ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals

Topic Options
Rate This Topic
#91303 - 01/09/05 07:00 AM torque
kd Offline
Member
Registered: 12/14/04
Posts: 52
When I torque lugs using Aluminum wire, I will apply, say 50 ft. lbs., then several days later check the torque. It will be down to, say, 35 lbs, so I re-torque it. Other ECs say you should just torque it and forget it--that the loss in tightness is built-in to the required torque. Of course Copper holds its torque so it is not a problem. What do you guys and gals say about this?
Top
2017 / 2014 NEC & Related Books and Study Guides
#91304 - 01/09/05 07:47 AM Re: torque
Tom Offline
Member
Registered: 01/01/01
Posts: 1044
Loc: Shinnston, WV USA
Torque it once to the specifications for the lug & leave it alone.
_________________________
Few things are harder to put up with than the annoyance of a good example.
Top
#91305 - 01/09/05 08:37 AM Re: torque
George Little Offline
Member
Registered: 01/18/04
Posts: 1488
Loc: Michigan USA
How does an inspector know how much you've torqued a connection? I am a fan of the break away connection.
_________________________
George Little
Top
#91306 - 01/09/05 09:38 PM Re: torque
Physis Offline
Member
Registered: 12/28/04
Posts: 86
Loc: Burlingame, Ca. USA
Another reason to not like aluminum as a conductor.
_________________________
Sam, San Francisco Bay Area
Top
#91307 - 01/10/05 04:13 PM Re: torque
John Steinke Offline
Member
Registered: 04/03/01
Posts: 518
Loc: Reno,Nv., USA
Not "another" reason- THE reason! Aluminum is notorious for "creep" when over-torqued. Aluminum should not be torqued to the same values as copper for this reason.
Simply put, too much pressure causes the metal to flow, leaving you with a loose connection. Make sure the value you're using is the correct on, and not "something always used."
Top
#91308 - 01/11/05 09:31 PM Re: torque
kd Offline
Member
Registered: 12/14/04
Posts: 52
Aluminum association torque table shows the sasme values for Cooper and Aluminum.
Top
#91309 - 01/17/05 05:24 PM Re: torque
Nick Offline
Member
Registered: 08/13/01
Posts: 599
Loc: Riverside, CA
Top
#91310 - 01/18/05 08:21 AM Re: torque
resqcapt19 Offline
Member
Registered: 11/10/00
Posts: 2148
Loc: IL
The following is a very important quote from the document that Nick has posted a link to.
Quote:
It is often asked whether bolted connections require periodic retightening. The simple answer is NO. Once the connector is installed with the proper torque, repeated tightening could actually damage the connector and/or the conductor and eventually lead to a failure.

Don
_________________________
Don(resqcapt19)
Top

Member Spotlight
Member Since: 10/07/00
Posts: 3417
New in the Gallery:
SE cable question
Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box


Who's Online
0 registered (), 54 Guests and 7 Spiders online.
Key: Admin, Global Mod, Mod
 
New in the Gallery:
SE cable question
 
Top Posters (30 Days)
Admin 51
HotLine1 43
gfretwell 17
Trumpy 16
Ruben Rocha 13
 
Newest Members
clee512, Jdscott2005, FAIZAN, Regitest2, sureshazhagai

ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals