EMT Overhead vs RGS In Slab

[Alwayslearningelec]

Which would you say is quicker/cheaper to install all else being equal. Obviously RGS alway more labor intensive and more expensive then EMT but in this case it due to not needing racks/supports it may be cheaper and quicker.

 

[Dennis Alwon]

Which would you say is quicker/cheaper to install all else being equal. Obviously RGS alway more labor intensive and more expensive then EMT but in this case it due to not needing racks/supports it may be cheaper and quicker.

Not knowing what you will have to face overhead then I would guess it would be better underground.

Emt can be used in concrete in many cases but I would get feedback from others whether that is a bad idea.

358.10 Uses Permitted.

(A) Exposed and Concealed.

The use of EMT shall be permitted for both exposed and concealed work for the following:

• (1)
  In concrete, in direct contact with the earth, in direct burial applications with fittings identified for direct burial, or in areas subject to severe corrosive influences where installed in accordance with 358.10(B)
• (2)
  In dry, damp, and wet locations
• (3)
  In any hazardous (classified) location as permitted by other articles in this Code
• (4)
  For manufactured wiring systems as permitted in 604.100(A)(2)

 

[NoahsArc]

RGS=RMC apparently
Really depends on a lot of factors.
Do you have other things to install (will need the racks anyway) or is it a one-off?
How kinky is the run if you do it in the air? How cluttered is the ceiling/wall, how high to the pan/joists? What wire size are you running?
You can run stainless steel EMT in concrete per 358.10A. I've seen that done before on decks. Is this a deck or a ground slab (IMC/RMC only in earth typ, a lot more corrosion to deal with)?

In my experience, we typically run through the slab for subpanel feeds, where the savings on wire (probably Al as well) are significant due to a direct line, and little else.

 

[infinity]

Running conduit in the deck can be a money saver depending on a few factors. You'll need a good layout man and a good deck crew. If your crew is lousy and half of your stub ups end up outside the wall you won't be saving any money by running in the deck. We would typically use PVC in the deck with RMC elbows for the stub ups. EMT can be used in the deck but it often gets destroyed by the other trades. I would not recommend EMT elbow stubs ups (we learned that the hard way). If you must use them then run over head.