# EMT Conduit inside walls and throught the house



## tk3000 (Dec 16, 2015)

Sometime ago I talked about deploy emt conduit throughout the house and inside walls as risers going up to the ceiling and attic. It is my understanding that the the romex is not going to be inside a conduit 100% of the time, one can fill it up to 100% (100% filling rate). Using romex gives the flexibility of transition from conduit to no-conduit situations(small segments, unpractical situations for conduit, etc).  In some situations, specially whereas 3 wires are required in a 20 amps circuits and plus which will travel inside conduit all the time, I will likely use THHN wires (especially because I don't intend to use ¾ emt conduit). 

Using the emt as a riser from an outlet box inside walls I plan to use the following configuration: 







by which instead of bending the conduit in the attic (which would a nightmare), once the conduit enters the attic through the joist it will connected to a junction box right away.

The following the pic shows from behind a conduit connected to a future outlet box in the kitchen area with an emt rising to the ceiling. And since it is inside the emt conduit which is affixed to the box, I was wondering whether or not the requirement for straps/clamps are. I heard that in some situations the requirement would be: position straps within 3 ft. of each box and within 10 ft. thereafter. Also, since the knockout in the box and the hole above in the ceiling are well aligned, there were no need to offset the conduit; but the emt conduit are not making direct contact with the stud which then would make it difficult to use straps in this case. 







In the basement, I am also using conduit 95% of the time, as shown below: 







There is a situation whereby the nm-b exist the "wall" throught a hole directly to a box (which will have a switch and outlet) through its back (back knockout hole) but then there is not room for a fitting (which does not seem necessary due to the fact that the hole in the wall is much smaller than the knockout , but in any case I used an anti-short bushing to protect it. Would that be ok codewise? I was wondering whether or not these small plastic anti-short bushings are required or not (it seems prudent to use them, specially with bx/mc conduit)






thks!


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## slownsteady (Dec 16, 2015)

The setup looks pretty impressive, but I have to ask "Why bother?" There are gazillions of miles of romex running through the walls of houses all over North America with a very low percentage of problems.


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## Sparky617 (Dec 16, 2015)

slownsteady said:


> The setup looks pretty impressive, but I have to ask "Why bother?" There are gazillions of miles of romex running through the walls of houses all over North America with a very low percentage of problems.



Not in Chicago though.  If not required to run conduit, I'd use Romex.  A couple of runs from the basement to the attic for future needs isn't a bad idea.  I have two runs in my house, still unused after 16 years but they're there if I need them.  With WiFi becoming so widespread, and I have two WiFi routers in my house to give great coverage throughout I may never need these runs.


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## slownsteady (Dec 16, 2015)

So, Chicago requires conduit in the walls?


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## Snoonyb (Dec 16, 2015)

slownsteady said:


> So, Chicago requires conduit in the walls?



Can anybody say, UNION!


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## Snoonyb (Dec 16, 2015)

tk3000 said:


> Sometime ago I talked about deploy emt conduit throughout the house and inside walls as risers going up to the ceiling and attic. It is my understanding that the the romex is not going to be inside a conduit 100% of the time, one can fill it up to 100% (100% filling rate). Using romex gives the flexibility of transition from conduit to no-conduit situations(small segments, unpractical situations for conduit, etc).  In some situations, specially whereas 3 wires are required in a 20 amps circuits and plus which will travel inside conduit all the time, I will likely use THHN wires (especially because I don't intend to use ¾ emt conduit).
> 
> Using the emt as a riser from an outlet box inside walls I plan to use the following configuration:
> 
> ...



Whats the general motivation in selecting EMT?


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## Sparky617 (Dec 17, 2015)

Snoonyb said:


> Can anybody say, UNION!



I think the motivation was fire code after the great Chicago fire.  But, millions of homes in the USA have had Romex since the post WW2 building boom.  I don't live in the Chicago area but I believe even in single family construction the requirement is still for EMT.

But yes it is a great tool for keeping union electricians employed and skilled DIYers out of doing home improvements.


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## Snoonyb (Dec 17, 2015)

Sparky617 said:


> I think the motivation was fire code after the great Chicago fire.  But, millions of homes in the USA have had Romex since the post WW2 building boom.  I don't live in the Chicago area but I believe even in single family construction the requirement is still for EMT.



