360 degree bend rule

[don_resqcapt19]

Smart,

FWIW, RMC couplings have straight threads.

Yes they have straight threads, but are intened to be used with male threads having a taper.

Additionally, there are LFMC connectors with Female NPT threaded hubs (T&B 5271 series, for example).

I was commenting on the drawing you posted, which appears to show a flexible conduit connector threaded into a rigid conduit coupling.
I don't have a link to the article at this time.
Don

 

[Smart $]

I am one who considers a separable connector as access to the conductors, and often pull the wires and then re-assemble the connector, especially with solid wires, as well as using LB's, etc.

However, if the connectors will not be accessible after the installation is complete, you would not be able to discount the bends they represent, and they're harder to pull than elbows.

For example, If I had a 90deg. connector at both ends of a run between boxes, and couldn't access the connectors after the walls are closed, would I be able to pull or re-pull wires?

Chronology aside, I assemble my work in whatever order makes it easiest, quickest, and especially the least harmful to the conductors. Sealtite 90 deg. fittings are the best example.

LFMC 350.42 and LFNC 356.42 both require angle connectors not be used for concealed raceway installations.

IMO this implicitly means LFMC and LFNC angle connectors are considered to be access points for the purpose of installing or removing conductors, while leaving straight connectors somewhat up in the air.

 

[infinity]

I think that UL has recently stated that you can't use flexible conduit connectors with threaded fittings or couplings. They are only intended to be used with enclosures because the connector threads are straight threads and thread fittings and couplings are inteded to be used with conduit threads which have a 3/4" per foot taper.
Don

Then they had better start selling a transition fitting that goes from EMT to FMC. I have yet to see a fitting made for this purpose over 2".

 

[Smart $]

I'd say Bryan is technically correct. Per his suggestion, I took a look at one of the raceway articles, chosen at random. I picked EMT. I found:

358.30 Securing and Supporting. EMT shall be installed as a complete system in accordance with 300.18 and shall be securely fastened in place and supported in accordance with 358.30(A) and (B).

That tells me that they do intend for EMT to be installed as a complete system, EMT from box to box. But there is no prohibition from changing wiring methods after you reach the box.

...and you'll note that there is no similar provision in Articles 350 (LFMC) and 356 (LFNC). Additionally, see my response to Larry in post #22.

...would you pull wire into the run depicted below as it is? ...or would you disconnect the run at 90? sealtite connectors?

I would disconnect the conduit.

Hmmm... I'm going to assume you meant you'd disconnect the sealtite at the straight connector...and if you did, I know you'd also be disconnecting the sealtite at the 90, too! Disconnecting the conduit would be more difficult while not providing any advantages, not to mention an obvious violation

Of those acknowledging the latter, would you change your approach to installing the conductors (not the run) if it is in fact a 300.18(A) violation?

I'd give it serious consideration, but I can't guarantee I would not do the job as you depicted. Sometimes, the real world does create challenges.

Yes, it does!

What say you poll responders... if the conduit depicted above had 360? of bends in the "break" section?

Then I would begin to entertain the notion of getting a box installed at the transistion from EMT to LFMC. That should be our first impulse, IMO.

I can tell you with the highest degree of confidence that will not be the first impulse anytime soon in the industrial world of electrical construction

 

[Smart $]

Then they had better start selling a transition fitting that goes from EMT to FMC. I have yet to see a fitting made for this purpose over 2".

Yeah!

I think anyone making a stipulation like that must have their arse glued to a desk chair.

(Sarcasm) Making the connectors with tapered threads must be too hard

 

[Smart $]

Smart,

Yes they have straight threads, but are intened to be used with male threads having a taper.

That's a hoot!

I'd be willing to bet the author(s) haven't the foggiest clue as to their real intent, and why they have straight threads rather than tapered. I have to wonder if they even know the history of RMC development and usage. IMO, it is a power play. To say certain fittings with straight threads cannot be used with mating straight threads is outright absurd. I can understand to a degree why straight threads should not be mated with tapered threads, but we then have a conflict in terms through everyday contrary usage.

While we're on this topic, would you care to speculate why RE's have straight male threads yet these would not be subject to the same limitations of mating to tapered female threads?

Is that UL statement only regarding LFMC connectors ...or does it also include certain other or any other connector type with straight threads?

 

[Rockyd]

About the RE's, great point. A pipe is just a raceway to protect the conductors within. Wonder how people look at a raceway at times. I have a lot of oil patch time in Alaska, and we use RE's in classified spaces. The concept people need to remember is that the thread purpose is to cool the gasses, by the amount of distance travelled, to less than temp to cause further damage if an explosion happened, inside or outside the pipe. On long vertical drops, I always try to put in a EYD. I also try follow 110.12 as much as possible, not everything is always pretty. On remote jobs, some places look really good in the rearview mirror of a 737!

Pipe is not waterproof, (threaded and glued joints leak) if it were, then underground wouldn't need to be rated for a wet environment.

Biggest concern imaginable would be - does the hardware make up tight so that the conductors won't be damaged during install, and that plant vibration (compressors, crushers, etc0, won't cause damage after install.

 

[iwire]

Another thread that went much further than I would have guessed.

...and you'll note that there is no similar provision in Articles 350 (LFMC) and 356 (LFNC).

We do not need one, 300.18 applies to all raceway installations.

300.1 Scope.
(A) All Wiring Installations. This article covers wiring methods for all wiring installations unless modified by other articles.

