Strange Practices

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A/A Fuel GTX

Senior Member
Location
WI & AZ
Occupation
Electrician
I was thinking today about some of the "out of the ordinary" practices I've seen over the years. One that stands out is that I worked with a guy that when wiring a MWBC, would lay out the full length of the run on the floor. Then he would take the 3 or 4 (# 12's) and put the end of them in a drill motor, have another guy holding the wires on the other end and subsequently turn on the drill and end up with a twisted bundle of wire. He would then pull the wires into the conduit. I always thought that would violate 110.3 (5) at the very least but he never gave it a second thought. I'm sure there are a plethora of other stories out there.........
 
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wireguru

Senior Member
i saw some audio installer guys doing that. They removed the jacket from their $3.50/ft 14/8 speaker cable, chucked the wires in a drill and spun it really tight. These are guys installing $500,000 sound systems in entertainment venues. I took a scrap of the wire after they did it and stripped the insulation off. It was finely stranded and about 1/2 of the strands were broken over the 4' piece I had. I didnt bother to tell them what they were doing wrong.
 

chris kennedy

Senior Member
Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
If I may share a general construction story, years ago I was doing a large slab and the shell contractors rod-busters would drink water out of their hard hats. Guess that better than putting their lips on the nozzle.
 

JohnJ0906

Senior Member
Location
Baltimore, MD
I've heard of places where they run cable on the outside walls to feed a meter. :D:D


yikes-1.gif



No way!!




:wink:
 

ohmhead

Senior Member
Location
ORLANDO FLA
just thinking you might like to know why ?

just thinking you might like to know why ?

Well on audio or high freq stuff twisting wires is smart , The reason is it gets rid of current induced in the lines . It decrease the area of the closed loops by breaking it up into little loops meaning each twist .This decreases the strength of the flux on line and the amount of EMF induced in each alternate loop the sign changes positive than negative loop to loop canceling each other out so that no current can flow its wise to twist wiring this way .Its been done for many years .but ac 60 hertz is not worth twisting .Take care
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Well on audio or high freq stuff twisting wires is smart , The reason is it gets rid of current induced in the lines . It decrease the area of the closed loops by breaking it up into little loops meaning each twist .This decreases the strength of the flux on line and the amount of EMF induced in each alternate loop the sign changes positive than negative loop to loop canceling each other out so that no current can flow its wise to twist wiring this way .
Actually, it works by assuring that both conductors receive the same induced currents (common mode), so the differential input stage will reject the common-mode signals, and only pass the difference signal ( this is called common-mode noise rejection.)

This twisted-pair (balanced-line) results in a better singal-to-noise ratio, allowing a more-relaible and quiet signal to travel farther than with (unbalanced-line) shielded coaxial cables. This is also the basis for unshielded-twisted-pair networking cabling.

All cabling is subject to induced currents. The tighter the cable's twists-per-foot, the higher the frequency of induced noise that can be assured the cable will pick up equally in both conductors, enabling the differential input stage to reject it.
 

brian john

Senior Member
Location
Leesburg, VA
Met an electrician that ALWAYS removed the XO neutral ground bond from transformers, he said it violated the NEC to have this connection. When I explained to the end user this was wrong (I tried to explain to him this was wrong and he called me stupid) and was why there was a abnormal voltages to ground, this guy went off on me in front of the customer. I went to his boss (my customer) and explained the situation.

At a Soares grounding seminar an residential electrician ask why the manufactures shipped all those green screws with the panels. He explained he had a huge box full, from 20 years of wiring houses.
 
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wireguru

Senior Member
yes, in audio and other sensitive applications wires need to be twisted. But you need to BUY twisted wire, not spin it in a drill. When the wire is 'twisted' at the factory, its actually wrapped in a planetary function, so the conductors arent actually twisted. Twisting in a drill ddamages the wire.
 

brian john

Senior Member
Location
Leesburg, VA
yes, in audio and other sensitive applications wires need to be twisted. But you need to BUY twisted wire, not spin it in a drill. When the wire is 'twisted' at the factory, its actually wrapped in a planetary function, so the conductors aren't actually twisted. Twisting in a drill damages the wire.

You talking speaker wire or power wiring?
 

wireguru

Senior Member
You talking speaker wire or power wiring?

well it depends on the wire. Spinning some #10 thhn in a drill shouldnt do too much damage, but something thats finely stranded could sustain some damage. I have a bunch of #12 UL1015 awm, ill try sticking some in a drill.
 

wireguru

Senior Member
well it depends on the wire. Spinning some #10 thhn in a drill shouldnt do too much damage, but something thats finely stranded could sustain some damage. I have a bunch of #12 UL1015 awm, ill try sticking some in a drill.

twisting #12 UL1015 AWM wire in a drill, and twisting it so tight the insulation became deformed, caused no broken strands. A few strands did become kinked though. On the smaller awg and more finely stranded wires, i think these kinks form and the strand snaps.

RIP 3ft ea red, black 12awg UL1015 AWM. :( thats $0.48 ill never see again...
 
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