Electrical Wiring Concerns

Discussion in 'Home Theater Projects' started by Kevin-R-S, Feb 21, 2006.

  1. Kevin-R-S

    Kevin-R-S Agent

    Joined:
    Jan 5, 2006
    Messages:
    27
    Likes Received:
    0
    Couple Quick Q's regarding the electrical wiring for my HT..

    1. How important is it to run a dedicated 20amp circuit for my AV Rack. Is 15 amp not sufficient? I plan on running the following equipment of this single circuit.
    - HT AMP
    - Power Amp
    - DVD Player
    - Sat Receiver
    - HD Cable Box
    - Xbox
    - Panasonic FRONT PROJECTOR
    - RF Module Emitter
    - Computer

    2. How important is it to run a dedicated circuit for my sub? Or can I simply run it off the same circuit as my pot lights.

    Is 20 amp a little over kill or am I missing something?

    Are there any recommendations as to the type of plugs I use?

    Thanks
     
  2. Paul_C

    Paul_C Stunt Coordinator

    Joined:
    Mar 5, 2000
    Messages:
    66
    Likes Received:
    0
    Hi;

    I am not an electrician but I spent many hours reading forums like this and this is what I ended up with.

    2 - 20 amp circuits just for the av rack and projector.

    I use regular plugs because I don't have any amps that require the full 20 amps.

    You have to think in terms of what the total amperage will be for all your current and future gear. That's why I have 2 circuits. I have 20 amp circuits only because some amplifiers require that much.

    I run 2 HT's and 5 rooms with stereo speakers from this rack so I have a lot of gear.

    The requirement for a sub is that the circuit that you plug it into should be on a different leg than the rest of your gear. This is at the panel. This will make sure that you don't get a ground loop that could affect your audio gear (the dreaded 60Hz hum). Of course, I forgot to make sure that the room plugs were on a different leg. Doh...

    Remember, it is cheaper to put in extra wires now and never use them than it would be to run a circuit after drywall.

    Good luck.

    Paul.
     
  3. Kevin-R-S

    Kevin-R-S Agent

    Joined:
    Jan 5, 2006
    Messages:
    27
    Likes Received:
    0
    So if I run a 12-2 20 amp circuit to my AV rack I should be OK. I have kinda calculated my required Amperage with my electrician and the pull is only about 10-12 amps.

    My electrician says he has never had the request to run a 20 amp circuit for electronics in a home use application. He seems to think I would be crazy running 12-2 across the entire basement just for a 20amp circuit...

    Can anyone who really has a understanding of this pipe in.

    SO,

    If I run a dedicated 15 amp circuit for my SUB that should be sufficient. My electrician told me no matter what I do sometimes you cant avoid the loop interference as it will occur at the utility box regardless of separate circuits.


    Any comments?

    Thanks
     
  4. Steve Ridges

    Steve Ridges Stunt Coordinator

    Joined:
    Jul 26, 2000
    Messages:
    180
    Likes Received:
    0
    I'm in the same boat. I ran a single 15 and now that the drywall is done, I'm hoping it was enough. I added up the max draw from all the equipment and I'm @ about 17 but I don't think everything will be maxed out at one time. I guess I'll see if I trip it and if I do, I'll move the sub. If I was doing it again, I'd run a 12-2 20amp.
     
  5. Paul Padilla

    Paul Padilla Supporting Actor

    Joined:
    Jan 15, 2002
    Messages:
    767
    Likes Received:
    0
    Some local wiring codes frown upon lighting running on the same circuit as outlets so check your local codes. I would be concerned about the hum factor there as well. The new circuit should definitely be on a different leg of the 220 than the lighting.

    It's always preferable to have headroom in the electrical department. It depends on how much power the amps you list will draw, but if you have to run a line anyway, definitely make it a 20amp. The electrician shouldn't really care what kind of circuit he's running...it's the same amount of work either way. I have read approximations that say that your total power draw shouldn't exceed 80% of the circuit maximum to allow for surges...especially with amplification equipment. A couple of good explosions could leave you and your popcorn in the dark.
     
