# Placing Conduits in Slab



## bradal (Jan 12, 2019)

Hey guys,

Just wondering what everyone has done in the past for running conduits in the slab. On a recent job I have completed the layout and also involved in running the actual conduits on site. I have attached a couple pictures for an idea. What have you done in the past for going through grade beams, stubbing up multiple pipes in one location etc.

I guess I can't post pictures until I have 20 posts. Stupid rule.


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## frenchelectrican (Mar 15, 2007)

If you are a legit electrician then please fill the profile as I posted the link below .,,

http://www.electriciantalk.com/f3/attention-new-members-required-profile-fields-258186/


And also with 20 posting requirement is set up few years back to prevent abuse so post away to get the counts up.

as you are aware with conduit in slab you should be using PVC not the emt conduit if buried in the cement.


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## CoolWill (Jan 5, 2019)

frenchelectrican said:


> If you are a legit electrician then please fill the profile as I posted the link below .,,
> 
> http://www.electriciantalk.com/f3/attention-new-members-required-profile-fields-258186/
> 
> ...



EMT is allowed in concrete.


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## frenchelectrican (Mar 15, 2007)

CoolWill said:


> EMT is allowed in concrete.


I am aware but it will not last very long at all.,,


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## Wirenuting (Sep 12, 2010)

......


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## eddy current (Feb 28, 2009)

frenchelectrican said:


> I am aware but it will not last very long at all.,,


Also, so much faster to install Plastic and just strap it with tie wire. The boxes and fittings are also much faster to install and last longer.

Have not seen EMT getting installed in a slab for many years


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## eddy current (Feb 28, 2009)

bradal said:


> Hey guys,
> 
> Just wondering what everyone has done in the past for running conduits in the slab. On a recent job I have completed the layout and also involved in running the actual conduits on site. I have attached a couple pictures for an idea. What have you done in the past for going through grade beams, stubbing up multiple pipes in one location etc.
> 
> I guess I can't post pictures until I have 20 posts. Stupid rule.


Use wood to make a form for your stubs for accuracy.


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## CoolWill (Jan 5, 2019)

I am just pointing out the fact that EMT is still allowed in concrete. PVC is best, but EMT isn't forbidden.


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## eddy current (Feb 28, 2009)

CoolWill said:


> I am just pointing out the fact that EMT is still allowed in concrete. PVC is best, but EMT isn't forbidden.


We use a lot of ENT (core line) up here in slabs. Plastic corrugated tubing. It Just pushes into boxes and fittings.


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## B-Nabs (Jun 4, 2014)

eddy current said:


> Also, so much faster to install Plastic and just strap it with tie wire. The boxes and fittings are also much faster to install and last longer.
> 
> 
> 
> Have not seen EMT getting installed in a slab for many years


We have one jurisdiction around here that requires EMT stubs out of the slab, no PVC elbows or "cups". You have to transition from ENT to an EMT elbow within the concrete. It's real dumb. 

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## cabletie (Feb 12, 2011)

Most specs are for rigid when penetrating slabs. Most jobs here prohibit conduit in slabs. Probably because most our slabs are only 5-1/2” thick on Q-Deck. 

https://www.graybar.com/store/en/gb/yard-conduit-elbow-1-in-89029032#{Size:1%20in.}


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## eddy current (Feb 28, 2009)

CoolWill said:


> I am just pointing out the fact that EMT is still allowed in concrete. PVC is best, but EMT isn't forbidden.


It should be IMO. Too many times I have seen where it has completely rotted away


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## CoolWill (Jan 5, 2019)

eddy current said:


> It should be IMO. Too many times I have seen where it has completely rotted away



Unless the EMT is used for bonding the circuit, the worst that would happen is it rots away and leaves a circular concrete tube instead.:vs_laugh:


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## eddy current (Feb 28, 2009)

CoolWill said:


> Unless the EMT is used for bonding the circuit, the worst that would happen is it rots away and leaves a circular concrete tube instead.:vs_laugh:


I was called to check an underground parking garage exhaust fan where The maintenance guy replaced the motor. It worked but he said he was feeling tingles if you touch it. It was originally a 3 phase motor run in slab EMT with no bond wire. He replaced it with a single phase motor by mistake and used a hot wire as a bond. The old blue wire looked green in the bad lighting. Because the EMT feed was rotted away there was no bond. the fan motor housing and the fan frame were live! :vs_laugh:


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## CoolWill (Jan 5, 2019)

eddy current said:


> I was called to check an underground parking garage exhaust fan where The maintenance guy replaced the motor. It worked but he said he was feeling tingles if you touch it. It was originally a 3 phase motor run in slab EMT with no bond wire. He replaced it with a single phase motor by mistake and used a hot wire as a bond. The old blue wire looked green in the bad lighting. Because the EMT feed was rotted away there was no bond. the fan motor housing and the fan frame were live! :vs_laugh:



Maintenance guys... more dangerous than the live motor frame


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## MTW (Aug 28, 2013)

CoolWill said:


> Unless the EMT is used for bonding the circuit, the worst that would happen is it rots away and leaves a circular concrete tube instead.:vs_laugh:


If only that were the case. I do work in a 1963 building with EMT in the slab. So far I've had to re-pipe one panel feeder overhead and disconnect and abandon a branch run for outlets. It's not going to get any better at this point. :no: Had the exact same scenario happen in another building I worked in of the same vintage. Several feeders and branch circuits shorted out and had to go overhead.


