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Default Shielding conduits

Hi,

So I've learned that electrical wires can cause 60hz interference if
running along side speaker wire or intercom Cat 5. Are there any good
shielding ideas like using some kind of shielded conduit or wrapping
wires in foil or something like that? Please help point me in the right
direction.

Thanks,

Aaron
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On 7/27/2009 5:09 PM Aaron Fude spake thus:

So I've learned that electrical wires can cause 60hz interference if
running along side speaker wire or intercom Cat 5.


Dunno about "intercom Cat 5", but for speaker wires, no, no nearby power
wires can cause 60 Hz hum. If some audiophool told you this, you have my
permission to smack him upside his head.

Regarding an intercom (I assume you're talking about something actually
used as an intercom here, not Cat 5 wiring used for something else),
either 1) nearby power lines won't cause much of a problem with hum, or
2) even if they do, it's an intercom, for chrissakes; hum comes with the
territory.


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Default Shielding conduits

On Jul 27, 7:09*pm, Aaron Fude wrote:
Hi,

So I've learned that electrical wires can cause 60hz interference if
running along side speaker wire or intercom Cat 5. Are there any good
shielding ideas like using some kind of shielded conduit or wrapping
wires in foil or something like that? Please help point me in the right
direction.

Thanks,

Aaron


In critical places like recording studios there might be issues to a
perfect sound recording, keeping wires not touching and more than 6"
distance is practiced from someone I know who builds studios. Ground
loops cause issues easily heard but wiring issues I have never heard,
my problems have been groundings.
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Default Shielding conduits

ransley wrote:
On Jul 27, 7:09 pm, Aaron Fude wrote:
Hi,

So I've learned that electrical wires can cause 60hz interference if
running along side speaker wire or intercom Cat 5. Are there any good
shielding ideas like using some kind of shielded conduit or wrapping
wires in foil or something like that? Please help point me in the right
direction.

Thanks,

Aaron


In critical places like recording studios there might be issues to a
perfect sound recording, keeping wires not touching and more than 6"
distance is practiced from someone I know who builds studios. Ground
loops cause issues easily heard but wiring issues I have never heard,
my problems have been groundings.


Ask your friend who builds recording studios what kind of
light dimmers he uses. The last studio I was in used variacs
for dimming the lights. Guess why.

TDD
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Default Shielding conduits

Aaron Fude wrote:
Hi,

So I've learned that electrical wires can cause 60hz interference if
running along side speaker wire or intercom Cat 5. Are there any good
shielding ideas like using some kind of shielded conduit or wrapping
wires in foil or something like that? Please help point me in the right
direction.

Thanks,

Aaron

While not always necessary it is generally considered good practice to
run signal and power cables in separate wall cavities. That is have
a stud between them. This will usually take care of any problems that
might develop.

Bill


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Default Shielding conduits

On Jul 27, 7:09*pm, Aaron Fude wrote:
Hi,

So I've learned that electrical wires can cause 60hz interference if
running along side speaker wire or intercom Cat 5. Are there any good
shielding ideas like using some kind of shielded conduit or wrapping
wires in foil or something like that? Please help point me in the right
direction.

Thanks,

Aaron


The speakers will be un-affected.

As for the CAT5e you can always get shileded cat5e (you'll have to use
shielded plugs/jacks too with this cable):

http://www.cablestogo.com/product.as...=303&sku=27432

Older wired intercoms are always very susceptable to hum, cat5e used
for data is not that susceptable anyway, same with cat5e used for
phones.

In most cases just run the power away from the low voltage runs, and
cross them at 90 degrees, you probably really dont need shielded cat5e
but it cant hurt.


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Default Shielding conduits

On Jul 27, 8:09*pm, Aaron Fude wrote:
Hi,

So I've learned that electrical wires can cause 60hz interference if
running along side speaker wire or intercom Cat 5. Are there any good
shielding ideas like using some kind of shielded conduit or wrapping
wires in foil or something like that? Please help point me in the right
direction.

Thanks,

Aaron


Unlearn what you have learned. You cant get away from 60 Hz noise. Cat
5 circuits use balanced differential lines that cancel induced common
mode noise, power line noise is such. Use the cable the manufacturer
reccomends for hooking it up. If the cable uses twisted pairs dont
split the pairs. Follow the directions, I have never seen one hum that
was hooked up right unless there was an electronic problem with the
unit.

Jimmie
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Default Shielding conduits

There is a constant barrage of electrical noise in this world! Cell phones,
wireless devices, radio/video transmitters, electrical lines, etc.

The thing to do is use shielded speaker wire or shielded Cat 5 wire! Then
just ground the shield at one end to prevent ground loops.

Protect the things which are sensitive to outside interference. That is much
easier.

More...
http://en.wikipedia.org/wiki/Faraday_cage



"Aaron Fude" wrote in message
Hi,

So I've learned that electrical wires can cause 60hz interference if
running along side speaker wire or intercom Cat 5. Are there any good
shielding ideas like using some kind of shielded conduit or wrapping wires
in foil or something like that? Please help point me in the right
direction.

Thanks,

Aaron



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Default Shielding conduits

On 7/28/2009 7:58 AM Bill spake thus:

There is a constant barrage of electrical noise in this world! Cell phones,
wireless devices, radio/video transmitters, electrical lines, etc.

