On residential new construction, how close can a interior phone line be to
electrical wiring without being affected by electromagnetics? Can they
cross each other?

The "book" on phone wiring says you can run them perpendicular but not
parallel to each other. I've run them parallel in the same drilled holes in
studs for short distances with no problems


"JWJWJ" wrote in message
news:92d41fc0e2af8a99ee1153d2da99e2f9@homerepairli ve.com...
On residential new construction, how close can a interior phone line be to
electrical wiring without being affected by electromagnetics? Can they
cross each other?

Others will tell you different, but I have ran phone, cat5e and Romex all
together. In fact, when I wired my garage, the phone cable (I used cat5e
cable) was ziptied to the main run of Romex cables for the whole garage. No
problems with it at all. My phone cable is brought to my house hanging
underneath the main lines, and people want you to believe that a 120V cable
is going to cause a interference problem. nada!



"JWJWJ" wrote in message
news:92d41fc0e2af8a99ee1153d2da99e2f9@homerepairli ve.com...
On residential new construction, how close can a interior phone line be to
electrical wiring without being affected by electromagnetics? Can they
cross each other?

"J.A. Michel" wrote:

Others will tell you different, but I have ran phone, cat5e and Romex all
together. In fact, when I wired my garage, the phone cable (I used cat5e
cable) was ziptied to the main run of Romex cables for the whole garage. No
problems with it at all. My phone cable is brought to my house hanging
underneath the main lines, and people want you to believe that a 120V cable
is going to cause a interference problem. nada!

It would if you were using the old four wire, non twisted cat 0 phone
wire. Since you are using cat 5 wire which is twisted pair the twist
cancels out the common mode interference that would most certainly have
been picked up with the old untwisted wire.

As for the drop to the house which is likely non twisted drop cable, it
is not in close enough proximity to be a problem. The magnetic field
that induces interference drops off in strength rapidly with distance.

Pete C.

I realize the original post was about phone wire, but I'd be interested
to see a data analyzer hooked up to some cat 5 data cables that were
run next to electrical wires. I'd be curious as to how many dropped
packets and retransmissions due to errors would occur. The average
user might not ever notice a problem but errors like these increase
network traffic and would drive a network engineer up a wall.


Pete C. wrote:
"J.A. Michel" wrote:

Others will tell you different, but I have ran phone, cat5e and Romex all
together. In fact, when I wired my garage, the phone cable (I used cat5e
cable) was ziptied to the main run of Romex cables for the whole garage. No
problems with it at all. My phone cable is brought to my house hanging
underneath the main lines, and people want you to believe that a 120V cable
is going to cause a interference problem. nada!

It would if you were using the old four wire, non twisted cat 0 phone
wire. Since you are using cat 5 wire which is twisted pair the twist
cancels out the common mode interference that would most certainly have
been picked up with the old untwisted wire.

As for the drop to the house which is likely non twisted drop cable, it
is not in close enough proximity to be a problem. The magnetic field
that induces interference drops off in strength rapidly with distance.

Pete C.

In article om,
JWJWJ wrote:
On residential new construction, how close can a interior phone line be to
electrical wiring without being affected by electromagnetics? Can they
cross each other?

Thye can be right next to each other abd touching without any
electrical interference, but it won't meet code on safety.


--
Make it as simple as possible, but no simpler.

Larry Wasserman - Baltimore Maryland -

In article , on Fri, 24 Nov
2006 23:32:51 -0600, wrote:

In article om,
JWJWJ wrote:
On residential new construction, how close can a interior phone line be to
electrical wiring without being affected by electromagnetics? Can they
cross each other?

Thye can be right next to each other abd touching without any
electrical interference, but it won't meet code on safety.

Not sure about the interference, but you're right about not meeting
code. The NEC, in Sec. 800.133, specifies a 2 inch separation between
"communication cables" and power cables unless the cables are somehow
physically separated, such as by a conduit.

--
Seth Goodman

On Fri, 24 Nov 2006 23:32:51 -0600, ()
wrote:

In article om,
JWJWJ wrote:
On residential new construction, how close can a interior phone line be to
electrical wiring without being affected by electromagnetics? Can they
cross each other?

Thye can be right next to each other abd touching without any
electrical interference, but it won't meet code on safety.


Remember that if the is no current on the AC lines, there will be no
magnetic induced fields, even though the lines may be energized.

Since the dawn of telephone communication, crosstalk between the phone
lines (and from external sources) has always been a problem, although,
now it has been minimized due to a better understanding, and improved
materials and installation techniques resulting from scientific
developments.

The first phone lines were single conductors with a common ground like
telegraph lines and suffered from severe crosstalk and power line
interference. Multiconductor circuits, loading coils, and twisting of
conductors helped to solve the problems. Ultimately, phone lines and
switches became digital (ESS) long before the Internet became
mainstream.

Beachcomber

In article , on Sat, 25 Nov
2006 02:03:15 -0500, wrote:


Read 800.133(A)(2)exception 1, the jacket of NM cable is "separation".
The 2" refers to individual conductors.


I stand corrected.

--
Seth Goodman

In article ,
wrote:

On residential new construction, how close can a interior phone line
be to electrical wiring without being affected by electromagnetics?
Can they cross each other?

If you use twisted pair phone wire there is no limit.

Agreed. If twisted to at least Cat3, running along side a long run of romex
(for example) for the ENTIRE length of even the largest residence (rare)
presents no degradation of signal. Separation is always best but not always
practical.
--

JR

Where are ya, Ma, when
we really need ya?

In article . com,
"DerbyDad03" wrote:

I realize the original post was about phone wire, but I'd be interested
to see a data analyzer hooked up to some cat 5 data cables that were
run next to electrical wires. I'd be curious as to how many dropped
packets and retransmissions due to errors would occur. The average
user might not ever notice a problem but errors like these increase
network traffic and would drive a network engineer up a wall.

Agreed, but I think your concern is EXACTLY WHY Cat5e was developed.

I suspect that, except in isolated cases, electromagnetic interference with
Cat5e is virtually non-existent. I'd bet that you'd find more drops and
retries due to poor connections such as at routers, patch panels, and
improperly made/crimped RJ45 ends, to name a few likely spots. Just a
thought...
--

JR

Where are ya, Ma, when
we really need ya?

In article ,
says...
On Sat, 25 Nov 2006 03:23:24 -0600, Jim Redelfs
wrote:

I'd bet that you'd find more drops and
retries due to poor connections such as at routers, patch panels, and
improperly made/crimped RJ45 ends, to name a few likely spots. Just a
thought...


In my BICSI training they pointed out virtually all of the crosstalk
happens in the last inch of the run, where it is made up in the
keystones. This is usually because of poor termination practices.

Interesting. The twist rate is much larger than an inch, no? I
wouldn't think a problem with the twist in the last inch wouldn't
matter much.

--
Keith

In article ,
krw wrote:

The twist rate is much larger than an inch, no?

No.

In ethernet/Cat5 cable, the twist rate is several, full twists PER inch.
Someone more familiar with LAN cable probably knows the rate.

I wouldn't think a problem with the twist in the last
inch wouldn't matter much.

It would. ...and apparently does.

I have spoken with several techs in recent years that claim it is CRITICAL to
CONTINUE the twist ALL THE WAY to as "flush with/against" the connector as
possible.
--

JR