How often are you tighten your connections

[mobiledynamics]

How often are you tightening your connections

I was tinkering with my -gen cords and such- and decided to open up a few of my connectors 10AWG wire on L14-30 connectors, etc. I know it was tight when I made them but I was able to do about almost another full screw revolution of the screw terminal when I had them open for inspection


Had me scratching my head on this one
As I know these things were proper tight when I made them

 

[wyliesdiesels]

How do you know they were properly tightened originally? did you use a calibrated torque driver?

 

[mobiledynamics]

LOL. I actually do that with a good majority of the fasteners on the car.....

I used the calibrated fingers ....

 

[Norcal]

The proper way is to torque them to manufacturers specs, and LEAVE THEM ALONE.

 

[wyliesdiesels]

LOL. I actually do that with a good majority of the fasteners on the car.....

I used the calibrated fingers ....

no such thing

proper procedure is torque to spec and leave it alone. If its torqued to spec, it should never come loose. Retorquing can damage the conductors and cause a worse condition. only proper method is to cut used strands of wire off, strip insulation off, and terminate again to spec

 

[Ralf11]

except for relaxation or stretch of the cap screw body, or vibration in use

example: on some CV joints, you want to drive for 100 miles then re-check the torque

and it is common to check fasteners on suspension & brakes periodically at maint. intervals

 

[Ralf11]

most guys have an "iron wrist"...

but with experience you can get to where you can do a rough estimate of a torque wrench

torque wrenches aren't the most accurate way to do fasteners anyway - they are just good enough for most automotive work, certain rod bolts excepted (like Raceware)

 

[wyliesdiesels]

except for relaxation or stretch of the cap screw body, or vibration in use

example: on some CV joints, you want to drive for 100 miles then re-check the torque

and it is common to check fasteners on suspension & brakes periodically at maint. intervals

were talking about electrical not automotive

most guys have an "iron wrist"...

but with experience you can get to where you can do a rough estimate of a torque wrench

torque wrenches aren't the most accurate way to do fasteners anyway - they are just good enough for most automotive work, certain rod bolts excepted (like Raceware)

again this is about electrical NOT automotive. Also, code now requires connections to be torqued with a calibrated torque wrench and some inspectors do check the torque wrench and method.

 

[u2slow]

Cords are like that. They get moved around, coiled/recoiled, and pulled/strained in all directions. The wires themselves, and the fine strands of copper shift around.

Not everything is a 'do it once, do it right'. Many things just need upkeep.

 

[sberry]

Ya, leave connections you find loose, this sounds like a good plan. You know they were precision when they were installed thousands of cycles ago.
This is a place for some good old mechanic sense, as was stated you don't want to keep tightening and cut them off but a little snug if they are loose can be ok.

 

[sberry]

Torque wrenches are cause most amateurs for lack of better words don't get them tight enough or so tight they seize them. A bunch of this stuff comes dry, neutral bar screws squeak and seize all the time, found a panel yesterday was done recent and all I could do with special driver to get them loose.

 

[sberry]

We spray lbars with a fuzz of pen spray and lug screws and bolts get a touch of no lox. Mechanical s used to have a better feel,, they really did when engine work was so routine and a guy got lots of experience tight in and comparing against torque wrenches. I tighten 20 bolts the other day and check, 10% hi, 1 was 10 low and 18 within 5%.

 

[sberry]

By the way,, how does a bolt know if it's mechanic,, or a car or on panel,,, which is a mechanical connection. btw.

 

[alfredeneuman]

<<<<>>>>

 

[alfredeneuman]

The same is true when any electrical connection is found to be loose.
It shouldn't be retorqued. Instead it should be abandoned, the old wire should be cutoff beyond the termination, the end be restripped, and reterminated to the proper torque value.

 

[sberry]

The world would come to a stop if everyone fussed over a loose screw like that. There is a little difference in snuggling something loose tHan reefing it as tight as it can be. Different if it is damaged..
Also be different if the torque was really reliable way of gaging the compression. It's better than a wag , probably about the same as a swag. Nothing can be reliably torqued if it squeaks when it's tightened and sometimes seized trying to reverse it.
There was a forum started up by some engineer types to discuss it, probably to slow and boring to maintain but as one of those egghead said,, some will never "get it". Mechanic training is very poor in this area, they keep tring to come up with ways ti simplify it as they can't get all the chimps installing and the mfg s to do it the right same way.

 

[sberry]

Snap on torque wrench manual of old said it simple.... all values are for good clean lightly lubed threads. Nothing new, the engineers know this for over 100 yrs defining torque requirements.

