Lug Torque Specs

[Jody Boehs]

Hi,

Attached below are 2 photos of some lugs that i have a few questions about. The size of these conductors is 500 KCM and they look like they're aluminum.

1. These lugs have torque marks and a '41' wrote on them. Is that 41 in-lbs or ft-lbs?

2. I am purchasing more of these lugs and the spec sheet says the Recommended Installation Torque is 375 in-lbs. Is that for the mounting bolts, the conductor lug screws, or both?

 

[Hv&Lv]

That could be the number of the person that actually torqued the connections.

The 375 in lbs is for the connector torque.

the mounting torque is dependent on what the connector is connecting to.

 

[infinity]

41 is ft/pounds. Typical for lugs with hex screws and conductors of that size is 500 in/pounds. 500/12=41.6 ft/pounds.

 

[WasGSOHM]

Typical for lugs with hex screws and conductors of that size is 500 in/pounds.

And for the OP's example, what torques would be off the wall, very unreasonable, values?

So he can just look at a number and say "No."

500 is a point estimate and I guess I'm asking for an interval estimate.

 

[infinity]

And for the OP's example, what torques would be off the wall, very unreasonable, values?

So he can just look at a number and say "No."

500 is a point estimate and I guess I'm asking for an interval estimate.

Since you quoted me I'll respond, but I have no idea what this means.
I believe that this is from Eaton:

 

[WasGSOHM]

Yeah, the specs in this image do not give a range of acceptable torque values.

 

[Jody Boehs]

Thank You. So from what I've gathered the 41 is in ft-lbs. That part makes sense. I am hoping the mounting torque specs are listed on this equipment.

 

[WasGSOHM]

I’d be good if you could estimate required torque by just looking at the connector size.

If this connection is 1 cubic inch and takes 40 pound x feet then
if someone says he torqued this to 20 or 80 pound-feet or pound-inches, you know right off the bat that something may be wrong.

I don’t know yet whether a two cubic inch connection takes 2 x 40 pound-feet.