Conduits for power, IC's & more.

[nightflier]

We're going to be doing some work in a wooden cabinet this weekend to install a pretty fancy surround sound system. The cabinet is a hardwood built-in unit (attached to the wall) and we will be drilling 2" holes through each shelf for the cables. We will also be installing conduits through 9" of drywall to the amps which are stored in a seperate space underneath that has 2 cooling fans built-in.

From the looks of it, we will only be able to create two paths for the cables. My initial thought was to run power through one, and everything else (IC's, video, speakers) through the other. Is that the best solution to minimize interference? Also, how far appart should both paths be?

Also, we need to purchase 10' power cables for the amps (the 6' ones don't reach), and to keep costs down, we were going to use some kind of generic cable. The amps are two 200W stereo units and a 200W 3-channel unit (Anthem MCA's). What types of specs should we be looking for in a good quality generic power cable from a hardware store?

[E-Stat]

What types of specs should we be looking for in a good quality generic power cable from a hardware store?

Most likely, you would have no qualitative choices at all. I would make my own using Belden 83803 double shielded wire and Schurter, Wattgate, or Marinco connectors available from Parts Express.

http://www.partsexpress.com/pe/pshow...42&rak=110-400

http://www.partsexpress.com/pe/pshow...53&rak=100-790

rw

[nightflier]

I hadn't thought about building my own. I'll have to give that consideration. I measured the conduit out and it's about 6.5', but that would be tight, so three 8' power cords should do it.

I really was hoping to find a decent quality molded cable w/o having to go the brand-name route, though. I was told that hospital-grade would be sufficient, but I don't know what that means exactly. By the way, the conduits we drilled are 1.5' appart. We figured that would be enough to avoid any interference from the power cords.

Does anyone know if there will be interference from running audio IC's, speaker cables, and a component video cable through the same conduit?

[E-Stat]

I really was hoping to find a decent quality molded cable w/o having to go the brand-name route, though.

A very popular inexpensive shielded cord is the Volex 17604 (part of Belden). Here's a link to one source:

Volex 17604

I was told that hospital-grade would be sufficient, but I don't know what that means exactly.

I've only heard the term "hospital grade" in context to outlets. To prevent possible combustion in an oxygen atmosphere, the ground contacts before the other pins. While that feature is of little use in the home, they also have certifiable tension on the male plugs to provide the best contact. The suckers are really stiff.

rw

[jneutron]

I hadn't thought about building my own. I'll have to give that consideration. I measured the conduit out and it's about 6.5', but that would be tight, so three 8' power cords should do it.

Power cords are rated for use in free air. Putting them into the confines of a conduit is not within the design specs of the cords. I do not recommend it.

Cheers, John

[pelly3s]

Power cords are rated for use in free air. Putting them into the confines of a conduit is not within the design specs of the cords. I do not recommend it.

Cheers, John

that doesnt make any sense to me. considering that conduit is intended for running power cabling. most decent gear uses SJO for a power cord anyways

[Resident Loser]

that doesnt make any sense to me. considering that conduit is intended for running power cabling. most decent gear uses SJO for a power cord anyways

...power cables or power cords...two very different animals...UL and your insurance company may have an opinion that differs from yours...

jimHJJ(...quite dramatically...)

[jneutron]

that doesnt make any sense to me. considering that conduit is intended for running power cabling. most decent gear uses SJO for a power cord anyways

The rating for any wire is based on the ability of the insulation to survive the heat that is generated within the wire. Most wires are rated based on the maximum temperature the wire will go to for the specified current. Insulations are temp rated, with polypropylene rated for up to 80 Centigrate, PVC up to 90-105, Kynar at 105 to 125, and FEP, Kapton, Silicon up to 200 C. (this info from manhattancdt.com/tech/carryingcapacity.htm) (got lazy, caps and www needed).

Belden, in their tech info pdf, explain the current derating needed for multiple conductors on page 16.4 of their pdf. They also specify that the ratings are based on use in still air at an ambient of 25 C. A conduit is not the same as still air. The wire temps will end up higher, and you may exceed the designed insulation temperature capability.

The Belden 83803 is designed and rated for plenum use even though I use it in free air.

A plenum is by definition, a duct which carries air, no? Plenum rated has to do with fire outgassing byproducts, not with the capacity of the wire. I believe plenum rating came about as a result of a fire which killed many Arrow company executives a while back, where the toxic fumes from insulation decomposition were carried via the HVAC ductwork the wire was pulled through, to the people who died...my memory in this regard may be suspect, of course..

Cheers, John

[E-Stat]

Power cords are rated for use in free air. Putting them into the confines of a conduit is not within the design specs of the cords.

The Belden 83803 is designed and rated for plenum use even though I use it in free air.

rw

[Resident Loser]

The Belden 83803 is designed and rated for plenum use even though I use it in free air.

rw

...just some facts...a plenum is a plenum...it is free air in a large, but confined space i.e. the return in an AC system...not a conduit, at least in the normal, everyday, electrician's sense of the word.

According to a few sites, the cable you mention is UL listed as FPLP, CMP...simply rated for use in a plenum...and the specific applications are stipulated as: fire alarm systems(which is why it's outer jacket is red), voice communications and smoke detectors, control or instrumentation,...power cords? sorry, ain't on the list...it's neither rated nor tested for such an application.

jimHJJ(...so, you pays yer money and you takes yer chances...)