3 way current carrying conductor

[al hildenbrand]

I have to ask....was the device intended to be used in that way. Were there instructions?

"Is a switch intended to control the electrical connection between the conductors attached to it?"

Yes.

 

[wwhitney]

A Device "carries or controls electric energy". . . . This is the very concept of a conductor.

My copy of the 2014 NEC says:

"Device. A unit of an electrical system, other than a conductor, that carries or controls electric energy as its principal function."

So by definition a Device is not a Conductor. If a switch is a device, as is generally recognized, it is not a conductor.

Cheers, Wayne

 

[al hildenbrand]

If a switch is a device, as is generally recognized, it is not a conductor.

So, you are claiming that a "conductor" does NOT carry electric energy?

 

[wwhitney]

So, you are claiming that a "conductor" does NOT carry electric energy?

No. I am saying that the definition of Device excludes Conductors. The sets Devices and Conductors are disjoint. Which set contains Switches?

Cheers,
Wayne

 

[al hildenbrand]

So, you are claiming that a "conductor" does NOT carry electric energy?

No.

OK. Then will you agree that a conductor carries electric energy?

 

[wwhitney]

Let me add some bolding to make the relevant part of the definition clear:

"Device. A unit of an electrical system, other than a conductor, that carries or controls electric energy as its principal function."

Cheers, Wayne

 

[wwhitney]

OK. Then will you agree that a conductor carries electric energy?

Sure. But I don't agree that anything that carries electric energy is a conductor. Because a switch carries electric energy, but it is a device, not a conductor.

Cheers, Wayne

 

[al hildenbrand]

The sets Devices and Conductors are disjoint. Which set contains Switches?

Your Boolean Algebra doesn't show a distinction when it comes to carrying electric energy. To show that a switch cannot "electrically" connect two conductors, forming one of the two connections of a parallel conductor, you will have to show that a switch does not carry electric energy.

Both Devices and Conductors carry electric energy. While the Set of Devices does not intersect the Set of Conductors, BOTH Sets are contained within the Set of Apparatus that carries electric energy.

 

[wwhitney]

Both Devices and Conductors carry electric energy. While the Set of Devices does not intersect the Set of Conductors, BOTH Sets are contained within the Set of Apparatus that carries electric energy.

I agree. But 310.10(H) only applies to "Conductors" not all "Electrical Energy Carriers". No violation of 310.10(H).

On a related note, what about 240.4? Where does the NEC tell me that individual conductors of a parallel installation are exempt from 240.4 and can be protected about their ampacity?

Cheers, Wayne

 

[al hildenbrand]

But 310.10(H) only applies to "Conductors" not all "Electrical Energy Carriers". No violation of 310.10(H).

310.10(H) is not "only" about conductors, it is about conductors "electrically joined at both ends." This last quote is the part that includes stuff OUTSIDE of your Set of Conductors.

 

[wwhitney]

310.10(H) is not "only" about conductors, it is about conductors "electrically joined at both ends." This last quote is the part that includes stuff OUTSIDE of your Set of Conductors.

Nope, 310.10(H) is titled "Conductors in Parallel". That phrase "electrically joined at both ends" is just a definition (in passing) of the word parallel. It does not expand the scope of 310.10(H) to all things "electrically joined at both ends". The article only ever talks about conductors, and there is no language in the article to expand that to all "Electrical Energy Carriers".

There's a good chance I was wrong the last time we fenced, but admit it, this time it is clear cut.

Cheers, Wayne

 

[al hildenbrand]

It does not expand the scope of 310.10(H) to all things "electrically joined at both ends".

I agree that we are not talking about electrically joining both ends of a wood two by four. Or any other thing than "conductors."

But that is not what I wrote. The quote "electrically joined at both ends" does not specify the thing, or things, that effect the electrical joining.

The electrical joining can be effected by things that "carry electric energy". That's the big "Set" that contains conductors and devices and more.

 

[wwhitney]

The quote "electrically joined at both ends" does not specify the thing, or things, that effect the electrical joining. The electrical joining can be effected by things that "carry electric energy". That's the big "Set" that contains conductors and devices and more.

OK, you are correct above. I have been reading "electrically joined at both ends" to mean "at a point" (the usual situation), but I agree two ends could be electrically joined by, say, a third conductor. Thanks for taking the time to clear that up.

So, I have only two lines of reasoning left:

The switch can't be part of "electrical joining", because sometimes the connection is open. That's a little weak, as the text doesn't say "continually electrically joined". Now how about if it is a lighted switch or has some other function in addition to switching? Does a load electrically join the two conductors feeding it? How about the two ends of a coil in a transformer, are they electrically joined?

Or Exception 1 could be broadly construed to apply, but that is a stretch.

Any thoughts on 240.4 and parallel conductors?

Cheers, Wayne

 

[GoldDigger]

OK, you are correct above. I have been reading "electrically joined at both ends" to mean "at a point" (the usual situation), but I agree two ends could be electrically joined by, say, a third conductor. Thanks for taking the time to clear that up.

So, I have only two lines of reasoning left:

The switch can't be part of "electrical joining", because sometimes the connection is open. That's a little weak, as the text doesn't say "continually electrically joined". Now how about if it is a lighted switch or has some other function in addition to switching? Does a load electrically join the two conductors feeding it? How about the two ends of a coil in a transformer, are they electrically joined?

Or Exception 1 could be broadly construed to apply, but that is a stretch.

Any thoughts on 240.4 and parallel conductors?

Cheers, Wayne

"Electrically joined" cannot be understood to include joined via a load or far too many absurd situations would arise. For example the hot and neutral of any circuit would be parallel conductors since they are joined at one end by the load and at the other end by POCO supply equipment or a local SDS.

 

[wwhitney]

"Electrically joined" cannot be understood to include joined via a load or far too many absurd situations would arise. For example the hot and neutral of any circuit would be parallel conductors since they are joined at one end by the load and at the other end by POCO supply equipment or a local SDS.

I agree. So if a switch includes a light, which is a small load, does that mean it no longer "electrically joins" (assuming an unlighted switch "electrically joins")?

Cheers, Wayne

 

[GoldDigger]

I agree. So if a switch includes a light, which is a small load, does that mean it no longer "electrically joins" (assuming an unlighted switch "electrically joins")?

Cheers, Wayne

I would say no. It is neither more nor less of a join than a simple switch. And IMHO for the purposes of parallel conductor identification it does not "join"

 

[al hildenbrand]

I agree two ends could be electrically joined by, say, a third conductor.

. . . the text doesn't say "continually electrically joined".

That's a key point.

When down stream unswitched load is supplied by the continuous hot conductor in the California threeway (illustrated in Fig. 5 and Fig 6 of this thread), any current drawn by such load will experience two paths between the threeway switches when the threeway switch Commons are connected to the "always hot traveler."

This Parallel path condition is not an accident, nor is it the result of an aberration. The parallel path is an INTENDED switching state of the possible several switching states of the California Threeway.

The switching logic of the California Threeway intentionally includes a parallel state.

The question is, then, are the conductors that are parallel, and supplying unswitched power to downstream load, LARGE enough to satisfy 310.10(H)? Most of the time, no.

Exception 1 can't apply because the switching is being done directly to load, not to control devices (of loads) such as relays, etc.

 

[wwhitney]

I'm going to stick with the idea that switches don't "electrically join". Sometime they carry electrical energy, sometime they don't. "Electrically join" needs to be stronger than that.

BTW, if a switch is an Outlet, and the current passing through it is outside the Premises Wiring System, can it "electrically join"?

Cheers, Wayne

 

[al hildenbrand]

I'm going to stick with the idea that switches don't "electrically join". Sometime they carry electrical energy, sometime they don't. "Electrically join" needs to be stronger than that.

Like you said, that's weak.

BTW, if a switch is an Outlet, and the current passing through it is outside the Premises Wiring System, can it "electrically join"?

Is your desk light bulb "electrically joined" to the PoCo Generator, even though they are BOTH outside of the Premises Wiring (System)?

 

[al hildenbrand]

Thanks for the "fencing" Wayne. It's late, for me, and I have a real world AM appointment to keep.

G'nite, All.