain spot and people have argued that with that they don’t have the correct amount of threads in.
 
What else are you supposed to do? EMT is allowed in a wet location or on a roof for example. I don't see how and EMT job can be considered "raintight" if you use the set screws. I always use compression connectors and couplings with threaded fittings.

I always take the locknuts off when putting a connector into an LB looks like a hack job to me if you leave them on.
 
infinity said:
This entire argument is silly and should be resolved. This is a common installation practice and I've never seen any real world data to say that it's unsafe.
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It's not unsafe. It's an on-paper-only listing issue.

It's just that no one wants to pay the overlords at UL an obscene amount of money to say "yep, what everyone has been doing for decades is perfectly fine, just like everyone else already knows."


SceneryDriver
 
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