Forming wire

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A sharp 90 stretches the insulation a little. It will affect each insulation type differently. I have not tested this but I would theorize that given a #12 awg THHN in contact with a metal enclosure with a sharp square 90 degree bend has lower resistance when tested with a megger then the same # 12 bent in a sweeping 90 degree.

Looks pretty though.
 
Bending by hand is always going to result in some recognizable curved radius to the bend, placing in a vice or other holder and hammering on the conductor to bend it will give even smaller radius that may not even be that noticeable as a curved turn and will strain the insulation and maybe even the conductor itself.

What point is considered a curved turn vs a true squared corner depends on what magnification level you wish to determine this from.
 
LennyDryden said:
Forming wire in a lighting panel at a perfect 90. Does it compromise the integrity of the insulation no matter what size it is?

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Every bend has a radius. Unless you cut the wire & weld or solder at 90 deg angles, there is some radius. Question is, what is the radius of your bend?
 
LennyDryden said:
Forming wire in a lighting panel at a perfect 90. Does it compromise the integrity of the insulation no matter what size it is?

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if there is no deformation of the wire insulation, no.

if you are bending the wires with needlenose, and there is
mechanical distortion of the wire, there will be some degradation,
but it's usually insignificant, unless there is a tear in the insulation.
 
FWIW, I recall something about surges from nearby lightning strikes do not like "corners" in conductors. It is almost like inertia, similar to a car holding a turn at a high rate or speed.

Anyway, other than that, what the others have said.
 
I used duckbill pliers with no serated edges to form a 90 degree bend on a #12 wire...I was told it was against NEC to bend it that way....I sure would like to know if it is because I can't that code to convince me otherwise.

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LennyDryden said:
I used duckbill pliers with no serated edges to form a 90 degree bend on a #12 wire...I was told it was against NEC to bend it that way....I sure would like to know if it is because I can't that code to convince me otherwise.
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AFAIK, there is no Code-imposed minimum bending radius for conductors. There is for cable.
 
LennyDryden said:
I used duckbill pliers with no serated edges to form a 90 degree bend on a #12 wire...I was told it was against NEC to bend it that way....I sure would like to know if it is because I can't that code to convince me otherwise.
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Ask who told you this for a code reference.;)
 
My superintendent who also thinks that a wet location is a car wash and nothing more. I told him that in a boiler room which has a high pressurized water system 3 drains on the floor a water main... That the sub panel should be sealed and that we should be using sealed fittings for the EMT installed.

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LennyDryden said:
This Boiler Room should be considered as a wet location which is what I did not include in my last comment.

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While respecting your desire to do quality work, a boiler room is not a wet location.

Art. 100 definition....
Location, Wet. Installations underground or in concrete
slabs or masonry in direct contact with the earth; in loca-
tions subject to saturation with water or other liquids, such
as vehicle washing areas; and in unprotected locations ex-
posed to weather.
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If the boiler is getting the electrical equipment wet then the problem is with the boiler, not the electrical.
 
ActionDave said:
While respecting your desire to do quality work, a boiler room is not a wet location.

Art. 100 definition....


If the boiler is getting the electrical equipment wet then the problem is with the boiler, not the electrical.
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That was very well stated.
+1 for moderator ActionDave :thumbsup:
 
When bending conductors into a hard 90 using needle nose pliers , it would be my observation that the pliers do as much or more damage , if any at all is done, to the insulation, than the 90 degree angle itself.
 
Smart $ said:
FWIW, I recall something about surges from nearby lightning strikes do not like "corners" in conductors. It is almost like inertia, similar to a car holding a turn at a high rate or speed.

Anyway, other than that, what the others have said.
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I think there is something in the Lightning Protection Standard that requires a radius of 9" or more for lighting protection down conductors.
 
Smart $ said:
FWIW, I recall something about surges from nearby lightning strikes do not like "corners" in conductors. It is almost like inertia, similar to a car holding a turn at a high rate or speed.

Anyway, other than that, what the others have said.
Click to expand...
I believe the issue is electric field lines. The sharper the bends, the tighter is the field potential gradient surrounding the conductor. If it is too tight and the field is very strong it can break down the dielectric of the air when the voltage on the conductor is high. I understand that this is the principle behind lightning rods; their tips are very sharp to break down the air dielectric and dissipate charge before it reaches arc strength.
 
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