 

[nadogail]

When ever I happen to open a panel with Aluminum Feeders I will put a tool on the clamp screw because I have seen the effects of "Cold Forming".

I am a firm believer in "I it ain't broke, don't fix it"

 

[vtsoundman]

Re: How often are you tightening your connections

One would be surprised to learn that it's fairly even...loose connections resulting from overtightening or over torquing electrical fasters are just as common as loose or failed connections from fasteners not being tightened enough.

A loose connection is a hot connection. The hot connection causes material deformities and will ultimately result in something bad happening.

Electrical conductor materials are copper and aluminum. They easily deform when crushed by the clamping force of a fastener. Over time, an overly crushed copper or aluminum conductor more easily deforms with thermal cycling associated with electrical loads. Very similar to what happens to metal when it is flexed too much... Eventually it's snaps or yields.

Nearly every time I've been involved in a postmortem teardown of a burned up piece of electrical equipment that may or may not have resulted in additional property or personnel damage, it is traced back to improper torque of wire beneath a fastener. One would be surprised how many times the connection was well over-torqued buy a well-meaning licensed trade person.

Generally, it is the seasoned electricians and and season technicians that are most resistant to using a torque wrench. Generally it is the seasoned technicians and seasoned electricians that are most resistant to what they think is overreach by engineers. Sometimes they are right... Engineers don't have the field experience... Fastener torque, however, is an area where they are dead wrong.



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[alfredeneuman]

From the Aluminum Association>

Do aluminum connections need to be periodically tightened to maintain a good electrical connection?

No. Connections on either aluminum or copper should not be retightened after installation following manufacturers’ installation instructions. Connector test performance requirements are based upon no retightening. NFPA 70B, Recommended Practice for Electrical Equipment Maintenance, does not call for retightening conductors.

 

[wyliesdiesels]

When ever I happen to open a panel with Aluminum Feeders I will put a tool on the clamp screw because I have seen the effects of "Cold Forming".

I am a firm believer in "I it ain't broke, don't fix it"

bad idea to retighten connections

 

[alfredeneuman]

It's pretty telling that all the electricians here say not to do it.

 

[alfredeneuman]

An infrared thermometer is a good way to tell if a connection need is failing under load because it will be hotter than the surrounding area
https://www.amazon.com/dp/B07VTPJXH9/?tag=atomicindus08-20

 

[HenryAZ]

The proper way is to torque them to manufacturers specs, and LEAVE THEM ALONE.

I just pulled the instruction/installation sheet from a new Leviton GFCI. It makes no mention of proper torque for tightening the screws. I have also searched the web, using various search terms, and still find nothing.

I have a generic torque chart for different sizes and grades of metric bolts, when lacking any other source. Is there something similar for electrical connections?

 

[alfredeneuman]

Is there something similar for electrical connections?

Yes, but it's only to be used where manufacturers fail to provide the info.

Informative Annex I Recommended Tightening Torque Tables from UL Standard 486A-B.
It's in the back of the Code book after the Chapter 9 Tables

 

[Bert_]

I've snugged them up before. I don't make a habit of it but what's worse, a loose connection or a re torqued one? Sometimes there isn't enough wire to re terminate and pulling new wire is going to be very difficult to sell.

Who's to say it was tight to begin with? I ran across loose lugs several times that were only a couple years old. Some weren't heavily loaded because it wasn't burnt. You can bet I tightened the lugs.

Blanket rules about never re torquing are dumb. Use common sense. Sometimes we loose sight of the common sense part when blindly following the code.

 

[sberry]

I gonna agree with Bert here. We are not advocating re tight in over tightened connections but I ain't leaving something sloppy loose. Some of the reasoning behind this is a bit the same as car wheels dry or lubed. They can't be consistent and now we have so many alum wheels where impacting and over tight deform the holes and causes nut seizure. Impacts are bad on alum wheels especially with **** like never seize which is over used. The specs for decades,, calls for light lube, not super slippery **** that let's the nut creep. Threads need enough lube so they don't stick under pressure during install.
John Deere has a good team h manual that describes various thread designs and demands, not just engine bolts but really most threads which apply to electric too. There are good basic experiments every new mechanic should be educated with that are magnified with pipe threads with tapers, a guy can hand screw 2 inch together dry, sticks them, some near welded with very little pressure.
Torque only means it stopped turning with certain power, doesn't mean it clamped adequate, doesn't mean it simply stopped turning due to friction, all the way to welded seizure.

