New Circuits- Old House

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  #1  
Old 02-03-05, 02:30 PM
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New Circuits- Old House

My 1900's house has 4 types or wire (BX, Romex, older sheathed) starting with Knob & Tube. Much of it is older and frail and I had the service upgraded to 200A with a 40 slot panel installed to replace the several fuse subpanels that were there (and improperly fused). The electrician re-connected any incoming circuits to the board to their appropriate new breaker size depending on the awg of the Wire. The plan now is for me to re-wire the house upgrading wire and re-circuiting everything as it is all over the place over years of adaptation. I plan on using all 12/2 to 20 amp breakers (accept detached garage which is 10 awg to eventual sub panel and 10 awg-30 amp breaker for electric dryer). I realize there will be several dedicated circuits like 2/20 amp counter-top GFI circuits and dedicated applaince circuits. I read in another post that it is appropriate to have 1 cicuit to 1 bathroom and have lights and GFI on that circuit as long as nothing else outside (that bathroom) it is involved. Is this correct? I like the Idea of 1 circuit per room as it facilitates the managing of this while it will take some time to complete. I want it to be up to snuff and safe, but I want to be practical with time and effort at the same time..Any comments and or suggestions would be greatly appreciated...
 
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  #2  
Old 02-03-05, 02:56 PM
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Yes, you are correct about the bathroom rule.

Understand that you need a dedicated circuit for laundry appliances as well. This usually means a single circuit to the laundry room that does not include the light(s).

I don't completely agree with the one circuit per room. It's overkill in some cases and may not be enough in others. Keeping in mind the already mentioned exceptions, what are you planning on doing with kitchen lighting? It doesn't make sense to put a few lights in the kitchen on their own circuit. I would go ahead and add in some other lights.

You may also want to separate lights from receptacles in other rooms as well. You don't necessarily want a tripped breaker to leave you in the dark.
 
  #3  
Old 02-03-05, 03:05 PM
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Cool

Thanks for your comments..There is already a dedicated 10awg-30amp circuit to the dryer. I agree that the 1 per circuit is overkill. I don't have any 1 room that wouldn't comfortable fit on 1 20 amp circuit and in many cases, like you mentioned, it might be over kill. I was planning on starting with this idea and adding to light circuits (perhaps 2 small rooms with few lights & outlets o 1 curcuit). Any thoughts on window A/C units? I would like to think I don't have to run a dedicated outlet to every room as I don't know where an A/C may be in the future? The house has Ballon framing and I wonder is ther any issue with running multiple 12/2 up the same part of the wall to the attic as it is clear from basement to attic. The branch to boxes near (over) the rooms they would serve..(the attic is unfloored with scuttle acess only). Thank you again....Had I known of this forum previously it would have saved a lot of time browsing the web!!!!!
 
  #4  
Old 02-03-05, 03:34 PM
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Suppose you had two options:
  1. All of room "A" on circuit 1, and all of room "B" on circuit 2, or
  2. Half of each room on each circuit.
Consider the advantages of the first option:
  1. It's simple.
  2. You can kill all power to a room with a single stroke.
  3. You have up to 20 amps available in either room.
Consider the advantages of the second option:
  1. If one circuit goes out, you still have some power to both rooms.
  2. If you need to replace a receptacle, you still have power in that room for a light to use to do the work.
  3. You have up to 40 amps available in either room, as long as you don't want it in both rooms at the same time. In my view, this gives you considerable flexibility. If you decide to dedicate one room as a bedroom and one as a study, you can use 10 amps in your bedroom and have 30 amps for all the computer gear in your study. Or if the bedroom is cold, you could put a space heater in there with the other stuff without overload, and still be able to read or watch television in the study.
 
  #5  
Old 02-03-05, 04:32 PM
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Question re-wire

Now that I have over-come and willing to think beyond the over simplified plan of 1 room per circuit (and thanks for that), if I were to consider your example of Room A and B splitting 2 circuits, would you suggest dividing it up as follows: 1 circut shares lights for both rooms and 1 circuit shares outlets? The lights circuit would probably always be "lighter" as these are 2 small rooms. I could add some hall way light which are located right outside these rooms in the hall, correct? The oulet demands might be heavier as there might be 2 outlets in each room with computer, printer, tv, radio or typical outlet appliances...How would I consider A/C wall units in this scenerio....This is very, very helpful. Thanks..
 
  #6  
Old 02-03-05, 05:19 PM
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Receptacles often use substantially more power than lighting. So you are going to need more receptacle circuits than lighting circuits. And if you want to avoid that annoying dimming when you run the vacuum cleaner (I know it doesn't bother you, but it always bothers your spouse, especially if you're the one that did the wiring).

If you use one circuit for receptacles in both rooms, you lose many of the advantages that I outlined earlier. So I'd rather see you use two circuits for two receptacle circuits, and then put the lighting on a third circuit. As long as you have sufficient panel space, extra circuits are really pretty cheap.

If you know in advance where your air conditioner will go, run a dedicated circuit for it. If possible, pick out your air conditioner before you do the wiring so that you can plan for it exactly.
 
  #7  
Old 02-03-05, 06:03 PM
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Smile

Sorry, last follow-up....I know that recepticle circuits will have the potenial for higher demand than a lighting circuit. A lighting circuit will only include room lights (light boxes) and possibly a fan or 2. On a 20 amp circuit I would imagine (roughly speaking) that I could cover 1/2 (if not more) of the second floor with one 20 amp lighting circuit (Bathrooms will be separatley dedicated). Then given your last comments, I can return to my familiar position of 1 recepticle circuit per room (roughly). I think that covers things pretty well and then in the event a room has a window A/C, there should be enough room on the Recepticle Circuit if I were unable to plan ahead for it. That's back to the over-kill situation you spoke of earlier, but at least I have the advantage you mentioned too;lights in a room separate from outlets, in the event of a breaker trip....If you could let me know what you think..I'll leave you alone...for now. Thanks very much.
 
  #8  
Old 02-04-05, 10:24 AM
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Circuit design

I am still reading the NEC, Wiring Simplified, and Wiring a House, but so far this thread has been the most helpful on circuit design. Are there standard concepts and examples for circuit design for residential homes somewhere?
 
  #9  
Old 02-04-05, 02:06 PM
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Arrow

I haven't really seen any other than disccussions of circuit plan other than analysis based on the load (How many watts based on appliances on one circuit, for example.) Otherwise, the only other comment that has stood out is separating a room's lights from outlets. I just installed a 40 slot panel and if I do something like 1 curcuit per room (roughly) I think it is a clean thoughtfull installation. I don't mind a little overkill if it assures safety, makes sense and leaves room (on a curcuit) for whatever the future holds or whatever could be plugged into any outlet...Aside from this I will have all my necessary dedicated curuits like washing machine, Electric Dryer, Kitchen counters (2 Cuircuts), garage etc
 
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