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#63346 - 03/13/06 07:39 PM how tight do i tighten the lugs?
Clydesdale Offline
Member
Registered: 11/25/04
Posts: 138
How tight do I tighten the lugs down on a 4/0 Aluminum service conductors? Or for that matter...any lugs? I have heard it has to be 20lbs PSI...but not sure...anyone?
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#63347 - 03/13/06 07:48 PM Re: how tight do i tighten the lugs?
Active 1 Offline
Member
Registered: 02/22/03
Posts: 687
Loc: Grayslake IL, USA
Maybe you mean foot pounds, inch pounds, or nuton meters.

Torque wrench.

I don't know any defult torque numbers if you can't find manufactures specs.
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#63348 - 03/13/06 08:16 PM Re: how tight do i tighten the lugs?
Clydesdale Offline
Member
Registered: 11/25/04
Posts: 138
yeah. foot pounds.thanks. I will check out some manufacturers' websites for some info..

thanks
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#63349 - 03/13/06 11:21 PM Re: how tight do i tighten the lugs?
e57 Offline
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Registered: 05/27/03
Posts: 2876
Loc: S.F.,CA USA
Usually listed in most equipment labeling, and sometimes on the lug itself.
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#63350 - 03/14/06 05:36 AM Re: how tight do i tighten the lugs?
Last Leg Offline
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Registered: 05/04/05
Posts: 41
Loc: Houston, Texas
It is all dependent on the size and what it is made of (steel, zinc, etc). I found a chart years back that had standard tightening torques, per types and sizes, you might find something like that. Of course, manufacturers recommendations are always best.
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#63351 - 03/14/06 06:48 AM Re: how tight do i tighten the lugs?
renosteinke Offline
Cat Servant
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Registered: 01/22/05
Posts: 5316
Loc: Blue Collar Country
A little quibble...it's "pound inches'...not 'inch pounds.

Otherwise, unless the connector is marked differently, here are the values UL uses:
Slotted scrw head..50 pound inches

Hex or socket head...250 pound inches

Split bolt...500 pound inches.

This information is also published in |Ferm's Fast Finder"....which is probably the ultimate NEC index. Available from the IAEI and NFPA.
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#63352 - 03/14/06 09:00 AM Re: how tight do i tighten the lugs?
Tom Offline
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Registered: 01/01/01
Posts: 1044
Loc: Shinnston, WV USA
Everyone left out the most important torque range called "erks." This is the sound the fastener makes just before breaking or stripping out. :-)

Most meter sockets have a label that states the torque value. Sometimes for the breaker it is marked on a label in very small type or is embossed into the body of the breaker, both of which are hard for us older guys to read.
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#63353 - 03/14/06 09:43 AM Re: how tight do i tighten the lugs?
gfretwell Offline


Member
Registered: 07/20/04
Posts: 9038
Loc: Estero,Fl,usa
The "erk" brings up an interesting point. Generally torque specs are based on a lightly oiled fastener. The "erk" is actually the galling of a dry fastener in the threads. Is there a listed lubricant for these fittings?
Friction in the threads could wildly alter the actual clamping force at any given torque, particularly in a termination that has been oxidizing for a while. (In use or on the shelf)
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#63354 - 03/14/06 10:00 AM Re: how tight do i tighten the lugs?
George Offline
Member
Registered: 02/23/02
Posts: 375
Clydesdale ---

I think pressure (psi) is the best measure but since we have screw fasteners we are limited to measuring torque. Torque is a poor measure. Being affected by lubrication, finish, and dirt.
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#63355 - 03/14/06 12:01 PM Re: how tight do i tighten the lugs?
togol Offline
Member
Registered: 09/15/05
Posts: 421
Loc: NW In. USA
gfretwell,

I have used Naptha, MineralSpirits, charcoal starter...any clear solvent,
Diesel, Kerosene, just a little dab on the threads ...works like a charm

------

great for drilling and tapping too

[This message has been edited by togol (edited 03-14-2006).]
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