 

[sberry]

Most of the fundamental principles apply and this is generalization. Now we gonna teach that all a guy needs to know about righting a bolt is a torque wrench, gonna further dumb the process and going to cause more problems rather than solve as guys get further from learning comparitive feeling.
We got called to consult why wheels were coming loose on cement trucks. Got out to look and said to the guy,, it's obvious from here the bolts are dry and dirty, fine thread jobs. The genius says, he read that lug nuts are sposed to be installed dry and they didn't want to oil them cause they worried about them coming loose and they were looking for the ultimate torque wrench.
I daid, you worried about them coming loose but they coming loose now, duh.
We had big chat and the orders came down,, try spraying them with liquid wrench, amazing stuff, loose wheel problem stopped. Had some training in school but incomplete and not totally accurate and didn't develope any understanding.

 

[Jim greengo]

I've snugged them up before. I don't make a habit of it but what's worse, a loose connection or a re torqued one? Sometimes there isn't enough wire to re terminate and pulling new wire is going to be very difficult to sell.

Who's to say it was tight to begin with? I ran across loose lugs several times that were only a couple years old. Some weren't heavily loaded because it wasn't burnt. You can bet I tightened the lugs.

Blanket rules about never re torquing are dumb. Use common sense. Sometimes we loose sight of the common sense part when blindly following the code.

What he said.

 

[sberry]

I rarely use a wire been under a screw, I snip and strip. Despite some speculation I am a fussy type, I strip, trim and we'll fit for wire nuts, real tight too. I make sure to train wire prior to packing boxes, tighten the clamps and use staples. Solid can work loosen quite easy.
To come up with a spec they must have measured deformation etc. I wonder if it's a comprimise, seems like the size and type of wire would have a lot to do with it as well as thread friction loss which is hugely variable. I say it's a swag,,, it's an estimation in application at best and some highly experienced mechanics may be as good or better than the wrench especially if they done some comparison.
I had a small engine apart a while back, something didn't feel right as I was going over and trouble shooting. The installer did it before me read the spec wrong. My feel is as good in common alum block, only time I about use the wrench is rods in those, auto for mains, rods and heads. I used it a while back on 110# heads as it's been a while and I wasn't sure of myself. .

 

[HenryAZ]

Yes, but it's only to be used where manufacturers fail to provide the info.

Informative Annex I Recommended Tightening Torque Tables from UL Standard 486A-B.
It's in the back of the Code book after the Chapter 9 Tables

Thank-you very much. Using that bolded title as a search term, I was able to find a site with that table. I've saved it off as a PDF file.

 

[MikeF2316]

So, I figured from the info on this thread that the only acceptable way to change a light switch would require cutting off the end of the wire, stripping and exposing untouched conductor. And, right on cue, an episode of Ask This Old House, the resident electrician changed a switch and dimmer in a house to the old push button style.

And he cut off the old ends! But he didn't say anything that it was required to do that by code.

P.S. I've changed dozens of switches and outlets, and I only give myself a new end when there's a reason to.

 

[Robbie B]

Re: How often are you tightening your connections

At work we have a company go through and thermal scan all our electrical connections yearly. Based off this feedback we go through any trouble spots and tighten/redo the connections. These are in control cabinets that see little if any vibration from the machines. It IS a good idea to check electrical connections every once in a while.

 

[Mr. T]

P.S. I've changed dozens of switches and outlets, and I only give myself a new end when there's a reason to.

Now take this with a grain of salt. I’m not a life long sparky, but I’ve done my share of industrial electrical work.

If it’s solid wire, on a light switch or receptacle, if the wire isn’t deformed you’re probably okay. On most residential devices you are going to strip the screw/threads before you hurt the wire.

If it’s stranded wire, you should really cut it back and terminate with fresh wire. Every strand you lose is lowering the ampacity of the wire.



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[jeffmoss26]

when I did lighting and sound work at school, frequently.
found a few miswired cables as well.

 

[sberry]

So, I figured from the info on this thread that the only acceptable way to change a light switch would require cutting off the end of the wire, stripping and exposing untouched conductor. And, right on cue, an episode of Ask This Old House, the resident electrician changed a switch and dimmer in a house to the old push button style.

And he cut off the old ends! But he didn't say anything that it was required to do that by code.

P.S. I've changed dozens of switches and outlets, and I only give myself a new end when there's a reason to.

I agree that you dont gotta do it but if stuff looks a little mushed I do it and figure any less work hardened joints are better. Not only the crimp but may have tightly folded that wire etc.

 

[Meursault74]

I agree that you dont gotta do it but if stuff looks a little mushed I do it and figure any less work hardened joints are better. Not only the crimp but may have tightly folded that wire etc.

I just watched that video. Some of the wire connections went from a loop around a screw to straight under with the screw acting as a clamp. Cutting and stripping fresh would be faster and safer than trying to straighten out the previously made loops.