I started the re-using an existing EMT circuit project that I posted here last week and I have encountered a problem – establishing a straight pathway for the 3/4″ (or 1/2″) conduit. I thought I would attach it to the bottom of the floor joist. The floor joist are already crowed with several other EMT runs, a black iron gas line and a copper water lines. At some time, I need to cross the non-EMT lines to run my own EMT.
What’s the skinny on flexible, metal conduit?
Replies
It is a perfectly fine wiring method but I would pull a ground wire through it and be sure you strap it like you would with Romex (within 12" of the box and every 4.5 feet). Be sure you get the right connectors for the boxes. There is one school of thought that says these are "box" connectors so you need a J box at the transitions between EMT and FMC. Other say a conduit body is fine.
Perfectly Fine Wiring Method
Thanks for the comment.
This run is short, probalby less than 20 feet, starting as 3/4" EMT from the breaker panel. I would put a box on each end of the FMC or maybe a combination (transition) coupling on one end and a box on the other end so that I could reduce to 1/2" EMT.
I'm thinking about a 25' piece of 3/4" of Southwire Reduced Wall, Flexible Aluminum Conduit.
pull a piece of string through that FMC before you install it. It is a bitch trying to push wire through FMC if it is more than a few feet
Bending EMT
Thanks for the comments!
If it were 1/2" EMT, I might try it as I have that tool. I do not have a bender for 3/4" and the 25' of FMC is the less expensive option.
FMC
How about Southwire Liqua Flex 1/2-Inch-by-25-Foot Flexible Liquidtight Metallic Conduit?
richardi
Liguid-tight is unnecessary and 2x+ the cost of alum FMC. Unless it is going through a wet location. Fittings are also quite expensive.
Instead of adding j-boxes at each end of the FMC use condulet bodies, or what is commonly called pulling C's. Box connectors will thread into each end and you won't need to fasten a box to the joist. Use j-boxes if you are going to branch off of the circuite.
I posted this same thing a few days ago, but it never showed up. Guess it got lost in cyber space.
http://www.womackelectric.com/products/Catalogs/PDF/Crouse%20Hinds%20Catalog.pdf
Keep the fmc pulled tight from transition to transition and you can pull through it fairly easily. Solid wire can sometimes be pushed through shorter runs of fmc with no problem, but stranded generall needs to be pulled via fish tape, fish sticks or pull wire/string.