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## eddy current (Feb 28, 2009)

Is there a rule in the NEC that says an EMT in a slab must have a bond wire?

There is one in the CEC.


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## B-Nabs (Jun 4, 2014)

eddy current said:


> Is there a rule in the NEC that says an EMT in a slab must have a bond wire?
> 
> There is one in the CEC.


Isn't that only slab in contact with the earth? I don't have a code book handy. 

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## eddy current (Feb 28, 2009)

B-Nabs said:


> Isn't that only slab in contact with the earth? I don't have a code book handy.
> 
> Sent from my SM-G920W8 using Tapatalk


Isn’t all slab in contact with earth?


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## MikeFL (Apr 16, 2016)

In regards to how to run your conduit through a beam, you don't, unless the engineer whose beam that is says it's ok.


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## wcord (Jan 23, 2011)

eddy current said:


> Isn’t all slab in contact with earth?


technically speaking, a structural slab on voidform would not be classified as slab-on-grade.
12-930(1)(b)


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## telsa (May 22, 2015)

CoolWill said:


> EMT is allowed in concrete.


Absolutely NOT in the Bay Area.

You'll go down in flames attempting it. :sad:

But why even try?


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## telsa (May 22, 2015)

eddy current said:


> I was called to check an underground parking garage exhaust fan where The maintenance guy replaced the motor. It worked but he said he was feeling tingles if you touch it. It was originally a 3 phase motor run in slab EMT with no bond wire. He replaced it with a single phase motor by mistake and used a hot wire as a bond. The old blue wire looked green in the bad lighting. Because the EMT feed was rotted away there was no bond. the fan motor housing and the fan frame were live! :vs_laugh:


The dude was COLOR BLIND.

I've seen it over and over -- and they have not.

Flashlights, anyone?


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## CoolWill (Jan 5, 2019)

telsa said:


> Absolutely NOT in the Bay Area.


I'm talking about the NEC. Local codes may vary.



> You'll go down in flames attempting it. :sad:


There's plenty of flames in the Bay area.



> But why even try?


I would not. Not in the Bay area, nor anywhere else. The point was that it's allowed. French fry's comment made it seem as if it were forbidden.


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## macmikeman (Jan 23, 2007)

We used to have a guy (inspector) who always insisted we never break a slab with plastic conduit. He always wanted to transition a lateral run to rigid just before turning it up. I always demanded he show me in the code book where it says that. He claimed it was in the Honolulu Code book. I looked in that too and he was full of it. Gone now. Like Shunk said, it's like pulling your hand out of a bucket of water. Ten minutes later and the ripples are all gone.


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## eddy current (Feb 28, 2009)

wcord said:


> eddy current said:
> 
> 
> > Isn’t all slab in contact with earth?
> ...


Yeah I guess so.

I’m just so against EMT in a slab and EMT without a bond wire that I’ve always convinced myself they are code violations even though they are not. 

Lol


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## joebanana (Dec 21, 2010)

CoolWill said:


> Unless the EMT is used for bonding the circuit, the worst that would happen is it rots away and leaves a circular concrete tube instead.:vs_laugh:


EMT rots out where it leaves the slab, right flush with it. That's what the 20 mil. tape is for, but not everybody uses it. It always seems to rust out where you can't get a coupling on it, without chipping out concrete.


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## B-Nabs (Jun 4, 2014)

eddy current said:


> Isn’t all slab in contact with earth?


Only slab on grade is in contact with the earth. Any concrete building has many slabs not in contact with the earth, on all but the lowest floor.

All that being said, I would never put EMT in a slab if I had a say in the matter. 

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## Southeast Power (Jan 18, 2009)

When I started in the trade we ran PVC on the first floor and then transitioned to EMT the rest of the way up.
I haven't done much slab work in the last 30 years by personal choice but, I believe everyone should have a months long taste of it. 
I understand not that jobs are all smurf in the slab.
I dont know that for sure and dont want to find out. :smile:


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## splatz (May 23, 2015)

macmikeman said:


> We used to have a guy (inspector) ... Gone now. Like Shunk said, it's like pulling your hand out of a bucket of water. Ten minutes later and the ripples are all gone.





Saxon White Kessinger said:


> *Indispensable Man
> *
> Sometime when you’re feeling important;
> Sometime when your ego’s in bloom
> ...


Indispensable Man, by Saxon White Kessinger


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