Torque wrenches

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zog

Senior Member
Location
Charlotte, NC
42 ft-lbs wont get you very far for most switchgear connections, are you following ANSI standards for torque values? A SAE 7 grade 7/16" bolt require 44 ft-lbs. An SAE 5 grade 1/2" bolt is 48 ft-lbs.
 

infinity

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Location
New Jersey
Occupation
Journeyman Electrician
42 ft-lbs wont get you very far for most switchgear connections, are you following ANSI standards for torque values? A SAE 7 grade 7/16" bolt require 44 ft-lbs. An SAE 5 grade 1/2" bolt is 48 ft-lbs.


I guess that it also depends on whether you're torquing bolts or lugs. Most of our switchgear comes with the lugs already installed so generally we only torque the lugs. The biggest problem I typically see is a lack of torque information listed on the gear.
 

zog

Senior Member
Location
Charlotte, NC
The biggest problem I typically see is a lack of torque information listed on the gear.

Yep, thats a problem, thats why NETA put the values in the ATS, most switchgear will be commisioned by someone else and they are required to check all those connections anyways. Problem is if they were over-torqued in the first place.
 

brian john

Senior Member
Location
Leesburg, VA
I guess that it also depends on whether you're torquing bolts or lugs. Most of our switchgear comes with the lugs already installed so generally we only torque the lugs. The biggest problem I typically see is a lack of torque information listed on the gear.

After shipping from Mexico on boats then cranes, then trucks, then riggers, I would suggest verifying all connections are at a retorque value.
 

ohmhead

Senior Member
Location
ORLANDO FLA
Back in the dark ages when I decided to use torque wrenches, bending beam were not only less expensive but more accurate than other styles. Field calibration is very easy. Other than always having to be able to see the pointer when using, why would I want to spend dollars on something that needs to be calibrated every time it falls off the front seat of my pickup?

Well in most switchgear i dont see one using a wishbone type TW , tight spaces we use a small short dial gauge TW.

We were schooled never to use any added universal sockets or extensions on or when using a torque wrench.comments?

Each job we do you have to show the engineer and the electical inspector the stamp & date it was calibrated or your not passing inspection.

Then they randomly pick lugs to test. you adjust your wrench and it must snap or you dont pass . Each lug is marked with a black dot to let everyone know its been torqued .

Some inspectors look at our work and never ask to test but it better look good and neat they know our work and reputation kinda so we get to just bull S--- mostly . take care best to yas
 

jrannis

Senior Member
42 ft-lbs wont get you very far for most switchgear connections, are you following ANSI standards for torque values? A SAE 7 grade 7/16" bolt require 44 ft-lbs. An SAE 5 grade 1/2" bolt is 48 ft-lbs.

I follow the labels in the gear. I was commenting on the cable hex connections not the nuts and bolts the lugs are under.
 
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