The thing to do is use shielded speaker wire [...]


Let me stop you right there.

This is pure, unadulterated *bull*****.

There is *no way* a run of speaker wire can pick up *any* hum that would
be audible in the speakers, no matter how long or how close to power
conductors.

Leave this with the rest of the audiophool BS (monster cable,
gold-plated connectors, etc.).


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Default Shielding conduits

DA had written this in response to
http://www.thestuccocompany.com/main...ts-385987-.htm
:

Aaron Fude wrote:

Are there any good
shielding ideas like using some kind of shielded conduit or wrapping
wires in foil or something like that?


Looks like you've hit a hot button issue with some of the readers here
The post actually belongs in comp.dcom.cabling group and would have easily
generated 50-100 responses in the better days of Usenet.

Anyways, with all the advice to learn and "unlearn" that you got here I
can easily imagine your head must be spinning right now. I would throw
another point of view though: by NEC (assuming you are in the USA) you are
actually required to keep 6" distance between power and signal and you
cannot use the same outlet box for terminating them. "A stud between" rule
is actually rather extreme and in many case impractical. So, if you kept
the separation to keep your installation legal, you would have eliminated
the worst-case scenario for EMI (interference). The separation is actually
a fire protection requirement but works for EMI nevertheless.

It's rather amusing to see how many black/white opinions float around here
yet no one asked what exactly would the power cable be feeding and what
the low voltage cable will be used for, which makes all the difference. A
higher load such as an AC power cable coupled to a non-balanced audio
input cable will create the hum you would not like. EMI will not create
enough current to drive speakers directly, that's true, but if you are
amplifying the noise by coupling it onto the INPUT of your audio receiver,
you will have issues. Also, an improperly installed phone cable given
enough length will pick up some hum. By improperly I mean split pairs as
in one wire from blue pair and another from orange, for example.

So, yes, it's probably not as terrible but you should not wrap your CAT5
cable around a power cable either. In any case you'd want to pass
inspection should your township decide to check on that permit... So keep
them separate.

Cheers.

DA

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DA posted for all of us...

you
cannot use the same outlet box for terminating them.


and this!

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On Jul 28, 8:18*pm, wrote:
On 28 Jul 2009 19:54:03 GMT, (DA)
wrote:

by NEC (assuming you are in the USA) you are
actually required to keep 6" distance between power and signal


Cite that


You now you could word that request a little more politely. The
actual separation as required by the NEC is two inches.

"800.52 Installation of Communications Wires, Cables, and Equipment.
Communications wires and cables from the protector to the equipment
or, where no protector is required, communications wires and cables
attached to the outside or inside of the building shall comply with
800.52(A) through (E).

(A) Separation from Other Conductors.

(2) Other Applications. Communications wires and cables shall be
separated at least 50 mm (2 in.) from conductors of any electric
light, power, Class 1, non–power-limited fire alarm, or medium power
network-powered broadband communications circuits.
Exception No. 1: Where either (1) all of the conductors of the
electric light, power, Class 1, non–power-limited fire alarm, and
medium power network-powered broadband communications circuits are in
a raceway or in metal-sheathed, metal-clad, nonmetallic-sheathed, Type
AC, or Type UF cables, or (2) all of the conductors of communications
circuits are encased in raceway.
Exception No. 2: Where the communications wires and cables are
permanently separated from the conductors of electric light, power,
Class 1, non–power-limited fire alarm, and medium power network-
powered broadband communications circuits by a continuous and firmly
fixed nonconductor, such as porcelain tubes or flexible tubing, in
addition to the insulation on the wire."

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On Jul 28, 9:39*pm, Tekkie® wrote:
DA posted for all of us...

*you
cannot use the same outlet box for terminating them.


and this!

--
Tekkie * *Don't bother to thank me, I do this as a public service.


"800.52 Installation of Communications Wires, Cables, and Equipment.
Communications wires and cables from the protector to the equipment
or, where no protector is required, communications wires and cables
attached to the outside or inside of the building shall comply with
800.52(A) through (E).
(A) Separation from Other Conductors.
(1) In Raceways, Boxes, and Cables.
(c) Electric Light, Power, Class 1, Non–Power-Limited Fire Alarm, and
Medium Power Network-Powered Broadband Communications Circuits in
Raceways, Compartments, and Boxes. Communications conductors shall not
be placed in any raceway, compartment, outlet box, junction box, or
similar fitting with conductors of electric light, power, Class 1, non–
power-limited fire alarm or medium power network-powered broadband
communications circuits.
Exception No. 1: Where all of the conductors of electric light, power,
Class 1, non–power-limited fire alarm, and medium power network-
powered broadband communications circuits are separated from all of
the conductors of communications circuits by a barrier.
Exception No. 2: Power conductors in outlet boxes, junction boxes, or
similar fittings or compartments where such conductors are introduced
solely for power supply to communications equipment. The power circuit
conductors shall be routed within the enclosure to maintain a minimum
of 6 mm (0.25 in.) separation from the communications circuit
conductors.
Exception No. 3: As permitted by 620.36."

As you can see from the above quoted material there is a prohibition
against terminating communications circuits in the same box as power
and light conductors. Yes there are exceptions but the basic rule is
there.
--
Tom Horne
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