twisted pair wiring

Doesn't sound like a good idea. At the very least, it lengthens the conductors resulting in more heat dissipation over the same effective length.

Why would you want to?

Sylvia.

We had this question floating around a while ago. The best guess was this was WWII surplus army field wire that they used to wire field headquarters. O/D green? House about 50-60 years old?

never seen it... except late in the day some of my romex is that way.

Phil Scott

I not sure I'd want to but was curious about its use and its effects on devices that use power wiring to communicate.

Never in a house BUT ...

A church we use to attend used it when a new building (larger than the old structure) was added on. A new service panel was placed in the new section and some HEAVY twisted cable was run to the original service panel. (I don't know whether the "old" panel was wired with neutral separate from ground.)

The work was done by a member of the church but he was a licensed professional with plenty of experience on commercial and residential work so I guess it was legal. Certainly any reasonable inspection would have showed it.

It wasn't in conduit. The only protection was the insulation on the conductors.

Stupid question. Does not deserve answer.

Unjacketed twisted pair? No.

I have seen some NM cable in which the conductore were twisted.

So why did you? :-)

On Thu, 21 Oct 2004 14:59:55 -0700 Paul Hovnanian P.E. wrote: | hfs2 wrote: |> |> Has anyone seen a house wired with twisted pair? |> Does code allow it? Is large guage wire (10 - 12 -14) |> even available? | | Unjacketed twisted pair? No. | | I have seen some NM cable in which the conductore were twisted.

Service drop cable is twisted. It hasn't seemed to cause anything funny to happen to the electricity, like making it spin.

Best comment so far. Twisted pair is for fones not outlets.

There is nothing wrong with twisting conductors unles the pitch is so short that the twist adds some conductor length. Even then, the effect would be minimal.

I think the OP was wondering if twisting conductors would cancel coupling to adjacent circuits. The answer is yes, to a degree. If a sensitive circuit was run adjacent to a branch circuit, twisting both will decrease coupling.

What would be the observable consequence of the electricity spinning?

Sylvia.

spinning?

Maybe that's what turns the wheel in your meter?

Twisted pair would have the effect of minimizing but not eliminating the electromagnetic fields that are associated with current flow.

The principle is used in microphone, line-level audio, and telephone circuits to minimize radiation and adjacent coupling to similar circuits.

For practical electrical wiring though, the downsides outweigh the advantages. Pulling large conductor twisted pair wire though conduits for example would be difficult and require additional labor. There might be some derating to increased heat that has nowhere else to go.

In the early years of this century, appliance power cords were often twisted pair.

Beachcomber

Um, that's fine, but my question related to the assertion that the electricity doesn't start spinning. Before one can be certain of this, one needs to know what one would see if it did, in order to be able to infer anything from the absence of the observation.

Not that I was being that serious.

Sylvia.

For 50/60Hz power it won't have any practical effect, though it probably could be measured (with effort).

Twisting the pair improves balance, so the degree to which balance improvement helps is what counts. At 50/60Hz the difference between twisted and non-twisted cable would be hard to measure until the length far exceeded typical distances likely to be found in household power wiring (a few hundred feet).

But as far as using the power cable for other services, such as broadband data networking, yes it would have an effect. It would increase the distance over which such a network will function. Probably not greatly, but it might be just significant enough to allow a transmitting device to be at one end of a building rather than requiring it be in a more central location to shorten the distance to the most distant receiver.

Some "fones" are connected to those "outlets".

Well sometimes, being that serious can be a good thing...

The engineers and technicians that frequent this newsgroup like precise definitions, based upon the accumulated knowledge of the measurements and observations of physical phenomena.

What do you mean by spinning? It is difficult to describe electricity scientifically. In super simple terms, it is the flow of electrons in a conductive material. It is also characterized by magnetic and electrical fields that may occur at a distance from the conductive medium.

Magnetic fields in parallel conductors with opposite, but equal currents will tend to cancel each other out, but not completely. Twisting the conductors merely alters the spatial relationship of the residual fields so that they will occur in a circular (or more properly) a spiral track.

You could argue that the electricity is spinning in the same sense that the electromagnetic fields in an AC motor are spinning...

Beachcomber

Since this type of "army" wire has about 50 twists per meter you could say the electricity was spinning at about 900 million RPM. It's lucky that the stuff coming back is going in the opposite direction and nulling out the field or it would pull all of the nails out of the wall. ;-)