elec, cat5e and RG6 in the same wall cavity??

[ewelin]

I'm starting work on updating my place.... it's an old 2 story 2 family house. We live on the 2nd floor, my grandfather lives on the first. We have a full basement and a unfinished attic space. I plan on adding a storage room in the basement which will have a wiring closest which will contain the starting point for the whole house networking, tv and telephone. I currently have a 15x3.5" wall cavity that goes from the basements all the way to the attic. Only thing currently in it is a single hot water pipe that supplies our kitchen. I need to get the wiring from the basement to the attic and then drop them back down the center walls into each room.

I am hoping I can use this cavity to make all of my bundled wire (2 RG6 & 2 cat5e) drops. Right now there will be 4 drops with one more to be added at a later date when we remodel our kitchen. I was also hoping I could manage to run new electric wires in the same cavity to supply each of the rooms as the wiring needs updated. A lot of the rooms are on several circuits and curcuits span multiple rooms... it's a mess...

Would running the bundled wire and elec. wires in the same cavity cause an issue? I was planning on attaching the elec. wires to the left stud and keeping the bundled wire on the right stud. Should I put something between the two groups of wires or should they be far enough apart that they won't interfere with each other? If I should put something in there, what would be the recommendations? Right now the cavity is open on both my grandfather's floor and our as I've been cleaning up the existing wiring that's in there. Was some old telephone and OTA antenna controller wires. I plan to start running the bundled wire later this week and the elec. would start sometime in Jan or Feb. I plan to close up the cavity on both floors prior to the wiring being completed but will have two 14x14 access points, one on each floor.

Thanks in advance for any guidance.

 

[pete_c]

Personally my runs in the attic run parallel about 2 feet from the electrical conduit. The low voltage is on one side of the roof peak and down about a foot while the electrical / lights runs parallel on the opposite side and down a foot. In the basement I pretty much stayed away from the electrical conduit except for a few places. My main runs from the basement to the attic are not near electrical conduit nor any outlets. My wired bundles consist of RG6, CAT5, shielded 22/2, 16/4, rapidrun cables, etc. My 42" media panel is about 3 feet from the fuse panel. Found the following relating to low voltage alarm wiring surfing:

"NEC requires a minimum 2" separation between high voltage (110VAC) and low voltage (communication grade) cabling. If you're running
communication grade wire down a wall which also happens to have a lightswitch, it's going to be darn difficult to maintain that separation
unless you cut out the dry wall and physically staple the wire. Most alarm installers recognize this and will use separate wall entry points from any AC wiring that's terminated or run in the same wall cavity. Electrical inspectors will look for this. They don't bring the X-Ray equipment out to ensure any wiring you've run inside the wall complies with NEC."

 

[lorenkoeman]

I think you will be fine if you are attaching each to seperate sides of the stud bay. What makes me a bit nervous is that it sounds like it is almost all of your low voltage wiring. If you wanted to go with a "belt and suspenders" approach, you might consider putting the high voltage wiring inside EMT (M for metallic) I would be 100% sure a 12-14" seperation would not be a problem then. Of course check your local codes about running EMT inside a wall cavity, but I believe this should be fine.

 

[pete_c]

I have EMT thru the whole house. What I noticed is that the electrician wired box to box with separate runs to the fuse panel. IE In the kitchen the main counter outlet power comes to a box with a GFI. From the GFI outlet it goes to 7 duplex outlets. The same method for the bathrooms. My RF low voltage cabling is all insulated. My speaker runs (16/4) are not but I do not hear any hum or extraneous noise in my 8 zones. I don't have any network issues. In the basement I used PVC pipe hangers (think they are for 4" or 6" pipes). These are cheap and connect to the ceiling joist either perpendicular or parallel. The run from the basement to the second floor attic has three access panels and I leave one Cat5 pull in place to pull more wire. Two of the access panels are part of the 8-Zone sound in the home. One is a 2' X 16" access panel. The cover is framed trim glued to the drywall that was removed. It is all painted the same color as the room and uses two screws to be held in place. I go slow when pulling cable running from one floor to the other pulling only a few feet at a time. In my older home I did a cable run in a similar manner from the basement to the 2nd floor attic. This run was one cavity over from the two furnace stacks (which were double insulated). The access panel was in a closet and it opened to the back of the furnace unit which was also in a closet.

 

[ewelin]

I think you will be fine if you are attaching each to seperate sides of the stud bay. What makes me a bit nervous is that it sounds like it is almost all of your low voltage wiring.

Yes, this would be all of my low voltage wiring. On our 2nd floor we have 2 bedrooms, living room, dining room, kitchen and bathroom. I plan on doing one drop to living room, dining room, and the two bedrooms with a future drop to the kitchen when we remodel. This is the cable I'm using for each drop:
http://www.smarthome.com/868261J/2-Cat-5e-...ax-Cable/p.aspx

I'm not sure how many electrical wires will go though that cavity... I'm guessing probably a 15 after we finish the kitchen remodel.

 

[dfeller]

I've done an obnoxious amount of pre-wire in my CI days (now turned equipment manufacturer), but the rule of thumb I always used was - no parallels less than 18" and even at that for no more than 10'.

The suggestion above to use metal conduit is the right one to keep emi down - you are essentially building a farrady cage aroudn the electrical. Keep in mind that you cannot jsut run romex inside a conduit as that violates all kinds of codes. You will need to put a box at the top and bottom and consult an electrician to meet codes in your area. As long as the boxes are properly grounded (connection to the safety ground on each end), you will reduce EMI significantly.

If you can, running cat6 will also help because of the extra shield.
And, strange as it sounds, any wire not already in its own outer shield (zip wire for instance) put a twist on it as it runs up the wall...

Parts of this are overkill, but using these "rules" I've never run into extra hum.

I put a lot of this into the chapter on "the actual pull" - see ebook reference in signature, althoguh the book is not done, the section you need is there.

Good luck

 

[Sandpiper]

Would running the bundled wire and elec. wires in the same cavity cause an issue?

In short, no. NEC article 800.113(A)(2) does say to keep communication conductors 2 inches from conductors for electric light, power, and other circuits; however, in the next paragraph there is an exception........Where the power conductor is of type non-metallic sheathed among others....non-metallic sheathed is what we call Romex.

The only real reason to keep any separation between 120VAC and CAT5 is for noise immumity for the communication circuits. Good practice is to keep at least 2 inches away but many argue that 6 to 24 inches is needed. It depends on the circumstances. As a professional alarm installer, I see many many cat 5 cables stuffed in the same holes as the electrical wires are in. I do not recommend this, but if they are in the same cavity that should normally be no problem at all. Just try your best to keep some separation.

 

[ewelin]

Thanks for the feedback everyone... The elec. will be done by a contractor friend of mine, but he hasn't done much low voltage stuff. He said by code, I would be all set, but I wasn't sure about interference... I do plan to attach the wires to the studs of the cavity to provide as much space between the two groups of wires as possible.

 

[mustangcoupe]

If you can, running cat6 will also help because of the extra shield.

David,

I am not sure what you mean by it's shield... Cat 6 comes in a shielded and unshielded versions. and the reason unshielded cat 6 does better then say cat 5 is because of the number of twists per inch of the pairs and the overall bundle. if using shielded cable you need to ground the foil shield at atleast one end (sometimes both will cause more problems because of ground loops)