What to do with old 2-wire cable?

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  #1  
Old 02-14-07, 02:31 PM
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What to do with old 2-wire cable?

I am thinking about having my old 60 amp fuse panel upgraded to 100 amp breaker type panel. All of the existing branch circuits are the old 2-wire with no ground. Do all of these circuits need to be changed out when the service panel is upgraded?

Thanks,
 
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  #2  
Old 02-14-07, 02:54 PM
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Code and inspection-wise, no. When you do a panel/service upgrade, you only need to upgrade the panel, meter, and service entrance. The rest of the circuits can remain as-is.

Though it would be a good time to evaluate your current requirements. It may be a good time to run a new grounded circuit for a computer or home theater, or upgrade the kitchen circuits that tend to trip, etc. Especially if you have an electrician already in the house.

-Mike
 
  #3  
Old 02-14-07, 04:13 PM
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Unless you have a very small house, consider going to 150 or 200 amps instead of only to 100. The incremental cost is not that large, and usually well worth it. Very few builders are supplying less than 200 amps in new homes these days.

Replacing all the wiring in a house is usually prohibitively expensive. If the old wiring is still in good shape, you can leave it as is. Run new circuits only where you need grounding (washing machines, refrigerators, electronic equipment). Rather than replacing circuits, think instead of adding circuits.
 
  #4  
Old 02-20-07, 02:46 PM
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Thanks for the reply, I will just have the electrician change out the panel and then I can run new circuits as i need them.
 
  #5  
Old 02-28-07, 10:18 AM
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Good message - glad I found it.

I'm buying an 1950's 850 sqft house with a crawl space, and I'm definitely having everything 'from the pole to the box' (including the box replaced). Before I have that done, I'm planning to replace all wires that go to outlets with grounded wires and leave 10 extra feet or so. When they put in the new box, the new wires will be there, labeled and ready to go into the new box. I like being able to do all this before I have to live there :-)

So - what size wire should I use- should I do the whole house in 10/3, for example? In my current house, the kitchen outlets (5 of them) are on a circuit with a 20amp breaker while most bedroom circuits have a 15amp breaker. I assume that heavier guage wire is used for this kitchen circuit. I just assume make every circuit a more 'powerful' circuit.

If using 10/3 wheren i don't 'need' it is overkill, is it overkill b/c I'm paying more for wire or does bigger wire (assuming the same amount of things plugged into the circuit) use more electricity? I don't mind the upfront cost but if I'm 'wasting' electricity then I'd care.

For the light switches, the 2-wirw issue doesn't matter like it does for the outlets, right? I wasn't planning on messing with them if I could help it.

Thanks,

Chris
 
  #6  
Old 02-28-07, 11:26 AM
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Originally Posted by Chrisatunc View Post
Good message - glad I found it.

For the light switches, the 2-wirw issue doesn't matter like it does for the outlets, right? I wasn't planning on messing with them if I could help it.

Thanks,

Chris
I would think it would matter. Light fixtures could short out. I'm of the mind of better safe than sorry.


I did what you're doing. I replaced my old 60 amp box with a 200 amp box professionally and then started switching out plugs in each room slowly myself. Dropping cable from the attic is pretty straight forward as is wiring (except for 3 way switches sometimes argh!). Apparently code here is to have a plug every 10 feet which none of my rooms had so I also needed to add more plugs.

One of the problems with older wiring is that a lot of it seems to be shared more than should be. My upstairs circuit is on a single cable for lights 4 and 7 outlets (including the bathroom!) which isn't enough. I added 4 new circuits so I can safely use computers, infloor heating and all sorts of electronic toys
 
  #7  
Old 02-28-07, 12:12 PM
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10/3 is way overkill. It'll be a waste of both money and effort.

I'd run 12/2 to all the receptacles. That's already somewhat overkill.

Although 14/2 is enough for the lighting, I'd run 12/2 there too. Running new wiring for receptacles is more important than new wiring for lighting, but it's good for lighting too. You'll likely find that your receptacles and lighting are on the same circuits anyway, and your receptacle wiring might even go through the lighting and switch boxes.

While you're doing all this, consider a number of other upgrades, such as more outlets and more circuits. If you run new wiring from switches to ceilings, consider using 12/3 rather than 12/2 to allow for future ceiling fans.

Don't rush into this. Read several books on home wiring and spend considerable time planning. You'll be going to a lot of work and expense, so you want to get the most out of it. And of course you'll want to follow code, so you should read up on the code too (the green paperback, "Wiring Simplified", will tell you almost everything you need to know about code--read every single word in it, except maybe the chapter on farm wiring).
 
  #8  
Old 02-28-07, 12:18 PM
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Using 10/3 is overkill on two points.

First, what do you intend to do with the extra conductor? 12-2 or 14-2 will do just fine.

