# Six inch RMC



## Flyingsod (Jul 11, 2013)

Not sure how to phrase this to avoid the 13 year olds jokes, But I’m wondering if any of you have encountered 6” rigid in the wild. I’ve always known about it but I’ve never seen it anywhere let alone had to work with it. 

Mostly interested in where the hell you’d need it. Thanks


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## MotoGP1199 (Aug 11, 2014)

6" RMC is not so fun


Just started a job installing 6" RMC. It's not as fun as I would like. Tough part is getting it all to fit into a 26" circle.




www.electriciantalk.com





I only see 4". No real need to go bigger as I start to parallel stuff. Check the link above, apparently a launch pad needs 6".


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## Slay301 (Apr 23, 2018)

I’ve used it once for sleeves on a particle accelerator through like 8ft concrete walls so the could run all the cords through it with the ends made up. I also use pvc in footings as sleeves put a short piece in and then tape the ends and after they peel off the forms you can run your 4” through it


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## MikeFL (Apr 16, 2016)

Slay301 said:


> I’ve used it once for sleeves on a particle accelerator through like 8ft concrete walls so the could run all the cords through it with the ends made up.* I also use pvc in footings as sleeves* put a short piece in and then tape the ends and after they peel off the forms you can run your 4” through it


Two different inspectors should have caught that. 
Those footings are required to be continuous. Keep ya damned pipe out of the footings!
Imagine the claim if the building fails at that point and they find your sleeve. Ouch!


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## Slay301 (Apr 23, 2018)

I guess I ment to say foundation wall not the footing


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## Almost Retired (Sep 14, 2021)

i was not familiar with those two terms being different things, so i googled it
around here all they dig is the wall, the depth requirement is (2 ft ?) in undisturbed soil
there are no forms, they pour directly into the plastic lined dug ditch and fill up into the slab which is formed of course
there are also cross walls inside the perimeter wall for any planned load bearing walls in the house
i have never seen a "foot" around here


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## Dennis Alwon (May 9, 2009)

I never installed 4" rmc but I had the unfortunate job of removing 4" black iron from a ceiling in Kingston, NY's IBM plant-- not there anymore, I hear.
My back hurts thinking about that job. I can't imagine using 6" rmc


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## Slay301 (Apr 23, 2018)

Almost Retired said:


> i was not familiar with those two terms being different things, so i googled it
> around here all they dig is the wall, the depth requirement is (2 ft ?) in undisturbed soil
> there are no forms, they pour directly into the plastic lined dug ditch and fill up into the slab which is formed of course
> there are also cross walls inside the perimeter wall for any planned load bearing walls in the house
> i have never seen a "foot" around here


Ya that’s the footing or mud slab. Then the foundation gets formed on top of that


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## Almost Retired (Sep 14, 2021)

Slay301 said:


> Ya that’s the footing or mud slab. Then the foundation gets formed on top of that


so how do you differentiate between the foot and the wall if it all looks the same ? depth ?


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## glen1971 (Oct 10, 2012)

Years ago, the company I was with was bidding on some 6" GRS in the power plant. If I remember right, it is about 160# for a 10' stick. We didn't get the job, and I'm guessing it would be more ignorant than the little bit of 4" I've ran.


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## micromind (Aug 11, 2007)

2 words........unbelievable heavy. 

I've used it as stub-ups to generators at power plants, 6" PVC in the ground and rigid 90s and stub-ups. 

More than 1 guy can handle, and no one had a 6" threader so we cut our stubs and had a machine shop cut the threads.


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## Slay301 (Apr 23, 2018)

Almost Retired said:


> so how do you differentiate between the foot and the wall if it all looks the same ? depth ?


Typically the foot is a 3’x3’ hole dug with rebar cage the the wall is formed on top with concrete forms


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## canbug (Dec 31, 2015)

I've seen 6 inch a couple of times but have never used larger than 4.

We install footings below the frost line, around here 4-5' min but most of the time 8', then the wall is poured on top of that. Hence why we have basements.

Tim


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## paulengr (Oct 8, 2017)

Flyingsod said:


> Not sure how to phrase this to avoid the 13 year olds jokes, But I’m wondering if any of you have encountered 6” rigid in the wild. I’ve always known about it but I’ve never seen it anywhere let alone had to work with it.
> 
> Mostly interested in where the hell you’d need it. Thanks
> 
> ...


Really good jokes are timeless. They are still funny after 18 years.

Chemical plants and MEPs. 1250 MCM is on the charts too. Doesn’t mean it’s a good idea. It just lines the ECs pocket.


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## Slay301 (Apr 23, 2018)

paulengr said:


> Really good jokes are timeless. They are still funny after 18 years.
> 
> Chemical plants and MEPs. 1250 MCM is on the charts too. Doesn’t mean it’s a good idea. It just lines the ECs pocket.


This might be your shortest post ever


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## HertzHound (Jan 22, 2019)

I’ve never ran 6” rigid. Don’t even want to think about it. I’ve only used it for sleeves. Once we did (4) 4” RMC in duct bank for about a mile between two buildings on a base. That was back breaking enough.


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## HertzHound (Jan 22, 2019)

MikeFL said:


> Two different inspectors should have caught that.
> Those footings are required to be continuous. Keep ya damned pipe out of the footings!
> Imagine the claim if the building fails at that point and they find your sleeve. Ouch!


The big problem I see on most jobs, is that the GC waits to pick the electrical sub after site and foundation work has already started. If we can get designing before the work has started, we can save a lot of headaches later. We can get them to step the footings down if we have to, so we have room to get all the conduits through the foundation wall. This stuff never seems to get designed by the A&E. We submit shop drawings for approval by the structural engineer. The contract drawings usually have details/guidelines on window or sleeve sizes, as well as minimum distances between them and extra rebar placement.

It gets old after a while. They play games with the subs. Keep beating them down on price, while the rest of the job is moving on. Then the job gets awarded and they want a sign off on coordination in a few weeks. It will be months before we have approved gear submittals, so you just go with whatever information you have at the time, and hope it doesn’t change to much.


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