How long to run and pull a feeder?

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Smart $

Smart $

Esteemed Member
Location
Ohio
LarryFine said:
Cool idea! Are the bolts 3/8" or are they only 1/4"? I'll have to check some tomorrow.

Jamming two nuts together gives you an easy way to grip and turn the rod, by the way.
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A few thoughts:

IIRC, most minnies cannot accomodate a 3/8 rod without drilling out the hole. Though listed securing/support is not required, drilling out the hole will invalidate the hanger's load rating.

Using the rod in lieu of the furnished securing bolt and jam nut will invalidate the clamps load rating.

If you have to get up to the bar joists to attach your hanger system, you may as well dispense with the hanger system and run the conduit up there. You will save time for certain, and material will be a cost tradeoff between hanging system and guessing per OP 10-15' longer run (i.e. extra conduit, fittings, securing means, and wire).
 
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iwire

iwire

Moderator
Staff member
Location
Massachusetts
Smart $ said:
Using the rod in lieu of the furnished securing bolt and jam nut will invalidate the clamps load rating.
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Thanks for reiterating what was clearly stated.:grin:

Might as well mention we should not support from the bottom chord of the truss and that some areas require a safety strap on all beam clamps.
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Smart $ said:
Hmmm... must of missed it :mad:
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I understand, that happens to me as well.

iwire said:
Take the bolt out of it and install a 6' threaded rod in it's place. Now get on your ladder hold the threaded rod by the end and hook the beam clamp on the truss. Get channel locks or vice grips and tighten the rod up to hold the clamp in place. Now obviously this does reduce the clamps overall capacity but you are not using them nearly to capacity this way and you will never have to get up as high as the truss.
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Smart $

Smart $

Esteemed Member
Location
Ohio
iwire said:
...

Might as well mention we should not support from the bottom chord of the truss...
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This is a requirement I find hard to swallow. When considering adding dead loads, whether supported from the bottom chord or top chord still adds the same amount of dead load to the truss. I can understand the bottom chord having a lower ratiing if it is of inferior construction (such as smaller size angles, for example). Yet if they of identical construction, I don't see the difference.
 
Mr. Wizard

Mr. Wizard

Senior Member
Location
Texas
I would have to agree with i-wire on this one. MC cable would be the most efficient route to go. If you have to go all of the way to the beams to attach your supports, then you will be up high enough to feed the MC. Begin by getting a pull rope up in the beams from one side of the building to the other, attach MC and let 'er rip, chip. Make sure you position the MC so it pulls with the jacket and not against it. Also make sure if have to transition to rmc or emt when you come down through the ceiling to the trough, I've done plenty of jobs where the owner wanted to see conduit instead of MC coming through the ceiling. Good luck!
 
Mr. Wizard

Mr. Wizard

Senior Member
Location
Texas
Also with MC, as long as it's inside of the chord of the joists, you can do away with the hangers and allthread. Just make sure you get some caddy clips to strap the MC to the joists. One man lift to get up to the red iron?
 
LarryFine

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Smart $ said:
Using the rod in lieu of the furnished securing bolt and jam nut will invalidate the clamps load rating.
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The only hardware I've ever seen supplied with Minnies is the clamping nut and bolt, not mounting hardware.

Added: Oh, the beam clamp.

If you have to get up to the bar joists to attach your hanger system, you may as well dispense with the hanger system and run the conduit up there.
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I'll look into it. Thanx!
 
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iwire

iwire

Moderator
Staff member
Location
Massachusetts
Smart $ said:
This is a requirement I find hard to swallow. When considering adding dead loads, whether supported from the bottom chord or top chord still adds the same amount of dead load to the truss. I can understand the bottom chord having a lower ratiing if it is of inferior construction (such as smaller size angles, for example). Yet if they of identical construction, I don't see the difference.
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I agree 100%, yet I am stuck with that requiment many times.:roll:
 
W

wawireguy

Senior Member
Aluminum MC : ) Unless you have to use copper. I pulled some AL 250mcm MC on the red iron in a t-bar ceiling one time. Wasn't to bad at all. It did kick a lot of dust on some govt worker types desk that made them unhappy. The pull was pretty easy though. It was about the same distance you're going and not a straight line at all.
 
P

Power Tech

Senior Member
Location
Lebec, California
If you have some splitbolts you want to use up I used to take 1 wire for 2 panels. Loop them and bolt in the center. 1 splitbolt, 2 panels.

I now use the Polaris clamps.

I'm sure you knew this.;)
 
B

benaround

Senior Member
Location
Arizona
Smart $ said:
This is a requirement I find hard to swallow. When considering adding dead loads, whether supported from the bottom chord or top chord still adds the same amount of dead load to the truss.QUOTE]

It was explained to me like this. The top chord is in compression and the bottom chord is

in tension. Push down on the top chord and the bottom chord will push back up, pull down

on the bottom chord and the top chord will not pull back up it will fail.
Click to expand...
 
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