LFMC into a RGS coupling under 2”?

[Isaiah]

Our inspector is telling us you can’t connect LFMC directly into a rigid galvanized steel coupling unless it’s 2” or larger. Has anyone heard of this?


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[infinity]

He's probably referring the the straight threads on the connector. Do they actually make fitting for this I don't think so.

 

[Isaiah]

He's probably referring the the straight threads on the connector. Do they actually make fitting for this I don't think so.

I think you’re right - so how would you connect the LFMC with into the rigid run?


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[electrofelon]

That is no such rule. Some fittings are not made or hard to get in over 2" so maybe that's how he came up with that, but a LFMC to RMC appears to be available in all sizes. For example Appleton ST-300F is a 3"

 

[Isaiah]

That is no such rule. Some fittings are not made or hard to get in over 2" so maybe that's how he came up with that, but a LFMC to RMC appears to be available in all sizes. For example Appleton ST-300F is a 3"

I believe you’re right on this thanks


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[Eddie702]

We always used couplings and never had an inspector call us on this I think this is a ridiculous rule

 

[electrofelon]

We always used couplings and never had an inspector call us on this I think this is a ridiculous rule

Yeah I have never been called on this type of thing, but it's always looming there in the background. I wish the industry would fix this. All the NFPA has to do is put an exception in to not require following the instructions/listing for screwing fittings into hubs and couplings, but of course they won't, no time, busy making up dumb code rules.

 

[Isaiah]

We always used couplings and never had an inspector call us on this I think this is a ridiculous rule

I agree also. But I didn’t want to say anything directly to the inspector until I checked with the gurus on the forum


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[Isaiah]

Yeah I have never been called on this type of thing, but it's always looming there in the background. I wish the industry would fix this. All the NFPA has to do is put an exception in to not require following the instructions/listing for screwing fittings into hubs and couplings, but of course they won't, no time, busy making up dumb code rules.

So basically you’re saying the connection from the RGS to the LFMC connector, both have to be Listed, correct?


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[electrofelon]

So basically you’re saying the connection from the RGS to the LFMC connector, both have to be Listed, correct?


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I think you would have to dig into the instructions and listing on the LFMC connector. Maybe the UL white book has something to say about it? IIRC there's something about they've only been evaluated for mating to cabinets and have not been evaluated on hubs.

 

[don_resqcapt19]

I think you would have to dig into the instructions and listing on the LFMC connector. Maybe the UL white book has something to say about it? IIRC there's something about they've only been evaluated for mating to cabinets and have not been evaluated on hubs.

The UL Guide Information for Conduit Fittings (DWTT) says:

Male threaded fittings provided with or without a locknut and intended for securement to boxes with threaded entries or fittings with internal female threads (e.g., hubs, conduit bodies, couplings) are provided on the smallest unit shipping carton with installation guidance to install into a box with a threaded entry or hub.

 

[electrofelon]

The UL Guide Information for Conduit Fittings (DWTT) says:

Thanks Don.....now what exactly does that mean?

 

[don_resqcapt19]

Thanks Don.....now what exactly does that mean?

It means unless the box the connector came in is marked to say you can use that connector with fittings having female threads, you can't.

No one follows this. At least 95% of the LFMC connectors we installed were screwed into fittings having female threads.

 

[Isaiah]

It means unless the box the connector came in is marked to say you can use that connector with fittings having female threads, you can't.

No one follows this. At least 95% of the LFMC connectors we installed were screwed into fittings having female threads.

Don we have many LFMC straight male connectors screwed directly into RGS couplings, Tee and LB condulets. This should be no problem, right?


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[don_resqcapt19]

Don we have many LFMC straight male connectors screwed directly into RGS couplings, Tee and LB condulets. This should be no problem, right?


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None other than a very picky inspector. As I said that is how the vast majority of the ones my guys used were installed. I think that is the case for every industrial plant that uses LFMC.

 

[wwhitney]

FWIW, UL 514B "Conduit, Tubing, and Cable Fittings" permits, but does not require, performing the resistance test on a connector by using a threaded coupling rather than using a box or metal plate, per Clause 8.9.

So the UL standard, at least, sees putting a connector into a coupling as equivalent to putting it through a knockout and using the supplied locknut, at least as far as providing a sufficiently low impedance ground fault path.

Cheers, Wayne

 

[Isaiah]

FWIW, UL 514B "Conduit, Tubing, and Cable Fittings" permits, but does not require, performing the resistance test on a connector by using a threaded coupling rather than using a box or metal plate, per Clause 8.9.

So the UL standard, at least, sees putting a connector into a coupling as equivalent to putting it through a knockout and using the supplied locknut, at least as far as providing a sufficiently low impedance ground fault path.

Cheers, Wayne

Thanks Don and Wayne
What we have is very picky inspector
I will try to convince him using this feedback!


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