Supporting Conduit

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metelsaatlsd

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In the NEC I have seen that EMT should be supported min 3ft from an opening and at least every 7ft after. Does that apply for both commercial and residential jobs? Also, does the footage requirement change if the conduit is being run on a unistrut rack? Thanks.
 
metelsaatlsd said:
In the NEC I have seen that EMT should be supported min 3ft from an opening and at least every 7ft after. Does that apply for both commercial and residential jobs? Also, does the footage requirement change if the conduit is being run on a unistrut rack? Thanks.
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You will find your answers in 358.30

Roger
 
Every ten feet along the run - at least one per piece - so that there is no point more than ten... As well as no more than three feet from every box. All conduit - everywhere - strut or not. Those are minimums - you can always install more with and/or due to some common sense.

IMO supports at a box look and feel better secured at ~14"-30" from the box, and likewise couplings.... (Note those dimensions would put you at 16" increments from a 4" box center...) :wink:

Not sure where you got seven from - a picture as an example in the handbook???? :wink: If so - look again...
 
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e57 said:
... at least one per piece ...
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Where does the Code say one support per piece?

E.g. can't I treat two five-foot scraps with a coupling
just like a 10-foot piece, i.e. one clamp?
 
rexowner said:
Where does the Code say one support per piece?

E.g. can't I treat two five-foot scraps with a coupling
just like a 10-foot piece, i.e. one clamp?
Click to expand...

It doesn't - I meant to imply the one at the box - the one at the box is only necessary - if at a box... But good catch.... Good question!

But truthfully, many inspectors would nail you for not supporting each peice - at least once. And would then call it unsupported...
 
e57 said:
But truthfully, many inspectors would nail you for not supporting each peice - at least once. And would then call it unsupported...
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That's pretty ridiculous and not supported by the NEC.
 
I'm a bit confused? If the conduit is 10ft long how would you get away from not having a support in at least every piece?
 
russ said:
I'm a bit confused? If the conduit is 10ft long how would you get away from not having a support in at least every piece?
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Russ, you may have short sections coupled together to make up 10 feet of the run, these short sections do not need individual supports.

Roger
 
russ said:
I'm a bit confused? If the conduit is 10ft long how would you get away from not having a support in at least every piece?
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You have to cut the conduit, and you end up with scraps.
Every run is not 10,20,30,40... feet long. E.g. if you end up
with a 54 foot run, you end up with at least a 6 foot scrap.
And, as much as I would like to be the uber-conduit-bender
sometimes, it's just easier to make nearby bends in
different directions out of two different pieces. In
any case, it's not that uncommon in the middle of a run
for the easiest thing to do is use less than a full length
piece - often available in the scrap pile. There is no
need to support every short piece as long as there
is support every 10 feet.
 
Many times for whatever reason, you cannot place supports 10 feet apart. We will typically put our first support at 36" and than every 60" from there. That way, you have asthetics as well as the ability to move the bracket a couple inches here or there if there happens to be an obstruction.
 
[Q]Every ten feet along the run - at least one per piece - so that there is no point more than ten... As well as no more than three feet from every box. All conduit - everywhere - strut or not. Those are minimums - you can always install more with and/or due to some common sense.[/Q]

Ok I was commenting with this statement in mind.

I missed the comment in the following post mentioning the coupling of pieces.
 
sybrandy said:
Many times for whatever reason, you cannot place supports 10 feet apart. We will typically put our first support at 36" and than every 60" from there. That way, you have asthetics as well as the ability to move the bracket a couple inches here or there if there happens to be an obstruction.
Click to expand...

I may not have worded my response with total precision.
By "every 10 feet", I meant to imply "10 feet or less". I don't think I could be precise at 10' without taking
all day.

10 feet or 9' or 8' seems fine to me depending on what
kind of support is available. Every 10' is easy
to eyeball based on the sticks, and just go less
distance based on the available support. I usually
go from one end to the other, so I might end up with one
extra support. FWIW, I usually put my first support at about 24-30" if I have a choice, because I don't usually
measure.

I don't see a reason to go to 5' (60"), unless the
only available support is 5' apart. I don't mean
to be nitpicky, but it seems curious to go to the
max (36") at one point, and 50%
of the max everywhere else.

Anyway, everybody does conduit slightly differently, so
if we all meet code, it's all good.:smile:
 
okay, I guess I should have worded it a little different too. I start at UP TO 36" for my first support. A lot of times, I have to go that far to allow for my conduits' offset to reach where I can secure it. Yeah, maybe a little picky for the 60", but it usually ensures an even support design (it looks good) :)

I tend to use a lot of larger conduit, and mainly rigid
 
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