  6. Dave Driskell

    Dave Driskell Auditioning

    Joined:
    Dec 18, 2005
    Messages:
    2
    Likes Received:
    0
    Kevin

    I am currently wiring my new HT and used 5 circuits 20amps
    each, all with 12-2.

    Projector on its own circuit, Equipment rack on separate circuit, lights on circuit, and 2 circuits of outlets so I could isolate the sub if needed.

    I know, over-kill...but I'm doing all the work myself and I do not want to have the drywall up and wish I had done something else.

    I'm also running Cat5e to 4 locations, RG6 to front and rear and have 2inch pvc pipe for future upgrade to the projector.

    Good luck on your project
    [​IMG]
     
  7. Kevin-R-S

    Kevin-R-S Agent

    Joined:
    Jan 5, 2006
    Messages:
    27
    Likes Received:
    0
    Thanks for all the input guys.

    After many discussions with some local HT experts at Advance Electronics, and some discussions with my electrician I have concluded the following.

    1. The electrician will run what ever I ask him to... He could care less what type of wire he is pulling. He warned me though that most household equipment is not rated for 20amp circuit which runs alot hotter than 15 amp and I may have issues with running normal equipment on a 20amp breaker. (Not sure if this is 100% true can anyone confirm)

    2. Expert at Advance said that the most important thing is "Ground Isolation between equipment". He said that the more separate circuits you can run for the AV, Projector, and Sub the better. If you can have all three on separate circuits, plus the lighting and plugs on there own circuits that would be ideal. Is it over Kill, he said it may be, is it required? He said not at all. Will the average guy notice a difference in sound or video quality... He said depends on the equipment used, and the individual, and the way in which it is wired. He did note that the sub and AV rack should have there own circuits, and that for most users 15 amps will be all they need.

    So, what I have concluded is this. If you plan on spending big bucks on a High End HT Decoder, and multiple power amps such as McIntosh or Macs to power your system you will require a 20 amp breaker, other wise if you are just an average AV guy who will be running a 2000-3000 dollar power amp and receiver then you more than likely will not require a 20 amp breaker.

    The electricians take on it was this...

    DJ's, and Music guys who play at Weddings, or Clubs plug in a 16 gage extension cord to a 15 amp breaker and run multiple power amps that can rock a Social Hall. How much power will my "Retail HT Receiver require"

    I thought that was a good point, and since I can never see myself spending $25,000 on a McIntosh Power amp to run my HT I don't think I will be requiring a 20 amp breaker.

    I hear what you guys are all saying, but after talking with the experts I think "OVER KILL" can occur. For a average user to blow a 15 amp circuit he would have to have all his AV equipment powered up running his receiver at full crank while at the same time plug in a blender or a microwave to blow the circuit. Remember that the rating on most equipment is for maximum pull IE. if the HT receiver is rated at 8 amps thats its max pull. the average pull may only be around 3-4amps.

    My conclusions... because I know in the past I have kicked my self for not running some type of wiring before the walls got closed up is to do the following.

    I am going to run a 2 inch conduit PVC pipe down the wall of my AV rack. This way if I ever require a 20 amp circuit I will simply run it through my Drop Ceiling Tile to the pipe and down the wall which wont be all that bad. I think I may run this conduit 2" pipe on a few walls "just in case"

    Cheers
     
  8. chris_everett

    chris_everett Second Unit

    Joined:
    Jul 20, 2003
    Messages:
    403
    Likes Received:
    0


    Bullshit... In most new homes, _all_ "outlet" circuits are 20 amp. Kitchens _require_ 2 20 amp circuits per the NEC.

    Ground isolation is often confused in HT (and pro) circles. All of your grounds tie together at your service entrance panel anyway, so most ground loops are generally caused by interaction between signal lines and power lines, not just power. If you have a ground loop caused only by power lines, you need to fix the problem that's causing it, as it's probably an unsafe condition.

    However, it's best to keep electronics on one side of the panel without dimmers or motors. This may not be an issue anyway (I have dimmers throughout my house, and I have no problems) but it's best practice.