An acquaintance, who works here on the truly left coast in the winter, from Chicago, confirms that.

There are a couple additional union based restrictions, which have been overcome, and they are the slot-head screw and the bond bushing for grnd.



Sparky617 said:


> But yes it is a great tool for keeping union electricians employed and skilled DIYers out of doing home improvements.



Occasionally in older homes we will find iron pipe for switch legs.


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## slownsteady (Dec 17, 2015)

Ah yes, the Chicago fire. of course! We don't want any cows kicking over the romex.


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## CallMeVilla (Dec 17, 2015)

Odd to see this .... conduit is such a pain for bending  ....  why not use MC which is flexible, fast, and meets commercial code too?


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## tk3000 (Dec 18, 2015)

CallMeVilla said:


> Odd to see this .... conduit is such a pain for bending  ....  why not use MC which is flexible, fast, and meets commercial code too?



There is some  MC conduit+wire that was installed in the house when they upgrade the water heater to an electric  one at some (since it seems much newer than the majority of the electrical installation), I probably will keep it and expand on it a little. But then MC is more expensive and probably not a good choice for upgrading  (or running additional) wires in the future. It is not   only electrical wires, but the conduit could also be used to run low voltage wires  for sensors, cameras, etc. 

By the way, the MC  wire likely installed in the last 5 years present at the house was hooked up to a junction box without any fitting and the MC wire seems to prone to have very rough ends. Below is a pic of the a mc wire end that goes to an j-box that found, and all the wires coming out of it are damaged due to its rough ends. I will cut off the bad part, and use anti-shorts: 






Yeah, I know it is pain to bend, measure, etc; but no pain = no reward


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## Snoonyb (Dec 18, 2015)

tk3000 said:


> There is some  MC conduit+wire that was installed in the house when they upgrade the water heater to an electric  one at some (since it seems much newer than the majority of the electrical installation), I probably will keep it and expand on it a little. But then MC is more expensive and probably not a good choice for upgrading  (or running additional) wires in the future. It is not   only electrical wires, but the conduit could also be used to run low voltage wires  for sensors, cameras, etc.
> 
> By the way, the MC  wire likely installed in the last 5 years present at the house was hooked up to a junction box without any fitting and the MC wire seems to prone to have very rough ends. Below is a pic of the a mc wire end that goes to an j-box that found, and all the wires coming out of it are damaged due to its rough ends. I will cut off the bad part, and use anti-shorts:
> 
> ...



So, you are not concerned about cross-talk between your HV and LV, in the same conduit?

The original metallic wrapped was called bx and it was common practice to wrap the conductors at the exit points with friction tape.

I always had the thought that the industry had gotten ahead of itself, with bx, and It's taken some time to catch up.


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## tk3000 (Dec 18, 2015)

Snoonyb said:


> So, you are not concerned about cross-talk between your HV and
> LV, in the same conduit?
> 
> The original metallic wrapped was called bx and it was common practice to wrap the conductors at the exit points with friction tape.
> ...



There will be a separate conduit for high speed bandwidth in order to avoid cross talk. Now the bitstream of data going to/from the sensors would likely use OneWire  protocol and would not suffer from any magnetic field due to be way too simple and with tiny small amount of data flow. In practice most basic video stream does not seem to suffer either (but that is another story), but it is mostly for sensors anyways (tons of them)


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## CallMeVilla (Dec 18, 2015)

tk3000 said:


> .By the way, the MC  wire likely installed in the last 5 years present at the house was hooked up to a junction box without any fitting and the MC wire seems to prone to have very rough ends. Below is a pic of the a mc wire end that goes to an j-box that found, and all the wires coming out of it are damaged due to its rough ends. I will cut off the bad part, and use anti-shorts:



ALWAYS use anti-shorts .... required by code and just makes common sense.

:


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## Snoonyb (Dec 18, 2015)

tk3000 said:


> There will be a separate conduit for high speed bandwidth in order to avoid cross talk. Now the bitstream of data going to/from the sensors would likely use OneWire  protocol and would not suffer from any magnetic field due to be way too simple and with tiny small amount of data flow. In practice most basic video stream does not seem to suffer either (but that is another story), but it is mostly for sensors anyways (tons of them)



OK. Back to the original question; Blocking, both vertical and horizontal will afford the attachment locations.

