Objectionable Current

[czars]

Is there a definition in the NEC, or elsewhere, for the term "Objectionable Current"? Article 250.6 C & D identifies what Objectionable Current isn't, but I can't find an definition of what it is.

 

[G._S._Ohm]

I can't find an definition of what it is.

That which causes fire [due to heavy current in a small conductor which probably means conductor temps over 120 C]
or
electric shock due to heavy current in a conductor [which means more than 1 V with respect to ground for almost everyone]?

 

[raider1]

That which causes fire [due to heavy current in a small conductor which probably means conductor temps over 120 C]
or
electric shock due to heavy current in a conductor [which means more than 1 V with respect to ground for almost everyone]?

That wouldn't be objectionable current as addressed in 250.6.

Objectionable current as addressed in 250.6 is mostly caused by accidental neutral current flowing on a grounding conductor. This is typically caused by an accidental or intentional neutral to ground connection downstream from the main bonding jumper or system bonding jumper.

Chris

 

[bphgravity]

There isn't and can't be a definition of objectionable current as it is determined to exist on a case by case basis. It's much like the term "workmanship". I don't know what workmanship is, but I know it when I see it...

The IEEE makes a good attempt to attribute certain electrical currents as objectionable current when they are present on grounded parts. Again, there is no value or range that stipulates current is or is not objectionable.

I would suggest if arcing (sparks) are being observed on grounded parts, or if shocks are being perceived on grounded parts, or if other electrical problems and/or hazards are present that go away by altering the grounding system, then objectionable current is likely present.

 

[Besoeker]

There isn't and can't be a definition of objectionable current as it is determined to exist on a case by case basis. It's much like the term "workmanship". I don't know what workmanship is, but I know it when I see it...

The IEEE makes a good attempt to attribute certain electrical currents as objectionable current when they are present on grounded parts. Again, there is no value or range that stipulates current is or is not objectionable.

I would suggest if arcing (sparks) are being observed on grounded parts, or if shocks are being perceived on grounded parts, or if other electrical problems and/or hazards are present that go away by altering the grounding system, then objectionable current is likely present.

I like that pragmatic approach.

 

[cripple]

Objectionable Current

I have submitted the last three code cycles a proposal to try to define Objectionable Current, and have all been rejected. My next proposal will be something like this ?Objectionable Current: objectionable current is any neutral currents flowing on the premises grounding system due to any wiring error.? hopefully if they do not like it or are tired of hearing from me and they wake up and come up with a definition.

 

[G._S._Ohm]

I have submitted the last three code cycles a proposal to try to define Objectionable Current, and have all been rejected.

Why have they rejected your proposal? The answer to this is at least as important as the first question and maybe even harder to get or impossible to get. I'm not even sure you have "standing to sue" to compel them to answer.

For sure, electricians and HOs have a financial interest in a clear answer.

Is it, then, whatever is left over after "Article 250.6 C & D identifies what Objectionable Current isn't"?

 

[iwire]

Why have they rejected your proposal? The answer to this is at least as important as the first question and maybe even harder to get or impossible to get. I'm not even sure you have "standing to sue" to compel them to answer.

Suing seems kind of extreme to get public information.

I did remove the persons name in case they want to remain nameless.

5-53 Log #1857 NEC-P05 Final Action: Reject
(250.2)
____________________________________________________________
Submitter: XXXXXXXXXXX, XXX., Santa Fe, NM

Recommendation: Add new text to 250.2 to read as follows:

Objectionable Current. Current that flows through paths other than the
intended grounded circuit conductors during normal operation of a system.

Substantiation: Objectionable current is not defined in the NEC. ANSI/IEEE
std 446-1987 has interpreted objectionable current, and states the following:
That neutral currents that flow through paths other than the intended
grounded (neutral) circuit conductors during normal operation of a system will
be deemed objectionable if they contribute to any of the following:

(1) Interference with the proper operation of equipment, devices, or systems
that are sensitive to electromagnetic interference, such as electronic equipment,
communications systems, computer systems, etc.

(2) Interference with the proper sensing and operation of ground-fault
protection equipment.

(3) Arcing of sufficient energy to ignite flammable materials.

(4) Detonation of explosives during production, storage, or testing.

(5) Overheating due to heat generated in raceways, etc., as a result of stray
current.

Panel Meeting Action: Reject

Panel Statement: The proposed definition does not match and is not
supported by the submitter’s substantiation. The definition is not appropriate,
since it is not always feasible to avoid some current flow due to inductive and
capacitive coupling within equipment and wiring systems.

Number Eligible to Vote: 15

Ballot Results: Affirmative: 15

 

[G._S._Ohm]

"since it is not always feasible to avoid some current flow due to inductive and
capacitive coupling within equipment and wiring systems."

This seems like a straw man argument to me. The proposal never said that current flow should be eliminated.

The proposal said
interference with. . .
Interference with. . .
Arcing of sufficient energy to. . .
Detonation of explosives. . .

I find this last term is vague
Overheating. . .
but the others are pretty much go/no-go.

If all parties to this are on the up and up nobody should object to having this widely known, and discussed.

 

[G._S._Ohm]

Here's what I think may be going on.

Even admitting that there is such a thing as objectionable current is bad for business, but by declaring some currents unobjectionable the NEC has kind of admitted that the other must exist. The cat is out of the bag.
So the next step is to say that nobody can really define objectionable current. It's simply beyond the present state of man's knowledge.

The parallel is for governments to admit that there is a such a thing as pollution, and then defining limits for acceptable pollution. Both are bad for business and there will be big fights over what pollution is acceptable.

Also, interference is by definition objectionable, so the NEC seems to be saying that objectionable equals unobjectionable.