    I ran two 20 amp circuits for my theater electronics. My lighting is on a shared lighting circuit with other rooms. Even that was overkill, as one 20 amp circuit would be enough. Unless you have racks of amps, and a high power projector, your just not going to have power problems if you have _any_ dedicated circuts.
     
  9. Kevin-R-S

    Kevin-R-S Agent

    Joined:
    Jan 5, 2006
    Messages:
    27
    Likes Received:
    0


    Not sure where you live but that is not the case in my area.

    Yes in the Kitchen 20 amp service is required for appliances like a Stove. Also in utility room you require a 20 amp service for Dryer, but that is because most of those appliance call for 20 amp.

    Otherwise the rest of the house is wired in 15 amp service.

    Can anyone tell me for certain that you can run normal residential style electronic equipment which is made to run off 15 amp, on a 20 amp circuit. From what I know 20 amp wire is hotter than 15amp and you could run into heat issues with your electronics if you are running them on 20 amp circuit when they are meant to run off 15 amp.
     
  10. Paul Padilla

    Paul Padilla Supporting Actor

    Joined:
    Jan 15, 2002
    Messages:
    767
    Likes Received:
    0
    [​IMG] Huh?

    Any true electricians, correct me if I'm wrong, but 20 amp circuits are not hotter, they are heaver to safely allow for more current. 110 volts is 110 volts whether it's traveling across a 15 amp or 100 amp circuit. It makes no difference to your equipment. The amperage of a circuit determines the gague of wire to use in order to allow for higher current draw. You can (completely unsafe and against code, so never never do it) replace a 15 amp breaker with a 20 amp if the breaker is tripping. You would then be capable of drawing more than 15 amps, but would likely be building up heat in the 14 gague wire that is normally used with 15 amp circuits. 20 amp circuits require 12 gague to compensate. Higher amp requirements use heavier gague still, etc.

    20 amp rated outlets are also heavier for the same reason, they do not simply have the extra prong.
     
  11. Kevin-R-S

    Kevin-R-S Agent

    Joined:
    Jan 5, 2006
    Messages:
    27
    Likes Received:
    0


    See this is the kinda stuff I need to find out. After an afternoon chat with my electrician he explained that the only fear in running electronic equipment which is not rated for 20amps on a 20 amp circuit is that if anything were to go wrong on the circuit board of the electronics you could have a full 20 amps running through that piece of equipment which would more than likely cause the cord and other parts to melt or burn. These electronic items are meant to run with 15amp circuit's.

    Anyone else have any constructive advice...
    Thanks
     
  12. KenA

    KenA Stunt Coordinator

    Joined:
    Mar 28, 2000
    Messages:
    109
    Likes Received:
    0
    Location:
    Massapequa, NY
    Real Name:
    Ken Appell
    No single component will draw more than 15 amps. They won't even come close. The only thing that draws high current is a power amp. They may spike when they are first switched on, but you won't see too many that draw more than 7-8 amps. The issue is when you have many components on the same circuit. The current draw is cumulative.

    Just have the electrician run 12/2 wire and you can always swap out the breaker later. It costs a little more than 14/2 (for 15amp), but it will be worth it. The electrician may bitch because 12/2 is a little tougher to pull since its more stiff, but tell him to suck it up.
     
  13. KenA

    KenA Stunt Coordinator

    Joined:
    Mar 28, 2000
    Messages:
    109
    Likes Received:
    0
    Location:
    Massapequa, NY
    Real Name:
    Ken Appell
    You're in the right neighborhood. Heat is a result of power. P=AV. 120 volts at 15 amps is 1800 Watts. At 20 amps, we're talking 2400 Watts. That's a lot of heat (put your hand near a 100 Watt light bulb and multiply that by 24x). Anyway, a device will only pull the current it needs, so you won't see that kind of heat. As I've said in my previous post, current is cumulative, so if you have many devices pulling high current on a single circuit, it will get pretty hot. Lower gauge wire results in thicker wire, which reduces resistance and lowers heat. 14 gauge for 15amp, 12gauge for 20amp, 10 gauge for 30amp.

    FYI, heat is more closely related to energy, which is power (watts) x time (seconds), or Joules.
     
