What should I use to sexure flex conduit...
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ive never seen 3/8 flex conduit...is it listed for what you are using it for?...i don't know, i'd probably just use 1/2
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2,487 Posts
Look harder. Home Depot and Lowes both have 3/8" straps. They may be in the section for bx/ac/mc fittings area.
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2,487 Posts
You are in the wrong article. Try 348.
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2,047 Posts
Thanks for the link.
Maybe I can get a list of everything I will need because lowes, menards, etc. are far away...
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6,039 Posts
348.20 Size.
(A) Minimum. FMC less than metric designator 16 (trade
size 1⁄2) shall not be used unless permitted in 348.20(A)(1)
through (A)(5) for metric designator 12 (trade size 3⁄8).
(1) For enclosing the leads of motors as permitted in
430.245(B)
(2) In lengths not in excess of 1.8 m (6 ft) for any of the
following uses:
a. For utilization equipment
b. As part of a listed assembly
c. For tap connections to luminaires (lighting fixtures)
as permitted in 410.67(C)
(3) For manufactured wiring systems as permitted in
604.6(A)
(4) In hoistways as permitted in 620.21(A)(1)
(5) As part of a listed assembly to connect wired luminaire
(fixture) sections as permitted in 410.77(C)
(B) Maximum. FMC larger than metric designator 103 (trade
size 4) shall not be used.
FPN: See 300.1(C) for the metric designators and trade
sizes. These are for identification purposes only and do not
relate to actual dimensions.
Table 344.30(B)(2) Supports for Rigid Metal Conduit
Conduit Size
Maximum Distance
Between Rigid Metal
Conduit Supports
Metric
Designator Trade Size m ft
16–21 1⁄2–3⁄4 3.0 10
27 1 3.7 12
35–41 11⁄4–11⁄2 4.3 14
53–63 2–21⁄2 4.9 16
78 and larger 3 and larger 6.1 20
Use 1/2". I failed an inspection one time because I used 3/8 to feed a water cooler.
(A) Minimum. FMC less than metric designator 16 (trade
size 1⁄2) shall not be used unless permitted in 348.20(A)(1)
through (A)(5) for metric designator 12 (trade size 3⁄8).
(1) For enclosing the leads of motors as permitted in
430.245(B)
(2) In lengths not in excess of 1.8 m (6 ft) for any of the
following uses:
a. For utilization equipment
b. As part of a listed assembly
c. For tap connections to luminaires (lighting fixtures)
as permitted in 410.67(C)
(3) For manufactured wiring systems as permitted in
604.6(A)
(4) In hoistways as permitted in 620.21(A)(1)
(5) As part of a listed assembly to connect wired luminaire
(fixture) sections as permitted in 410.77(C)
(B) Maximum. FMC larger than metric designator 103 (trade
size 4) shall not be used.
FPN: See 300.1(C) for the metric designators and trade
sizes. These are for identification purposes only and do not
relate to actual dimensions.
Table 344.30(B)(2) Supports for Rigid Metal Conduit
Conduit Size
Maximum Distance
Between Rigid Metal
Conduit Supports
Metric
Designator Trade Size m ft
16–21 1⁄2–3⁄4 3.0 10
27 1 3.7 12
35–41 11⁄4–11⁄2 4.3 14
53–63 2–21⁄2 4.9 16
78 and larger 3 and larger 6.1 20
Use 1/2". I failed an inspection one time because I used 3/8 to feed a water cooler.
Its going to feed a furnace, so I'm going to go for 1/2.
Sorry my bad.
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I am very lucky, A 20 minute drive from home puts me at Lowes, Menards, or Home Depot, and they are all close to each other.
I guess you can always order online.
Jamie
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2,047 Posts
Isn't a furnace exposed? Wouldn't it require EMT or other conduit system that is rated to provide protection from physical damage. I remember asking KC one time about using a BX whip to my furnace and he said it should not be allowed. So I replaced it with EMT.
EMT is getting really cheap, under $2 for 1/2" now.
Jamie
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1,013 Posts
Haha, I am about 10 mins on a bad day with traffic where I currently live, my new house i'll be less than 5 mins away. Where I am at, the Home Depot and Menards are directly across the street from each other.
To the op, when our furnace was replaced they used 3/4" flex and used it just as a sleave for the 14/2 romex. Total length of the run from the joist through the switch box and into the furnace is probably 4 or 5 feet.
I'll just have a j-box with flex and individual thhn inside of it.
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2,047 Posts
I just found the thread where we discussed this, this might be of use to you
http://www.diychatroom.com/f18/few-things-31363/
Jamie
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2,487 Posts
Well, "subject to physical damage" is a really fuzzy term. Romex is allowed to be exposed in places where not "subject to physical damage". If you are installing wiring in a loading dock with tractor trailers backing in, then flex would be a bad choice. But if you are whipping a circuit in for a furnace in your basement, then there really isn't a problem. Also, you might consider that EMT may transmit small vibrations from a running furnace, and might cause annoying sounds. I would not hard pipe very many pieces of equipment. Air handlers, condenser units, cooktops, ovens, transformers, pumps, lay-in fluorescent lights... etc all get flex or seal-tite whips.
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