350.26 discusses the 360 bend rule for sealtite. My question is as follows. If there are 4 hardpiped 90 degree bends are the sealtite bends applicable if you pull the cable with the sealtite off? When completed it looks like 6 90 degree bends but the pull is 4 90's then slip the sealtite on and bring it in the seatite connection. I believe there is no stress to the wire but I don't see exceptions to allow this.
360 degree bend rule
- Thread starter Klekot
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bphgravity
Senior Member
- Location
- Florida
The installation you describe is in violation of 300.18(A) of the NEC. And the applicable raceway section.
allenwayne
Senior Member
I did a home where the pool feed as required by the AHJ be within pipe this was several years ago.The design of the home didn`t allow to many straight runs and the inspector said more than 360 degrees of bends.Although they were sweeping bends in pipe no 90`s there was still more than 360 degrees of bends and had to redo it.
What about the following section for Exception for 300.18A? Short sections of raceways used to contain conductors or cable assemblies for protection from physical damage shall not be required to be installed complete between outlet, junction, or splicing points.
I don't really care either way I just want to make sure it's all done right in the future.
Thanks
I don't really care either way I just want to make sure it's all done right in the future.
Thanks
I disagree with your interpretation. 300.18(A) says, "Raceways... shall be installled complete... prior to the installation of conductors." However, it does not say the complete run cannot be disconnected and reconnected as part of the conductor installation process.bphgravity said:
Let's take an informal poll: Of those that have substantial experience, would you pull wire into the run depicted below as it is? ...or would you disconnect the run at 90? sealtite connectors? 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?
View attachment 256
As to the sealtite bends counting towards the 360?, I believe it also falls unto similar considerations. I agree with the OP. What say you poll responders... if the conduit depicted above had 360? of bends in the "break" section?
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Bob NH
Senior Member
- Location
- The "Live Free or Die" State
If I had a problem like that I would put in a Type C straight through conduit body at some point where it would make the total not exceed 360 degrees in either direction. In the case described in the original post, the inspector would come back and find the conduit body at the junction between the sealtite and the hard pipe.
Yes, that is what would have to be done to make the installation code compliant. But for the sake of conversation, let's discuss it from the standpoint of premise rather than compliance...Bob NH said:
Anyone having substantial experience with pulling wire through sealtite knows it is practically a given the run is going to be disconnected at the 90? connectors. While the run is disconnected, and given the flexible nature of sealtite, there is essentially no difference in pulling through the sealtite at both ends than pulling into and out of C-fittings at the transitions.
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- Location
- New Jersey
- Occupation
- Journeyman Electrician
Bob NH said:
C condulets are fine with small conductors but most can't meet the required 8X the conduit size for large conduits. For this reason many larger conduit bodies will not help satisfy the 360 degree rule. You could put 5-500kcmil THHN conductors in a 3" EMT but a 3" C condulet would most likely allow a maximum conductor size that is much smaller than the conduit fill would allow.
- Location
- Massachusetts
Smart $ said:
I did not see anyone say there are any 90? connectors involved in the run.
I took the OP to mean there are 90? turns (or a total of 90?s) in the LFMC itself.
C condulets are fine with small conductors but most can't meet the required 8X the conduit size for large conduits. For this reason many larger conduit bodies will not help satisfy the 360 degree rule. You could put 5-500kcmil THHN conductors in a 3" EMT but a 3" C condulet would most likely allow a maximum conductor size that is much smaller than the conduit fill would allow.
Number four, or more, have their own rules starting at 314.28, Six, and the mix, are not subject to the 8X.
Four's and more, done without 314.28 applied are can be a code violation unless one pays attention to the exception. Even then, it's a good idea to look in a fitting for "max wire" 314.28 (A) (3) capacity.
Wire space gets paid attention to in classified spaces too 501.15 (C) (6) also. This industrial standard of 25% fill in seal offs took the hate out of packing.
According to the pix attached, it's a civilized, quality looking install. Sell it.
edit - spelling
Number four, or more, have their own rules starting at 314.28, Six, and the mix, are not subject to the 8X.
Four's and more, done without 314.28 applied are can be a code violation unless one pays attention to the exception. Even then, it's a good idea to look in a fitting for "max wire" 314.28 (A) (3) capacity.
Wire space gets paid attention to in classified spaces too 501.15 (C) (6) also. This industrial standard of 25% fill in seal offs took the hate out of packing.
According to the pix attached, it's a civilized, quality looking install. Sell it.
edit - spelling
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- Location
- Massachusetts
Rockyd said:
I agree....if the picture Smart provided accurately represents what klekot is describing.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Hospital Master Electrician
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:Smart $ said:
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.
I would disconnect the conduit.Smart $ said:
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.Smart $ said:
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.Smart $ said:
- Location
- Windsor, CO NEC: 2017
- Occupation
- Hospital Master Electrician
Would you say that it's applicable in this case? Is the LFMC being used for cover of another wiring method in need of extra physical protection for a short distance, or is it being used as a replacement for a less flexible raceway?Klekot said:
I wouldn't say the scenario matches the exception, IMO.
- Location
- Windsor, CO NEC: 2017
- Occupation
- Hospital Master Electrician
Here's am example that came up lately for me.georgestolz said:Sometimes, the real world does create challenges.
In the building I'm currently working on, there are a few Roof Top Units. Common practice in my area is to stub EMT through the roof, allow the roofers to install boots over them, and then transistion to LFMC to get to the equipment.
With this new perspective, I would need to changeover to LFMC at a box. So, the easiest way to do that would be the joists below the roof. The problem is, LFMC is not rigid enough to use in the roofer's boots, so I would compromise the roof if I were to do that.
FWIW, I've never heard of an installation failing for transistioning from one wiring method to another.
Recently, in an ECM issue, Joe Tedesco highlighted a EMT-to-FMC changeover that was very professionally done, IMO. There have been many members here that have mentioned the practice in various applications.
I do not see the safety hazard in the practice.
georgestolz said:
I agree. It is my opinion that the 360 degree rule would only apply in the portion of the run that is un accessable to pulling after installation. IMO, it is resonable to expect that you would pull the conductors then connect to the final unit if it is free standing or a seperate compartment that you would service or replace over time, such as an A/C unit
- Location
- Illinois
- Occupation
- retired electrician
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
Don
- Location
- Massachusetts
georgestolz said:
EMT?
Might be a difference in weather conditions, here job specs (and IMO good practice) require RMC to be used here.
BTW, most modern RTUs can be supplied without a separate roof penetration. You can come up inside the unit from inside the building without entering the duct work.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
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.
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.
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