Is the term "Short Circuit" undefined?

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As far as I can tell, the term "short circuit" is undefined in the NEC. It is used in many places but there is no definition of its meaning.
From other sources, I learned that a short circuit is an unintentional phase-to-phase connection.
Has anyone found a definition in the NEC?

Thanks
 

hs545

Member
A short and concise definition of shorts and opens

Short circuit = zero resistance
Open circuit = infinite resistance
 

dlhoule

Senior Member
Location
Michigan
Shockedby277v said:
where you taking your readings from??

Well if I want a short circuit, I place one lead of my meter against the other lead and I read 0 ohms.

If I want an open circuit I hold the leads apart by at least an inch, and my meter reads infinity.:p :p :p
 

MAS2006

Member
Location
Missouri
:rolleyes: Automated circuit testers fail if measurement is 10 ohms or less. So what happens when you have 15 ohms for the same test. It passes, then something else fails farther in testing. A pain to find sometimes.
So, this is definitely a short circuit, something connected to other than intended load. Not zero ohms, what about high impedance faults in radio equipment, still a connection to other than intended point. You must remember the limits of what your test equipment are, and how they work.
Meters are fine, Oscopes are better.:rolleyes:
 

MAS2006

Member
Location
Missouri
Brightest bulb it the string???

Brightest bulb it the string???

Reminds me of the lady who put her RV on cruise control and goes to back to fix a pot of tea. :rolleyes: :rolleyes:
 

dlhoule

Senior Member
Location
Michigan
Reminds me of the lady who put her RV on cruise control and goes to back to fix a pot of tea. :rolleyes: :rolleyes:

I'll have you know she did accomplish something by doing that. Now the mfg put warning stickers by the cruise control. :eek:
 

hs545

Member
iwire said:
Given that definition there is no such thing as a short circuit. ;)

All circuits 'short' or not have resistance.

Not true, working circuits have a load which is resistance.
 

iwire

Moderator
Staff member
Location
Massachusetts
hs545 said:
Not true, working circuits have a load which is resistance.

Not following you here.

In my mind an open is not a circuit.

Any closed circuit has resistance even one that is 'shorted' close to the source.
 

Jim W in Tampa

Senior Member
Location
Tampa Florida
MAS2006 said:
Reminds me of the lady who put her RV on cruise control and goes to back to fix a pot of tea. :rolleyes: :rolleyes:
Same type of thing really happened in Naples Fl many years ago.A guy set his cruise control on alligator alley (staight as a bullet) then went to back of van to take a nap.
 

izak

Senior Member
Location
Springfield, MO
i would define a 'short circuit' as one that takes a shorter path than otherwise intended.


if the circuit is 50 feet long, and has a fault 10 feet from the source, then it is a short(er) circuit
 
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