tx-codeguy
Member
- Location
- Tyler, TX, USA
Any ideas about how to determine if the torqueing requirements were met from an inspection point of view? This seems very hard to certify that this has been done correctly. Anyone dealing with this?
110.14(D) Torqueing Electrical Connections 2017 NEC
- Thread starter tx-codeguy
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jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
I have no idea how this new rule is going to work in the field.
Where I work, we gotta torque the required terminations with QA/QC guy watching.
He checks calibration sticker, required torque spec, and tool setting first and then we finish.
This works okay in a controlled setting, but gonna be a bear in field work.
Where I work, we gotta torque the required terminations with QA/QC guy watching.
He checks calibration sticker, required torque spec, and tool setting first and then we finish.
This works okay in a controlled setting, but gonna be a bear in field work.
- Occupation
- Licensed Electrician
Since you are not supposed to retorque a connection I don't see how this will be enforced in any way. I do know that most electricians over tighten connections. For me, on the jobs I've been on where we followed specs, I was surprised at how light the specs were.
I was on one job where the screw torque on all our din rail mounted terminal strips was 5 in lbs. We spent about three hundred dollars on torquing screwdrivers and dutifully torqued as we were told and then watched wires fall out of terminals every day for a whole summer. It was ridiculous.
When the wires got put back they got tightened with a plain screwdriver till snug. No big wheels complained about it at that point.
I was on one job where the screw torque on all our din rail mounted terminal strips was 5 in lbs. We spent about three hundred dollars on torquing screwdrivers and dutifully torqued as we were told and then watched wires fall out of terminals every day for a whole summer. It was ridiculous.
When the wires got put back they got tightened with a plain screwdriver till snug. No big wheels complained about it at that point.
In the nuclear power plants I have worked, any torquing considered technical specification or higher required a third-party verifier (i.e a coworker certified in torquing and as an independent verifier and not associated with the actual project at hand) or a QA person to witness. As ActionDave mentioned about not retorquing a connection, the only way it can be handled in the field is with the inspector witnessing it himself or allowing the same or similar practice as we use in nuclear.
Perhaps an avenue for a special purpose contracting... :blink:
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Torqueing has kind of sort of always been covered by 110.3(B), inspectors generally weren't wanting to witness tightening before...
Next they will want to watch you twist on every wire connector to make sure you followed instructions for installing the connector.
Next they will want to watch you twist on every wire connector to make sure you followed instructions for installing the connector.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
I agree, it has already been required for decades so I'm unsure if any inspection agency is suddenly going to expand their compliance when shifting to the 2017 NEC.
I could see it working like this: inspector breaks out his torque screwdriver and hits a few random circuit breakers if he gets all clicks then it's good. Won't do any good if everything is over-tightened but at least they're not loose. :roll:
- Location
- Windsor, CO NEC: 2017
- Occupation
- Hospital Master Electrician
In Boulder CO (and yes, I'm calling them out by name on the record and doubling down that I hope I live to see the day their building department gets hit by a meteor) they require a "Torque Report". Basically, when you're done working, you're supposed to write an essay detailing every screw involved in the job, and hand it to the inspector during inspection. That's one of the more sensible points of nonsense they require. I hope I never have to work there again.
By the way, Boulder stinks. :happyno:
By the way, Boulder stinks. :happyno:
- Occupation
- Licensed Electrician
Eastern sloper that you are you really do hate the mountains don't you?
- Location
- Windsor, CO NEC: 2017
- Occupation
- Hospital Master Electrician
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
I install a lot of control panels (8 in the last 2 months) with DIN rail mounted terminals, torque specs are 5 in lbs. I tighten with a small screwdriver (Klien TB) and then go back with a Wiha torque screwdriver, nearly all the time I get an additional 1/4 to 3/4 turn.
And on field maintenance we find a lot of loose terminals.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
I have noted that both Ideal and Klien now have new torque screwdriver kits, both around $200....
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
OK and a side note, I just had a dental implant done, the dentist used a tiny torque wrench for the 6 newton millimeter spec to tighten the screw fastening the implant.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Even if it were correctly tightened the first time, it may turn some more if one comes back later with torque wrench - only correct way is verification of the first attempt at tightening.
"Torque report"? One could easily make up a report and they may never know the difference between it and one truly based on the install. :happysad:
IMO this is starting to borderline being design specification and/or QC issue more then an issue NEC is supposed to be concerned about.
mwm1752
Senior Member
- Location
- Aspen, Colo
Electricians are getting the torque wrench & at services & panel feeders easily show the connection is properly torqued -- mark it with the sharpie & done -- as for devices that's another conversation
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
How does that assure anyone that did not witness the tightening that it was properly torqued?
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Are you saying that a properly torqued connection will eventually loosen? Doesn't that go against the concept of never re-torquing a connection that was properly torqued at installation?
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
I really don't know, but especially noticed with aluminum conductor - you can usually come back later and tighten some more, before it reaches the set point of your torque wrench again. Are we supposed to sit there indefinitely with torque wrench and pull the handle every few minutes to assure the torque remains correct?
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
I believe what you are referring to is called cold flow. The wire will continue to compress a little for awhile after torquing. This is natural and does not cause a loose connection. This movement/compression is factored in for the torque specs.
Basically, if you torque a wire to x ft-lbs and later go back and retorque to x ft-lbs you will get some amount of turn.
The problem is that now you overcompessiong the strands and damaging the conductors.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Kind of how I always understood it, does no good to continue to tighten - you just increase how much cold flow has occurred and eventually can compromise the conductor. General rule is to tighten it to correct torque during installation and then you are done, unless you do have instructions that state otherwise.
jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
That is what I was taught.
- Status