How to apply 120 psi torque

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  #1  
Old 11-28-05, 05:45 PM
fused
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Question How to apply 120 psi torque

Hi, there. I was wiring my new panel with the help of a nifty little torque driver. Very useful tool for those of us who cannot easily tell 15 psi (for 14 awg wire) from 20 psi (for 12 awg). Then I got to the main lugs. The wire for these should be 2 awg and the torque 120 awg. These have inset hex heads. My torque driver is out of its league; it goes to 50 psi. Is there a special long-handle hex wrench, and how can you tell when you are reaching that high torque?
 
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  #2  
Old 11-28-05, 05:59 PM
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Gee. I just tighten the crap out of stuff with a screw driver, nut driver, or whatever. Torque wrenches? Really? I have never seen electricians I have been around, "torque" down wires, to specs, with anything resembling torquing down the headbolts on a car. Hmmm. Maybe I'm about to learn something here.

Tip: Long screw drivers apply more torque with less applied pressure due to the torsion twist of the screw driver. I own super long screw drivers for this purpose. This is not theoretical poppy ****, either. I have actually been able to see the screw driver blade twist, then snap loose rusted on screws, already! I just bought a new one at Menards for under $4. They have hardened steel heads on them.

I had to follow up behind a "blind" (I think he left his bifocals at home that day) licensed electrician once, when I found half of his screws to the breakers were loose when one circuit lost connection. I found most others loose as well. Maybe HE should have used a torque wrench.
 

Last edited by ecman1; 11-29-05 at 03:47 PM.
  #3  
Old 11-28-05, 06:00 PM
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Most auto supply or sears have torque wrenches in inlb. I don't know if they go up to 120 inlb though. With an extention it should work. Electronc stores sell torque drivers in inlb but the cost an arm and a leg. If you have a small ftlb torque wrench 120 inlb = 10 ftlb HTH
Ollie
 
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Old 11-28-05, 06:20 PM
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Fused, I do small wires by feel. I don't crush the crap out of them so as to kill the wire, yet not too loose either. Like Ollie said, I'm too cheap to buy the $$$ torque drivers for the small stuff.

On the other hand....
ecman, you do not torque your panel and meter connections? For shame. You don't have an in/lb 3/8" torque wrench on your truck? I thought this was a standard electrcian's tool.

I got Craftsman for under $100.
 
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Old 11-28-05, 06:22 PM
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OH, BTW fused, it's in/lb (inch pounds), not PSI. PSI is pressure, not torque.
 
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Old 11-28-05, 06:30 PM
fused
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Lightbulb Sears, right

Thanks, you all. I wasn't thinking "automotive"; I was thinking "electrical." (I am not a DYI car mechanic.) Of course, Sears has all kinds of torque wrenches, going up to more than enough ft/lb, not psi.
 
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Old 11-28-05, 07:41 PM
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Originally Posted by Speedy Petey
OH, BTW fused, it's in/lb (inch pounds), not PSI. PSI is pressure, not torque.
At the risk of hairsplitting, the units for torque are in-lb (inches times pounds), not in/lb (inches per pound). One in-lb is the amount of torque produced when one pound of force is applied to a one inch long torque arm (or a half pound of force applied to a two inch torque arm, etc.)...
 
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Old 11-28-05, 09:30 PM
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Sorry, punctuation mistake.
I am a long time motorhead so I knew the basic torque theory.
 
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Old 11-29-05, 03:59 PM
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Originally Posted by Speedy Petey
Fused, I do small wires by feel. I don't crush the crap out of them so as to kill the wire, yet not too loose either. Like Ollie said, I'm too cheap to buy the $$$ torque drivers for the small stuff.

On the other hand....
ecman, you do not torque your panel and meter connections? For shame. You don't have an in/lb 3/8" torque wrench on your truck? I thought this was a standard electrcian's tool.

I got Craftsman for under $100.
I am not an electrician. Just a lowly maintenance man with like an almost 35 year work history in woodworking, construction (big + housing), cointracting for building/remodeling and maintenance. A lot of what I do is not really allowed, but inspectors know of me and my abilities and as long as I don't go advertising or hiring out my services (other than working for the landlords that I do), they don't say anything. They 'know' that all us maintenance guys do all this stuff to save the landlord money. Plus I am one myself.

I don't get heavily involved with actually doing panel box work. Although I have snuck in a sub panel here and there a few times. Often times building permits are taken out when that type work is done and the licensed guy that does work for the guys I work for comes out and does that big stuff, like new weatherheads, panels, subpanels, etc. All I do is tighrten the wires on the circuit breaker and go from there.

The last time I dealt with a torque wrench was 20 years ago when I rented one to torque down the head I had rebuilt for my dad's Mazda.
 
  #10  
Old 11-29-05, 04:10 PM
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Speedy Petey...Sorry, punctuation mistake.
I am a long time motorhead so I knew the basic torque theory
I think everyone knew what you meant.

I always thought in-lb was....one grunt.

I always thought in/lb was....two grunts.
 
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Old 11-29-05, 04:52 PM
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Oh. Ok, sorry ecman1. I assumed your handle stood for "Electrical Contractor Man".
My mistake.
 
  #12  
Old 12-02-05, 08:09 AM
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Anyone can tighten down hard enough to make sure the wire doesn't come loose. torgue setting is to maintain the proper conductivity to avoid heat build up at the connections. Always made sense to me but I haven't bothered to buy the wrench yet and I have only ever met ONE electrician that owns an in-lb screwdriver. And I've met alot of them on job sites over the years. Even the guy that does own one doesn't use it. It's just there in case the inspector asks about it.
So I ask you - what's the point of spending all the time and money to develop a spec if no one bothers to use it? I bet there are alot of failures out there because somone didn't use it but I doubt many of them were catastrophic failures with injuries.
 
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