I see nothing in 350 or 356 that modifies 300.18

300.18 Raceway Installations.
(A) Complete Runs. Raceways, other than busways or exposed raceways having hinged or removable covers, shall be installed complete between outlet, junction, or splicing points prior to the installation of conductors. Where required to facilitate the installation of utilization equipment, the raceway shall be permitted to be initially installed without a terminating connection at the equipment. Prewired raceway assemblies shall be permitted only where specifically permitted in this Code for the applicable wiring method.

Let me clean that up without changing the meaning


Raceways shall be installed complete between outlet, junction, or splicing points prior to the installation of conductors.

A change over from one raceway to another regardless of it being listed or an angle connector is not a outlet, junction, or splicing point.

I expect some would have a mind to twist this so that a junction is a junction of flex to pipe but that would mean every coupling in any raceway is also a 'junction point' making 300.18(A) worthless.

Where required to facilitate the installation of utilization equipment, the raceway shall be permitted to be initially installed without a terminating connection at the equipment.

This tells us we can forgo the general rule at the equipment termination, not near it, not within sight of it but at the equipment.

This picture from Smart is IMO code complaint, we could pull the 90 apart at the equipment.

This picture from George is not IMO code compliant as he intends to break the 90 away from the equipment.

Of course what I feel the NEC requires and what really happens in the field does not always match up.

Many edits, having trouble with images.

 

[George Stolz]

Where required to facilitate the installation of utilization equipment, the raceway shall be permitted to be initially installed without a terminating connection at the equipment.

This tells us we can forgo the general rule at the equipment termination, not near it, not within sight of it but at the equipment.

That would depend on what each person perceives as "at" the equipment.

If the roofer swung down the ladder and said, "I have four of these boots. I know where three of them go, but I'm not sure of the last one."

If I replied, "It goes at RTU-3," would he glue his boot to the equipment, or to a spot on the roof immediately beside it?

I'm not saying you're wrong, I'm just saying there is more than one way to read this section.

Many edits, having trouble with images.

I know what you mean, I just had an arm-wrestling match with a pair of quotes and lost.

 

[iwire]

[/color]

That would depend on what each person perceives as "at" the equipment.

Honestly George for you that is pretty thin.

Read the whole sentence.

Where required to facilitate the installation of utilization equipment, the raceway shall be permitted to be initially installed without a terminating connection at the equipment.

Notice they say a terminating connection at the equipment.

IMO opinion that clearly means the termination of the raceway into the equipment.

If I try to read it your way this spot could be under the roof deck in your picture as I would still be near the equipment.

 

[George Stolz]

Honestly George for you that is pretty thin.

What, Smart is the only one who gets to play on the thin ice anymore?

 

[iwire]

What, Smart is the only one who gets to play on the thin ice anymore?

I just expect more from you than smoke and mirrors.

 

[George Stolz]

Seriously, though, let's look at this another way:

(A) Complete Runs. Raceways, other than busways or ex-posed raceways having hinged or removable covers, shall be installed complete between outlet, junction, or splicing points prior to the installation of conductors.

Let's say we are reading this from the perspective that this means "any raceway wiring method chosen shall be complete from box to box." As in, if you choose EMT, it will be EMT until it finds a box. If you choose LFMC, then it will be complete from box to box.

Where required to facilitate the installation of utilization equipment, the raceway shall be permitted to be initially installed without a terminating connection at the equipment.

So this sentence, which essentially looks like it amends the first (without being an actual exception), is saying we can install a portion of the raceway, and finish it when the equipment is installed.

It does not say that the equipment/raceway can be installed without ever providing an end for this raceway at a box; it does not say that the last step can be a different wiring method either. These are both interpretations we are imposing on the words.

Really, I can't see the sense in the sentence as it sits. Edit: Raceways are installed one piece at a time, so if a pipe sits uncompleted for a week, is it a code violation until it is complete? What if it is never used at all, and is a pre-wire? It seems to me that the code violation does not exist until we install conductors in the raceway. That is the time (or order) sensitive action.

The only aspect of the first sentence that it seems to affect is the installation of conductors. That is the only order-relevant component of the first sentence:

• Conductors shall be installed after the raceway is complete.
• Where necessary to install the equipment, the order can be overlooked.

I'm thinking out loud, what do you think?

 

[iwire]

what do you think?

I think I am having an aneurism.

 

[don_resqcapt19]

Smart,

While we're on this topic, would you care to speculate why RE's have straight male threads yet these would not be subject to the same limitations of mating to tapered female threads?

I believe that the REs for classified locations have tapered theads and those are the only ones that I use.

Is that UL statement only regarding LFMC connectors ...or does it also include certain other or any other connector type with straight threads?

It applied to all conduit and cable fittings with straight threads.
Don

 

[don_resqcapt19]

I am now sure that the REs that I use have tapered threads. The following is from the Crouse-Hinds Catalog.

RE reducers have:
integral bushing which prevents damage to wires
full, clean cut tapered threads

Don

 

[iwire]

What is an "RE"?

 

[George Stolz]

I think I am having an aneurism.

Not my intention, I assure you. I just don't see anything very solid in this jello of a section.

If we don't knead this around, pound it flat and make something of it, it won't be settled in my head.

Edit to add: I'm wondering what an RE is too.

 

[iwire]

I just don't see anything very solid in this jello of a section. .

Well this is what I don't understand, to me it is as clear as day.

I have no idea how you can read that sentance and arive at the conclusion that you can not change raceway types. (shrug)

Again I will point out that what I see happening in real life and what the NEC requires may not always match up.

 

[roger]

RE = Reducing Bushing.

Roger