Sizing Vertical Wall Mounted Strut Channel Supports

[Tainted]

Suppose I have like (10) 2" conduits going up 200ft against the wall and I need to support them using strut channel. How would I go about sizing the channel supports? they come in many different shapes and sizes and I'm not sure how it's typically sized in the field even though I see them all the time. See example below.

 

[tom baker]

They are all 1 5/8 wide, 12 gage is the heaviest, so it comes down to depth.
I would use a shallow strut, just guessing
but fastening every 2 feet, you’ll want solid anchors. The largest anchor that can go inside strut is 3/8 for the socket to fit.

 

[LarryFine]

I usually use square strut. There can be interference between the straps and the mounting bolts with the shallow stuff.

 

[infinity]

We only use the Kindorf brand and the three standard sizes that we use are "¾", "1½" and occasionally "3" inch. The ¾" is typically 14 gauge and the others 12 gauge. For your 10-2" conduits we would use 1½" spaced about every 6' as mentioned because of the straps hitting the support hardware on the 3/4". IMO what's more important than the strut type is the type of anchors used to attach to the wall. What kind of wall is it?

 

[Tainted]

We only use the Kindorf brand and the three standard sizes that we use are "¾", "1½" and occasionally "3" inch. The ¾" is typically 14 gauge and the others 12 gauge. For your 10-2" conduits we would use 1½" spaced about every 6' as mentioned because of the straps hitting the support hardware on the 3/4". IMO what's more important than the strut type is the type of anchors used to attach to the wall. What kind of wall is it?

what if you want to stack conduits 2 rows of 5? can you stack as many struts as you want?

 

[LarryFine]

what if you want to stack conduits 2 rows of 5? can you stack as many struts as you want?

I can.


Yes, if your support hardware is well attached.

 

[rambojoe]

You can also 4sq extension to 20,000' too...

 

[infinity]

what if you want to stack conduits 2 rows of 5? can you stack as many struts as you want?

Two rows is fine, we just build it out with threaded rod. There is a limit as to how many rows because at some point the outer rows may require some type of angle support to keep them from sagging.

 

[Tainted]

We only use the Kindorf brand and the three standard sizes that we use are "¾", "1½" and occasionally "3" inch. The ¾" is typically 14 gauge and the others 12 gauge. For your 10-2" conduits we would use 1½" spaced about every 6' as mentioned because of the straps hitting the support hardware on the 3/4". IMO what's more important than the strut type is the type of anchors used to attach to the wall. What kind of wall is it?

Not sure what wall yet, but how do you determine what depth and gauge the strut should be?

 

[infinity]

Not sure what wall yet, but how do you determine what depth and gauge the strut should be?

For 3/4" the lighter 14 gauge will work but we just use 12 gauge for everything else. The depth is usually determined by the size of the raceway. If you're strapping the strut to the wall then 3/4" will work for 2" conduit. 1½" is just easier to work with when installing the straps so that is what I would use.

 

[Buck Parrish]

If you get to three, please send pics, this is going to be a good one. I know it can be done.

Don't forget the AHJ might have a little say in this.

 

[Tainted]

For 3/4" the lighter 14 gauge will work but we just use 12 gauge for everything else. The depth is usually determined by the size of the raceway. If you're strapping the strut to the wall then 3/4" will work for 2" conduit. 1½" is just easier to work with when installing the straps so that is what I would use.

Ok, suppose I stack 2" conduits 2 rows of 5 against the wall, using the 1-1/2 you mentioned how much total depth would be taken up? Would I just have to add the depth 2 struts and 2 conduits? Would I have to add the depth of the strap?

 

[Eddie702]

@Tainted

I am assuming you mean strut run horizontally on a wall with conduit run vertical, then another strut directly in front of that one secured with threaded rod to the strut on the wall. Yes, you would have to add for that portion of the strap that is proud of the front face of the conduit x2. Probably 2" total depending on pipe size

imho sizing come in when you use the strut to span between supports mounted overhead

 

[Tainted]

@Tainted

I am assuming you mean strut run horizontally on a wall with conduit run vertical, then another strut directly in front of that one secured with threaded rod to the strut on the wall. Yes, you would have to add for that portion of the strap that is proud of the front face of the conduit x2. Probably 2" total depending on pipe size

imho sizing come in when you use the strut to span between supports mounted overhead

Yes, also I could probably reduce the depth by installing the 2nd strut and strap above the 1st strut and strap right? The tip of the strap takes up like 1" of space

 

[Eddie702]

Yes, also I could probably reduce the depth by installing the 2nd strut and strap above the 1st strut and strap right? The tip of the strap takes up like 1" of space

Yes

 

[Carultch]

@Tainted

I am assuming you mean strut run horizontally on a wall with conduit run vertical, then another strut directly in front of that one secured with threaded rod to the strut on the wall. Yes, you would have to add for that portion of the strap that is proud of the front face of the conduit x2. Probably 2" total depending on pipe size

imho sizing come in when you use the strut to span between supports mounted overhead

I would recommend something much more substantial than a threaded rod for supporting the outer layer of strut. Threaded rod is a decent solution when gravity works in your favor and the load in the rod is primarily tension. An example being, a conduit run hung from the ceiling on strut trapeze setups. However, in this case, that threaded rod would be primarily loaded in bending, which isn't what most threaded fasteners are designed to support. Threaded fasteners are meant for tensile and shear loads, but not bending loads. You can use them for bending loads if the fastener is strong enough to withstand the total load applied, but in general, I wouldn't recommend counting on threaded rods to do this.

My solution would be to use angle brackets and a perpendicular-to-the-wall strut on both sides, to support the outer strut and outer layer of conduits. If necessary due to the load of the conduits, I'd also recommend adding a diagonal brace on each side, to reduce and distribute the bending load. Think of the bracing that would support it a cantilevered shelf on the wall.

Yes, also I could probably reduce the depth by installing the 2nd strut and strap above the 1st strut and strap right?

In most cases, you cannot use a raceway as a structural support, if it is also being used as a raceway. You can use conduit material for building structural supports, but only if it is not also being used as a wiring method. There are some exceptions where conduit can be used as a structural support while simultaneously being a wiring method, but this isn't one of them.

You can strategically stagger your struts as you see fit, to do what you are describing.

 

[infinity]

Ok, suppose I stack 2" conduits 2 rows of 5 against the wall, using the 1-1/2 you mentioned how much total depth would be taken up? Would I just have to add the depth 2 struts and 2 conduits? Would I have to add the depth of the strap?

Yes you would have the depth of the strut+OD of the raceway+strap. For 1.5" strut and 2" EMT you're looking at about 1.5+1.5+2.25+2.25+3/4+3/4=9" from the wall to the top of the strap. If you use 3/4" strut instead of 1.5" you end up with about 7.5".