Originally Posted By: bbadger This post was automatically imported from our archived forum.
wdecker wrote:
What are the guidlines for installed:
a) speaker wire
b) phone wire
c) intercom wire
d) cable TV wire
A contrator told me that, for a 6.1 home theater system with 100 watt amplifier, that 12 guage speaker wire was needed.
I thought, 'Wow, that could carry 1 20 amp, 110 service".
am I missing something. I use, at home, 18 gauge speaker wire for my 200 watt stereo system with no problems.
Any comments.
Any requirements for the laying of this wire (inside the walls).
Thanks;
There is a difference between what is required and what is 'sold' .
I have wired Real movie theaters that had THX sound systems, obviously the length of the speaker run where much longer than any home theater, and the amplifiers more powerful. 14 AWG was used.
I have also been the 'house' electrician for many concerts, Red Hot Chili Peppers, Pantara, Faith No More, White Zombie and many more. As you can imagine these bands use high quality high power equipment and again it was unusual to see larger than 14 AWG for speakers.
All that said in order to be certified '6.1' there may well be a requirement for 12 AWG.
That would be a performance standard not an NEC safety code.
The short code answer to this is home amplifier systems have class 2 or class 3 outputs. They can not put out enough continuous power to overload a 24 AWG never mind an 18 AWG and 12 AWG is a IMO a marketing device.
Bigger is better now grunt like Tim Allen.
The rest of those items phone wire, intercom wire, cable TV wire are also class 2 or class 3 items and as far as the NEC is concerned 24 AWG is enough.
But again manufactures specifications may require more.
-- Bob Badger
Electrical Construction & Maintenance
Moderator at ECN
Originally Posted By: jtedesco This post was automatically imported from our archived forum.
Quote:
ARTICLE 640 Audio Signal Processing, Amplification, and Reproduction Equipment
I. General
640.1 Scope.
This article covers equipment and wiring for audio signal generation, recording, processing, amplification and reproduction; distribution of sound; public address; speech input systems; temporary audio system installations; and electronic organs or other electronic musical instruments.
This also includes audio systems subject to Article 517, Part VI, and Articles 518, 520, 525, and 530.
FPN No. 1: Examples of permanently installed distributed audio system locations include, but are not limited to, restaurant, hotel, business office, commercial and retail sales environments, churches, and schools.
Both portable and permanently installed equipment locations include, but are not limited to, residences, auditoriums, theaters, stadiums, and movie and television studios.
Temporary installations include, but are not limited to, auditoriums, theaters, stadiums (which use both temporary and permanently installed systems), and outdoor events such as fairs, festivals, circuses, public events, and concerts.
FPN No. 2: Fire and burglary alarm signaling devices are specifically not encompassed by this article.
Originally Posted By: bbadger This post was automatically imported from our archived forum.
John a lot of this is marketing hype.
"Monster Cable" will tell you you need 8 AWG for some audio systems.
And they will charge huge money for what is 8 AWG lamp cord. 
Audiophiles are a unique bunch, one audio company sells a "Audio Rated" 120 volt 20 amp duplex receptacle for about $150.00  I will try to find a link to it.
-- Bob Badger
Electrical Construction & Maintenance
Moderator at ECN
They sell you performance you can’t see on a spectrum analyser and certainly can’t hear.
If you go into one of those high end store “listening rooms” you will hear subtle differences in all of the combinations of equipment so it is clear NONE of them are “pure” or the best ones would sound the same.
If you perceive the difference and want it, buy it but just remember in a blind test you might end up liking the bell wire better.
In general I would say to run Cat 5e (AKA Cat 6) for data, RG6 quad shield for TV, phone can be Cat 3 but it might be as easy to use the Cat 5 since you already have a spool .
Speakers, intercom etc need #16 stranded ... max, but your customer may want 1/0 1000 strand, braided, oxygen free (or is it oxygen enhanced?) copper with some special sound enhancing insulation and the customer is always right. Just be sure you mark it up accordingly. 
Originally Posted By: Joey D’Adamo This post was automatically imported from our archived forum.
Well one thing to consider is voltage drop, though… if its a long distance the bigger wire might be better.
Although 100 watts at, say 12v (arbitrarily selected) is 8.6A
where as 100 watts at 120v is.. 0.86A
Not too sure what the peak voltage would wind up being, but with speakers you get the peak load and the RMS load and what you care about is the RMS load. I don't know enough to know what it would work out to in amps, but I know that people who think low voltage can always mean small wire can be very wrong.