The original octagon box you replaced with a square box had a connector preventing the romex be pulled out of it. Just an isolation bushing corrupts that and the romex can be pulled out. Romex is required to be attached at all box entry points.


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## slownsteady (Dec 18, 2015)

About that square box (now that we finished talking about why conduit): The bushing does nothing that a quick scrape with sandpaper wouldn't fix. BUT; if the whole purpose of a jbox is to contain any 'hot spots' that may occur, then that little bit of wood behind the box should be protected. No? Kind of defeats the purpose of all that nice metal conduit.....


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## tk3000 (Dec 19, 2015)

slownsteady said:


> About that square box (now that we finished talking about why conduit): The bushing does nothing that a quick scrape with sandpaper wouldn't fix. BUT; if the whole purpose of a jbox is to contain any 'hot spots' that may occur, then that little bit of wood behind the box should be protected. No? Kind of defeats the purpose of all that nice metal conduit.....



I realize that the wood does not represent any roughs  surface likely to mar the nm-b sheathing, I did not that just for consistency (everything has bushings/fittings).

Only because a small section of the romex is exposed (made clear since the beginning that 95% of the romex would be protected in the basement, there are 5% that may not be), does that defies the purpose of having the vast majority of the romex  protected and upgrading/updating ready? Is this irony or something?


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## tk3000 (Dec 19, 2015)

Snoonyb said:


> OK. Back to the original question; Blocking, both vertical and horizontal will afford the attachment locations.
> 
> The original octagon box you replaced with a square box had a connector preventing the romex be pulled out of it. Just an isolation bushing corrupts that and the romex can be pulled out. Romex is required to be attached at all box entry points.



The original box did not have a retaining fitting at the back of the octagonal j-box (it had on both sides though).  There is no big deal installing a retaining fitting in the back of the box, but I would have to bore a partial hole on the  wall/joist; anyhow  in this situation the romex comes  from the back of a wall cavity and thus it would be very difficult for someone to pull it out (even at the other end of the wire: the other jbox is located on the other side of the wall, so this very small segment [maybe 2 feet] of  romex is basically travelling between two sides of the same wall). But I can  always bore a partial hole and add a retaining fitting if  is required.


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## Snoonyb (Dec 19, 2015)

tk3000 said:


> The original box did not have a retaining fitting at the back of the octagonal j-box (it had on both sides though).  There is no big deal installing a retaining fitting in the back of the box, but I would have to bore a partial hole on the  wall/joist; anyhow  in this situation the romex comes  from the back of a wall cavity and thus it would be very difficult for someone to pull it out (even at the other end of the wire: the other jbox is located on the other side of the wall, so this very small segment [maybe 2 feet] of  romex is basically travelling between two sides of the same wall). But I can  always bore a partial hole and add a retaining fitting if  is required.



Ok. But if someone were to remove that box on the other side, they could then pull the romex to the limits defined by the connection within, not the romex connector required.

Building codes are designed to protect you, from you.


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## slownsteady (Dec 19, 2015)

> Only because a small section of the romex is exposed (made clear since the beginning that 95% of the romex would be protected in the basement, there are 5% that may not be), does that defies the purpose of having the vast majority of the romex protected and upgrading/updating ready? Is this irony or something?



I was more interested in pointing out that the wood is exposed to the inside of the jbox.


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## tk3000 (Dec 20, 2015)

Snoonyb said:


> Ok. But if someone were to remove that box on the other side, they could then pull the romex to the limits defined by the connection within, not the romex connector required.
> 
> Building codes are designed to protect you, from you.



First off, this is a work in progress; and this the very first stage of the install and by no means final (more of a preliminary). Code is the is the  minimum bar to avoid very sloppy jobs. One could also pull the romex from a inside a  conduit, and there is no retaining  fitting with the use of the conduit; so some psycho could simply pull all the wires from the conduits from its ends. Non-sensical argument indeed. Far more relevant to protect the physical wiring throughout its routes. 