  14. chris_everett

    chris_everett Second Unit

    Joined:
    Jul 20, 2003
    Messages:
    403
    Likes Received:
    0


    Again, bullshit. 15 amps (1800 watts) will start a fire just fine. That's why you have a circuit breaker.
     
  15. Paul Padilla

    Paul Padilla Supporting Actor

    Joined:
    Jan 15, 2002
    Messages:
    767
    Likes Received:
    0
    Any kind of electrical device can't draw more power than it's built to, but it sort of sounds like the electrician is talking about some kind of a freak short causing an overload. I see what he's getting at, but then the same would be true for a toaster oven in your kitchen's 20 amp outlet. If it's possible, it would have to be a very strange and specific kind of defect to cause that kind of power draw. In that case it would pop the 20 amp breaker too.

    Of all the specs and power requirements on every piece of electronic gear I've ever owned, I've never seen anything recommending any particular circuit amperage. I agree that he's just bitching. Lay down the law and have him run the 20. [​IMG] Why not have him run a second at 1/2 price just for being a pain in the ass. [​IMG]
     
  16. Craig W

    Craig W Second Unit

    Joined:
    Jul 28, 1999
    Messages:
    445
    Likes Received:
    0
    I ran three 20-A circuits and one 15-A circuit.

    20A - Projector and additional wall outlets
    20A - Sub
    20A - Receiver and source components
    15A - All lighting, 8 * 75W recessed lights, 4 * 100W sconces, 2 * 50W soffit accent lights

    1800W max for a 15A and 2400W max for a 20A are theoretical maxes. You should figure a 20% safety factor so 1920A and 1440A are the respective real world maxes to be in a safe operating zone.

    Its better to be over powered than under powered. I am guessing that your electrician does not want to deal with pulling 12/2.
     
  17. Kevin-R-S

    Kevin-R-S Agent

    Joined:
    Jan 5, 2006
    Messages:
    27
    Likes Received:
    0
    This is an excellent lesson in Electrical 101.

    I appreciate all the Feedback.

    My electrician is not at all against running 12-2, he is really just one of these simpleton guys who has never had the request to run 20 amp circuits in a basement before. If anything I think he is trying to save me a few $$ on the cheaper 14-2 cable and breakers.

    I talked to him last night and I am going to have him run 1-20amp circuit to the AV rack, and 1 20amp for my subs.

    Other than that I don't think it is all that important to run the projector on its own circuit or is it. I thought as long as I don't run it on the same circuit as my lighting I shouldn't have any trouble with ground looping.

    I will more than likely run the projector off the 20amp Circuit which will power my AV rack.

    Should be more than enough power.



    This is true up in Canada also...


    Cheers Gents..
     
  18. chris_everett

    chris_everett Second Unit

    Joined:
    Jul 20, 2003
    Messages:
    403
    Likes Received:
    0
    I would agree that running your projector off of your AV rack circuit is a good call. I don't see any need for a seperate circuit.
     
  19. Craig W

    Craig W Second Unit

    Joined:
    Jul 28, 1999
    Messages:
    445
    Likes Received:
    0
    I would recommend against running a projector off any circuit that powers your other AV equipment because a projector in itself draws a significant amount of power, typically around 300W. DVD players, cable boxes and other miscellaneous source equipment don't draw much power so they won't impact your audio equipment's power demand.

    Another thing to avoid some possibilty of ground loop hum I would try to run all new circuits that power your AV system off the same line in your electrical panel.
     
  20. chris_everett

    chris_everett Second Unit

    Joined:
    Jul 20, 2003
    Messages:
    403
    Likes Received:
    0
    While it's never a _bad_ idea to run additional circuits, it will be an additional expense, and take up additional panel space for something that's not really needed. It can also be more difficult to get everything on the same side of the panel.

    I'm not saying don't do it, but consider any additional expansion that you may want to add to your panel before you get carried away.

    One thing to consider is running your "subwoofer" circuit to more than just the sub, so that you can use it's extra power to help split the load of your electronics circuit if needed.
     

Share This Page