2 wire vs 3 wire


Old 11-20-00, 05:37 AM
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I installed all new swiches and outlets in 1955 home--mainly for looks. All outlets I've seen have been 3 prong--old ones were 2 prong. Most wiring in home is 2 wire romex--I've been told you can't install 3 prong outlet with old 2 wire system. I'm not really worried about codes--I use common sense and safety! If one would do everything by code you could not possibly do it yourself. Anyway, could I just use a GFCI outlet in the areas that require 3 prong outlets? ie. Kith, bath, pantry, outdoors. I already paid a "Master electrician" to upgrade my service to 150amp from 60amp only because power company would not hook up to do it myself system--same system just cost me $1,000 want a waste of $. That kind of $ goes a long way for the do it yourselfer. He wanted to pull all new 3 wire romex--but I did not even want to see that cost! Finally, what does "knob and tube" look like? I think I have romex--just really old 2 wire.
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Old 11-20-00, 08:10 AM
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I challenge your assertion that code prevents DIY. I've done a lot of DIY, and it's all been 100% code. I also challenge your assertion that safety does not require code. The code is based on safety and nothing else but safety. I'm sure your common sense it good, but there may be safety considerations you haven't though of.

You have Romex if you have an outer sheathing covering insulated conductors inside. Yes, in 1955 you almost certainly got Romex without a grounding wire (although Romex is a brand name, and you might have gotten some other brand). Officially, you got "NM" cable.

So go ahead and use GFCI outlets on all circuits for which you are upgrading the outlets. It'll be code, it'll be DIY, it'll be safe, it'll be inexpensive, and it'll be easy.

Good luck.
Old 11-20-00, 11:40 AM
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I couldn't back up John Nelson strong enough in what he said.

I am an Electrical Inspector in a do it yourself County. No licensing is required in my county, yet the wiring installed and inspected by me that has been installed by even people who have never wired two wires together in their life have passed the first time inspected without any list of corrections even when they are wiring a complete three story new home. There is information available through out the world to help you meet the Code.

John is right if you don't meet the minimum requirements of the NEC then you are not even meeting the minimum safety standards accepted through out the world.

It is not that hard to research enough to know that you are meeting the minimums of the NEC. Everyone issuing replies here may not be perfect but are available to help you meet those minimum safety standards. Just ask what you need to know.

Now as for replacing your two prong receptacles with three prong receptacles, again John is right. I might try to guide you a little further with what he said. Considering the time frame that your house was wired it was common to run power to light fixtures and then branching out to the receptacles singly from that light fixture. You should not replace all receptacles on the same circuit with GFI receptacles. YOu should replace the receptacles with normal receptacles then install a GFI receptacle or breaker at the line side of that circuit. That one GFI will protect all the receptacles on that circuit. The key is finding the spot that will control the whole circuit. The most likely place to do that is to install a GFI breaker in the box that feeds that circuit or install a GFI receptacle below the panel and run the feeder to that circuit to the load side of the GFI and the wire coming from the breaker to the line side of that GFI. Whether you install GFI breakers or install the one GFI receptacle in the first connection after that breaker you are protecting all the receptacles on that circuit by that one GFI. The GFI then works as an alternative to the bare grounding wire that is not present.

Also a lot of the times an electrician can do electrical work cheaper than a do it yourselfer because that electrician doesn't have to be material twice when the wrong material is bought that can't be approved to meet the NEC. Also a lot of the times an electrician can buy the material and furnish the labor cheaper than the do it yourself person can just buy the material because of the 50% or more wholesale price they have available to them.

My experience as an electrical inspector is that many people are taught wrong or assume wrong and are proud of what the wired without knowing that they made a toaster or death trap in their own home.

This is why we encourage people to ask question in places like this forum where a skilled electrician can guide you away from making mistakes that may kill or burn down what you have worked all your life to obtain.

Just ask, many will try to help guide you for free just to try and save you setting up a wiring design that can destroy your life because you didn't know you didn't know.

Just remember wiring is something that you must not loose respect with because of the inherent dangers involved to life and property.

Good Luck

Old 11-21-00, 05:41 AM
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Thank you for the replies--you both are right--I am just bitter because the power Co would not hook up to my DIY system but if I paid an "electrician" they would. As far as the city inspection--they would not have even known about the upgrade if I didn't have to hire an electrician--who called for the inspection. I bought the house without the city inspecting it--and the wiring was a mess!! I did my own inspection and knew what I was buying--price was right. You are right about the GFCI--the breakers would be cheaper than pulling new wire and the outlets are even cheaper than the breakers--just need to spend some time figurin what feeds what--already have GFI outlets where absolutely neccessary. Buy the way I am not knocking the skilled trades--everyone must make a living--but I am in Construction management and work with very well paid union master electricians, plumbers, carpenters, etc most of these guys are clueless.
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