Re tightening aluminum wire

[nizak]

Do most here re tighten aluminum conductors after they’ve been in service for awhile? A couple of times that I’ve had the opportunity to return to a job I have found I can get a bit more tightness out of it

 

[petersonra]

Do most here re tighten aluminum conductors after they’ve been in service for awhile? A couple of times that I’ve had the opportunity to return to a job I have found I can get a bit more tightness out of it

The important thing is to use a torque driver and torque it to the manufacturers specification.

 

[letgomywago]

I dint retighten unless it's loose. There are various ways to determine it's loose. Thermal camera is one.

 

[AC\DC]

They have debated this alot on this fourm.
The fact that they don't give different torque value for alum and copper shows me it's like driving ground rods make you feel good.
Maybe not that extream but it's like " close enough"

 

[electrofelon]

Ill say it: I dont really believe in torque values. Like AC/DC said, they dont give a different spec for CU vs AL, stranded or compact. I Really dont believe these values have much study or testing behind them and are just based on the set screw size. In addition, a torque wrench is just not a very accurate way to determine preload anyway. Consistent results are highly dependent on thread class, finish, and quality and I just see way too much variation in the field for them to be meaningful. In regards to the specific question, I usually like to give aluminum connection another nudge a few hours after the initial. I will also periodically give existing connections a test, but not necessarily religiously.

 

[zbang]

Unless you have a strain gauge to see how tight the connection, the torque value is as good (or better) than "giving it an extra nudge"; and only one of those comes from the mfg.

Or, I figure Ilsco knows more about their lugs than I do.

 

[electrofelon]

and only one of those comes from the mfg.

Having worked in a factory setting and seeing who and how they come up with much of this stuff, and based on many manufacturers instructions / recommendations I see, really don't have a lot of faith in them honestly.

 

[electrofelon]

So just to be clear, if you are not an experienced mechanic and electrician definitely use the torque values.

 

[roger]

Bellville washers

 

[nizak]

It can take an incredibly long time for a loose service entrance connection to surface.

Years back I replaced an overhead meter socket and riser on a residence and used AL SE cable.

Many years later the same owner called and said there was an issue and would like me to take a look.

When I opened the meter base there was one of the load side lugs that was showing signs of discoloration and heat.

I’m convinced that it was my fault and that I never properly tightened that one if the three connections.

If I recall it was at least 5 years it had been in service.

I had made a loop with the conductor and had plenty of good wire to work with to remake the connection.

 

[LarryFine]

That (A,B, & C) is exactly what happens with small aluminum wires under device screws. Cycling currents, like kitchen appliances and televisions, made it happen more than steady currents.

And just to be pedantic, the spring washer maintains pressure, not torque.

 

[roger]

That (A,B, & C) is exactly what happens with small aluminum wires under device screws. Cycling currents, like kitchen appliances and televisions, made it happen more than steady currents.

And just to be pedantic, the spring washer maintains pressure, not torque.

Proper torque is at the time of installation.

 

[ramsy]

Proper torque is at the time of installation.

That sounds familiar. See my AHJ below

Scott Davis is also a CEU trainer for building officials & other IAEI members in my area.

This sheet appears in an IAEI magazine article in 2007.

Inspecting Electrical Connections for Proper Torque

iaeimagazine.org

 

[readydave8]

A few months ago working in 1990 panel, one of the 4/0 wires slid out of main breaker

Trying to resize pic so I can post it, giving up now

 

[ptonsparky]

One of our inspectors used to tug on the wires to see if they moved. It only took once before he quit doing that.

A few months ago working in 1990 panel, one of the 4/0 wires slid out of main breaker

...

The older Al alloys seemed to be softer and more prone to loosening. Loose connections also benefited from removal, brushing, application of corrosion inhibitor and then torqueing. Sometimes just retorqueing did not improve FOP testing.