One can only imagine that the retaining fitting is needed due to the fact that all extension wire are not in conduit 99% of the time and thus so much of each extension is exposed to hands and pulling hands all over the place. I have to check with the code to make that such a small section of romex travelling between the two side of the same wall require this retaining fitting since there are lots of exceptions in code for rules that otherwise would be clearly redundant and disconnected from reality

Nonetheless, more protection is always better; even in such a marginal way; and it only takes 5 minutes to bore a partial hole in order to add the retaining fitting


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## Snoonyb (Dec 20, 2015)

tk3000 said:


> First off, this is a work in progress; and this the very first stage of the install and by no means final (more of a preliminary). Code is the is the  minimum bar to avoid very sloppy jobs.



The quality of the performance is the provenance of its provider, not the building code.



tk3000 said:


> One could also pull the romex from a inside a  conduit, and there is no retaining  fitting with the use of the conduit; so some psycho could simply pull all the wires from the conduits from its ends. Non-sensical argument indeed.



Before the conductors are properly connected, after was addressed.



tk3000 said:


> Far more relevant to protect the physical wiring throughout its route.



Your time, your money. 



tk3000 said:


> One can only imagine that the retaining fitting is needed due to the fact that all extension wire are not in conduit 99% of the time and thus so much of each extension is exposed to hands and pulling hands all over the place.



Until the conductors are secured, connected and the walls covered. 



tk3000 said:


> I have to check with the code to make that such a small section of romex travelling between the two side of the same wall require this retaining fitting since there are lots of exceptions in code for rules that otherwise would be clearly redundant and disconnected from reality.



Please be so kind as to publish those "exceptions".



tk3000 said:


> Nonetheless, more protection is always better; even in such a marginal way; and it only takes 5 minutes to bore a partial hole in order to add the retaining fitting



Did you not ask for an opinion?


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## tk3000 (Dec 20, 2015)

Snoonyb said:


> The quality of the performance is the provenance of its provider, not the building code.
> 
> 
> 
> ...



Well, about 12 inches of the wire protrudes from inside an electrical box. It seem very easy to pull from any conduit then. By walls, you mean sheetrock == powder + paper which does not entail much protection. I never said that these particular exception exist, but then there are plenty of exceptions within code for many rules (it must stand for a reason that  the NEC has 100s of pages). Maybe this rules was created mainly to avoid wire theft or to offer a sense protection to romex wiring which is inheritingly unsafe (Rodents cause 8% of all house & building fires in the USA). Yeah, I asked for an opinion; but not sarcasm.


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## Kabris (Dec 20, 2015)

EMT will offer the greatest protection if rodents are a major issue in your area, that is correct. An electrical contractor will charge a ton for it, though, if somebody wants it through their entire house, because of how time extensive it is. Material will also cost more due to all of the fittings and THHN, maybe not significantly more, but more nonetheless. It's a sad thing to say, but residential contractors look to get in and out as quickly and cheaply as possible, and romex has ruled the market because of it.  Getting back to your issue with rodents, if the spaces are open and the runs are fairly straight, yeah use EMT to get into the attic or crawl space. It won't take that much longer to rough in. For old work that requires fishing, or for crawl spaces and attics, I would say to use MC, because it has the flexibility to pull and the armored jacket for protection. If rodents are chewing through that, then there's a bigger problem that needs to be taken care of.


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## tk3000 (Jan 2, 2016)

Kabris said:


> EMT will offer the greatest protection if rodents are a major issue in your area, that is correct. An electrical contractor will charge a ton for it, though, if somebody wants it through their entire house, because of how time extensive it is. Material will also cost more due to all of the fittings and THHN, maybe not significantly more, but more nonetheless. It's a sad thing to say, but residential contractors look to get in and out as quickly and cheaply as possible, and romex has ruled the market because of it.  Getting back to your issue with rodents, if the spaces are open and the runs are fairly straight, yeah use EMT to get into the attic or crawl space. It won't take that much longer to rough in. For old work that requires fishing, or for crawl spaces and attics, I would say to use MC, because it has the flexibility to pull and the armored jacket for protection. If rodents are chewing through that, then there's a bigger problem that needs to be taken care of.



Yeah, it would be an expensive proposition in case I would hire an electrician to get this job done. 

The thing is that I have replace so many things (walls, wall bottom plates, studs, etc) that it simply make sense to get the electrical part done best possible way. I don't have a big problem with rodents, but they can very good at hiding and be unnoticed for years to come. 

Yep, I plan on using MC in some areas. Sure enough, using fitting with EMT can be add up very quickly; and that is why I plan on doing mostly offset bends, saddle bends, and bends in general whenever possible with a bending bar. T

The pace of the work is slow because I try to learn as much as possible and often I am away travelling elsewhere. 

thks!


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## Rockrz (Jan 19, 2016)

Snoonyb said:


> Can anybody say, UNION!



Is that like code for... the mob?

Do they whack a brutha for not using conduit? :help:


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## Snoonyb (Jan 19, 2016)

Rockrz said:


> Is that like code for... the mob?
> 
> Do they whack a brutha for not using conduit? :help:



In Chicago, and "while."


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## Rockrz (Jan 19, 2016)

You mean "while in Chicago" ?


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## Snoonyb (Jan 19, 2016)

While in Chicago, while using conduit.


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## Rockrz (Jan 19, 2016)

Snoonyb said:


> While in Chicago, while using conduit.



... the mob will whack ya if you don't use conduit???


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## Snoonyb (Jan 19, 2016)

Not the mob, rombo "dead fish," the mayor.


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## Rockrz (Jan 19, 2016)

OK, I thought the Gambino crime family had moved to Chicago er something...


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## Snoonyb (Jan 19, 2016)

Nope, just the dismalcrates, earning the title of the murder capitol of the U.S.


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## tk3000 (Mar 3, 2016)

Before this thread derailed into politics and whatnot it was about a small section or romex wire without mean of affixing it to the joist and electrical box. 

As a retrospective, I understand that romex is required to be affixed/clamped 12" from a box and also in the box's knockout. I have a situation whereby the romex travels a very short distance (about 4 feet) inside a partial wall which then makes it very difficult to clamp the wire at the box end or inside the wall cavity. The pic below depicts the situation:

















The box below will contain a light switch and a dual receptacle, and the romex come from inside the wood joist and unless I drill a large bore there and then use something low profile as plastic snap-in connectors (http://www.amazon.com/dp/B003BG2I9Q/?tag=skimlinks_replacement-20) I don't see how to clamp the wire to the box itself:


It turns out the NEC provide an exception to theses scenarios. An exception present on NEC 334.30(B) [see below exception]

334.30 Securing and Supporting Nonmetallic-sheathed cable shall be supported and secured by staples, cable ties, straps, hangers, or similar &#64257;ttings designed and installed so as not to damage the cable, at intervals not exceeding 1.4 m (4 1&#8260;2 ft) and within 300 mm (12 in.) of every outlet box. junction box, cabinet, or &#64257;tting. Flat cables shall not be stapled on edge. Sections of cable protected from physical damage by raceway shall not be required to be secured within the raceway.
(A) Horizontal Runs Through Holes and Notches. In other than vertical runs, cables installed in accordance with 300.4 shall be considered to be supported and secured where such support does not exceed 1.4-m (4 1&#8260;2-ft) intervals and the nonmetallic-sheathed cable is securely fastened in place by an approved means within 300 mm (12 in.) of each box, cabinet, conduit body, or other nonmetallicsheathed cable termination.
FPN: See 314.17(C) for support where nonmetallic boxes are used
(B) Unsupported Cables. Nonmetallic-sheathed cable shall be permitted to be unsupported where the cable:
(1) Is &#64257;shed between access points through concealed spaces in &#64257;nished buildings or structures and supporting is impracticable.
(2) Is not more than 1.4 m (4 1 &#8260;2 ft) from the last point of cable support to the point of connection to a luminaire or other piece of electrical equipment and the cable and point of connection are within an accessible ceiling


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## KULTULZ (Mar 4, 2016)

> ...the romex come from inside the wood joist and unless I drill a large  bore there and then use something low profile as plastic snap-in  connectors (http://www.amazon.com/Arlington-Indu.../dp/B003BG2I9Q)
> 
> I don't see how to clamp the wire to the box itself



That is how I would do it. The cable will then be protected from any possible contact with the box opening (sharp).

NEC gave you an out regarding securing the cable inside the wall (new work).

Be sure to ground the box.


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## slownsteady (Mar 8, 2016)

sounds like a happy ending to this thread.


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