Second, 15 amp circuits need 14 gage wire. 20 amp circuits need 12 gage wire. Using larger wire is okay, and it will reduce voltage drop. However, on short runs in a residence that are not heavily used, the savings in electric cost because of reduced voltage drop will be negligible.

Now, for your plans. With what you are suggesting, you need to do much more than just replace wires. Older homes are usually not up to code in more ways than just ungrounded circuits. They usually have fewer circuits than are required by code, have combined loads that are no longer allowed to be combined, and have fewer receptacles than required. The work you are proposing requires that you bring ALL of these items up to current code, at least for the rooms you are working on.

You certainly can do this, but it requires much more than any of us can easily tell you here. It requires that you fully understand the code and that you plan accordingly. I suggest starting with at least three books on home wiring.. After you read them, post back with specific question and we can help.

In my opinion, a much better solution would be for you to ADD new circuits where necessary, and only replace circuits that need to be replaced.

One final caution. The electrician you hire for the new panel may not want to attach any new circuits he or she did not run. Make sure you know exactly what he or she will allow before doing any work yourself.
 
  #9  
Old 02-28-07, 12:54 PM
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Thank you thank you thank you for the advice/insight.

I had meant 10/2 in my prevous post; sorry for the confusion.

One other question (for now): When determining whether to create a new circuit as a 15amp or a 20amp, should I be considering the *number* of devices that will typicaly be plugged into that circuit or should i focus on the amount that each device draws?

I like the idea of doing one room at a time; if I decide I'm willing to be the one to attach the wire to the back of the box then that should be the ticket. In the meantime, I like the idea of the electrician doing that. Thanks for the tip about them perhaps not wanting to attach my wiring.

-Chris
 
  #10  
Old 02-28-07, 01:10 PM
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Some circuits must be 20 amp by code. These include:

The laundry room circuit (only receptacle, no lights allowed).

The kitchen "small appliance" circuits (again, non lights allowed).

The bathroom circuits. Can have bathroom lights and fan if they serve a single bathroom only.

Other circuits have additional requirements. For example, the bedroom circuits must be AFCI protected.

For other circuits, base the number of receptacles and/or lights on the intended use.

Many people (myself included) recommend a single 20 amp circuit for the computer. Another single 20 amp circuit for the entertainment center.

Many people also recommend hard wired lights on separate circuits so that a tripped circuit breaker on a receptacle does not leave you in the dark.
 
  #11  
Old 02-28-07, 02:08 PM
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Originally Posted by racraft View Post
Some circuits must be 20 amp by code. These include:


The bathroom circuits. Can have bathroom lights and fan if they serve a single bathroom only.

Is 14/3 wiring considered ok to run at 20 amps? Or should one use 12/3 for such circuits for bathroom use?
 
  #12  
Old 02-28-07, 02:16 PM
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12-2 is the proper cable.

Please buy and read several books on home wiring. Your lack of knowledge will make the job next to impossible until you learn more.
 
  #13  
Old 02-28-07, 03:59 PM
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Originally Posted by racraft View Post
12-2 is the proper cable.

Please buy and read several books on home wiring. Your lack of knowledge will make the job next to impossible until you learn more.


Let me explain why I asked. I was thinking of running 14/3 with a double pole 15 (30 total) amp breaker. I orginally thought that if a 14/2 gauge wire is fine with 15 amps why couldn't I run 30 amps with 14/3.

But after realizing no one does this I figured it was due to heat so I won't try. It's just that there isn't much online/in my home wiring books (Black and Decker) explaining why. I'd rather know why than just simply being told 'no'.


Edit: of course after making the statement about heat I find out using 2 hot wires out of phase of each other with a shared neutral is fine. I just didn't know the term I wanted.
 

Last edited by badmana; 02-28-07 at 05:47 PM.
  #14  
Old 02-28-07, 06:36 PM
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120 volt branch circuits are limited to no more than 20 amps. It has nothing to do with heat. It has everything to do with safety. The idea is to limit the power available to a device in the event of a failure.

Yes, you could use 14-3 and use two breakers from different legs of your incoming 240 volts. This is called a multi-wire circuit. Multi-wire circuits are not common in residential settings because they tend to confuse people. They have very specific requirements for use and device connection, and some people don't bother to learn these requirements or think they can just grab any two breakers in their panel. This leads to an unsafe setup which may be a life safety hazard.

Start with the book "Wiring Simplified." It will tell you all the basics. You can then go to any number of books. Browse them at any home store, or go to the library and look at them.
 
  #15  
Old 02-28-07, 07:26 PM
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Trust me on this. This is the best advice you will get all year. You absolutely positively cannot do this job without first reading every single word in the book "Wiring Simplified". If your local home center doesn't have it (it's often sold hanging from a hook in the electrical aisle), you can buy it from Amazon. It's under ten bucks.
 
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