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#199586 - 03/02/11 07:58 AM The Weight  
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,308
A concern i haven't had to really consider down to specifics before is the weight of a conduit run with wire installed

Best i can do is ring up what i'd call hang weight>

http://www.interfacebus.com/Aluminum_Wire_AWG_Size.html

for example, via this chart, 4/0AL X 4 = 780lb's per 1000 feet

All fine and well, but what about the pull weight during the install? i'm not sure how to calculate that, if there's any calc at all?

I would think any conduit install, be it individual clips, beeline, kindorf , or whatever , would need to be sized and installed toward a pull weight vs. the XXX required NEC attachments per ft.

Further, the roofing system it's all hung to has to be able to handle it too. Most industrial roofing here is required to have an XXX per foot snow load capacity

am i off in the worry wart stratosphere here?

~S~


Work Gear for Electricians and the Trades

#199590 - 03/02/11 10:06 AM Re: The Weight [Re: sparky]  
wire_twister  Offline
Member
Joined: Jul 2007
Posts: 265
Georgia USA
Sparky,
just the way I see it, but if you pull the wire in with a tugger, it is usualy attached to and pulling on the conduit in a straight line, so no down pull except the weight of the tugger. On pulls where the wire is too small to need a tugger, I do not think weight is an issue. Here is a link to a site I use with some good info on wire and conduit weight. www.mc2-ice.com, when the page loads go to the support pulldown and select estimators reference.


#199592 - 03/02/11 11:23 AM Re: The Weight [Re: sparky]  
ghost307  Offline
Member
Joined: May 2005
Posts: 902
Chicago Illinois USA
Generally I see wire pulls that are in line with the conduit run, even if it means rigging a snatch block for the rope.


#199594 - 03/02/11 12:24 PM Re: The Weight [Re: sparky]  
HotLine1  Offline


Member
Joined: Apr 2002
Posts: 6,830
Brick, NJ USA
~s~:
Where you are heading is into the realm of PEs.

I agree on the pull utilizing the pipe theory for straight pulls, but I hear where you are going on the 'down' type pulls.

Honestly, over many years...I never thought about it, and can say it never was an issue.

As to the structure being capable of handling the added weight...leave that to the Architect, or structural engineer types. And...good old common sense!


#199614 - 03/02/11 09:13 PM Re: The Weight [Re: wire_twister]  
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,308
Originally Posted by wire_twister
Sparky,
just the way I see it, but if you pull the wire in with a tugger, it is usualy attached to and pulling on the conduit in a straight line, so no down pull except the weight of the tugger. On pulls where the wire is too small to need a tugger, I do not think weight is an issue. Here is a link to a site I use with some good info on wire and conduit weight. www.mc2-ice.com, when the page loads go to the support pulldown and select estimators reference.


neato twister, okay.... by this handy chart i have>

74---#500 @ 1.662 lb's per ft = 122.98 total lb's per ft

32---#350 @ 1.182 lb's per ft = 37.824 lb's per ft

6--3/0 @ .578 lb's per ft = 3.468 lb's per ft

2--1/0 @ .375 lb's per ft = .75 lb's per ft

8---#3 @ .191 lb's per ft = 1.528 lb's per ft

31----4" emt runs @ .39 lb's per ft = 12.09 lb's per ft

Approx total = 178.64 lb's per ft

~S~


#199615 - 03/02/11 09:25 PM Re: The Weight [Re: HotLine1]  
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,308
Originally Posted by HotLine1
~s~:
Where you are heading is into the realm of PEs.


and asprin, bengay, mortin.....

Quote

As to the structure being capable of handling the added weight...leave that to the Architect, or structural engineer types. And...good old common sense!


very true, being i'm not a structual anythingHotOne, i just thought a quick calc would get them interested enough to investigate

my impression is, nobody's considered it at all.....

~S~


#199622 - 03/02/11 10:27 PM Re: The Weight [Re: sparky]  
HotLine1  Offline


Member
Joined: Apr 2002
Posts: 6,830
Brick, NJ USA
~s~:
You say..."my impression is, nobody's considered it at all.."

Routinely, either the Building Subcode or I request structural support documentation, via an architect, or engineer for electrical equipment that is proposed or installed supported from structural framing.

No, it's not requested for a single run of pipe, it's basically job dependent. Hanging a 45KVA xfr, yes. Hanging a 112.5 KVA, oh yes! Multiple runs like 2" to 4"; bring on the drawings please!

Some of the towns I worked in as an EC required this from back in the early-mid 1990s.

You would appreciate the 12" x 18" timber (wood) beam in a old section of a strip mall that split after many years from the weight of pipes hanging from it.


#199625 - 03/02/11 10:39 PM Re: The Weight [Re: sparky]  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,083
Estero,Fl,usa
I am having brain freeze right now but I have seen a table somewhere about the weight of filled raceways.


#199638 - 03/03/11 09:54 AM Re: The Weight [Re: gfretwell]  
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,308
Originally Posted by gfretwell
I am having brain freeze right now but I have seen a table somewhere about the weight of filled raceways.


reminds me of>

[Linked Image]
BLUE BIRD OF HAPPINESS, MY A**!

It's Friggin' Freezing. There's snow up my a**, all the food's covered with
3 feet of this white sh*t, and you want ME to sing?

What?? Anne Murray's "Snowbird"? Piss Off!!

Next year, I'm flyin' to Jamaica, and smokin' dope!!

(with appologies to Anne Murray)~S~




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