professional electricians out there? (not RV related)

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Isaac-1

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This is not directly RV related, this question is coming from someone with a bit of an engineering background.  Why is it the Electricians ignore torque specifications for screws, and almost always over tighten them, often to the breaking point?    I had to replace a wire going to a breaker today (30 amp to a  water heater), only to find that the professional electrician who had replaced the breaker box a few years ago had over tightened the flat head part of a flat / square drive screw to the point of snapping off half the head on one of the hot lines.  Thankfully I had a set of square drive bits, and was (barely) able to get the screw loose with it as it was starting to strip out.
 

John From Detroit

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Davison Michigan
COpper wires are round. over time when clamped they become oval. over tightening means they remain tight...longer...  I have never broken the head on one of those screws but I do tighten them... Tight.

ALso I'm fond of saying many RVers have a few screws loose.. One of the screws in my power distribution panel (Breaker box) took over 3 full turns after it worked loose from teh factory tightening (In less than six months) now been tight for oh. 13.5 years after I re-tightened.. The local RV tech (whom I spoke with today on another mattter) also tightens TIGHT.

(The other matter: We were unable to locate the slide out controller when it failed.. Well I found it)
 

xrated

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"Murvil", E. TN.
Almost no professional Electrician is going to have the time to break out a torque screwdriver and torque every single wire that they terminate......it just won't happen.  One of the tricks I learned years and years ago while still in my apprenticeship is when tightening down a terminal for a bare wire connection, say in a breaker panel, after tightening, take the wire and wiggle it back and forth and side to side several times.  Obviously not to the point of bending it in a 90 degree angle or anything like that, but back and forth several times.  After you do that, I can almost guarantee that you will get another 1/2 to 3/4 of a turn on the screw.  Obviously we aren't talking Romex and solid wire here, but stranded will yield those results.  End product is that the wire is now formed to the shape of the terminal inside and over the heating/cooling off that the wire normally has when in use, it most likely will not come loose in the terminal.
 

Jim18655

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Nov 27, 2017
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I'm a professional electrician, 40 years in the trade. It doesn't take anymore time to tighten a lug or set screw with a torque screwdriver than with a regular screwdriver. It clicks and you stop. Wiggle the wires when needed, click and you're done. I've fixed large breakers that were tightened without a torque wrench. I used a torque wrench and never went back.
 
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sightseers

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darsben said:
In the aluminum wire era tightening was critical and was required every few years.

And,  in the aluminum wire era.......the Fire Department was required every few years.    ;D
 

jrclen

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Central Wisconsin
The national electric code requires electricians to tighten all connections to the specifications in the equipment instructions or in the listing of the equipment. Many times I've seen inspectors red tag (fail) an inspection when they ask to see the electrician's torque wrench and he or she can't produce one. There is no excuse for a highly paid professional to do lazy and sloppy work.
 

wbilotta

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Aug 1, 2011
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22 years twisting nuts and I have never broken a lug in a panel.  Sometimes corrosion will fuse a screw in place.  I tighten till I think it's tight enough and then stop.

And I have never seen an electrician break out a torque screwdriver on a jobsite. 
 
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A torque wrench is perfect for people that haven't done the task long enough to know what 'tight' feels like.
 

House Husband

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K.C.MO.
jrclen said:
The national electric code requires electricians to tighten all connections to the specifications in the equipment instructions or in the listing of the equipment. Many times I've seen inspectors red tag (fail) an inspection when they ask to see the electrician's torque wrench and he or she can't produce one. There is no excuse for a highly paid professional to do lazy and sloppy work.

The NEC can NOT require any thing and has no punitive powers........The NEC is a private origination, that only offers safety standards that can be adopted by various Governmental Organizations.

 
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sightseers

Guest
same thing with U/L...

It's a private entity,    so a municipality can not require you to have U/L approval. 
 
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