2 wire to 3 wire

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Old 04-12-16, 04:43 PM
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2 wire to 3 wire

my house is older and it is a 2 wire electrical system.I am beginning an addition to my kitchen and want to tie a 2 conductor 1 ground wire system to the existing wire.How do i wire it at my junction boxes?
 
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Old 04-12-16, 05:43 PM
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By code.... you cannot attach new grounded cable to an ungrounded circuit. You will need to run a new grounded circuit from the panel.
 
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Old 04-13-16, 11:49 AM
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You also can't modify or extend an existing ungrounded circuit due to it being a safety hazard, but technically is grandfathered under code. You can leave those circuits AS-IS or installed new grounded cabling.
 
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Old 04-15-16, 01:35 PM
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I am in the process of solving the same problem with the home my daughter just purchased.

Home is older and all wiring is 2-wire. No ground. It was code when it was built.

Of course, they have many 3-wire devices that won't work in the 2-prong outlets. Even with metal boxes, there is still no way to properly ground (i.e. adaptors) because the boxes aren't grounded to anything.

We are "lucky" in that most of the walls were covered in 2-layers of wallpaper. That means we were tearing down and replacing sheetrock anyway. With all the walls open, we had a licensed electrician friend come in and rewire everything for 3-wire grounded circuits. It was also a chance to upgrade to 200amp service and split some branch circuits.

Overkill to some, but the thought of my future grandkids and all those ungrounded circuits made me err on the side of caution.

I realize not everyone has the "luxury" of ripping out sheetrock to rewire. There is another solution that provides some protection and meets code.

Use a GFCI breaker.

If you install a GFCI breaker, you can use "3-prong" outlets. They are much more expensive than standard breakers, but still less expensive than re-wiring. I believe there may be some rules regarding labeling of the receptacles when doing this - I will leave others who are more knowledgeable to respond with details.

The point is, there is a relatively simple solution that meets code.

Note it is generally not recommended to connect an appliance (i.e. refrigerator) to a GFCI breaker. It can apparently cause the breaker to trip (turning off the fridge and spoiling food). For this, you will want to use a proper 3-wire connection.

Also note that code usually requires GFI protected outlet(s) in a kitchen. (I believe you need a dedicated 20a GFI line for counter outlets - but I'm not a code expert, so you should verify this with a professional). You might want to see how that affects your remodeling project. Depending on what changes you make, you may be required to update your wiring and install a GFI outlet(s).
 
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Old 04-15-16, 02:17 PM
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Note it is generally not recommended to connect an appliance (i.e. refrigerator) to a GFCI breaker.
Obsolete recommendation. Receptacles in kitchens are required to be GFCI and that is what refrigerators are usually plugged into.
 
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Old 04-15-16, 02:37 PM
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Adding GFCI protection to an ungrounded circuit does allow you to replace the old 2-prong receptacle with 3-prong receptacles (provided they are labeled NO EQUIPMENT GROUND); however it still does not allow you to extend or modify that circuit. The old 2 wire circuit wiring itself must be left as-is or replaced. In some cases you are allowed to add retrofit ground wires to existing 2-wire circuits, but not only is this just as much as rewiring, but it still does not allow expansion of the old circuit.
 
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Old 04-15-16, 06:31 PM
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I'm not challenging your claim, but everything I have read indicates code does not require that a refrigerator in a residential kitchen have a GFCI. The reasoning seems to be that the fridge is plugged into a dedicated non-accessible outlet. (Although GFCI seems to be required for refrigerators in all other locations.)

In some cases it is difficult to determine the date of an "expert's" claim on the topic. When was this changed and where in the NEC can I find the reference? Again, not a challenge - I simply want to have a point of reference.

I am going to see what the electricians have done at my daughter's home with this. I believe they have an inspector coming tomorrow. I know the refrigerator has a new grounded line, but don't know if they installed a GFCI outlet for it. (Based on your statement, I imagine they did).
 
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Old 04-15-16, 08:37 PM
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The gfi requirements can be found in Article 210 of the National Electrical Code. You can also call your local building officials.
 
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Old 04-15-16, 09:14 PM
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Yeah... been looking for references to the current NEC article 210. All I could find is the requirement for GFCI outlets within 6ft of the sink. Nothing about a refrigerator requirement. Some articles mention a problem with a GFCI receptacle on a refrigerator... as those outlets are usually inaccessible, it leads to a lack of testing and maintenance of the GFCI function.

I'll likely see the local inspector tomorrow. Will ask him about it.

Then again, according to State Adoptions - Electrical Code Coalition my state (NY) is still on the 2008 code, so I imagine my inspector's answer will be based on that. Pretty interesting map - I didn't realize the "national" code wasn't so national.

Look like the OP is in MS, which the chart claims has no statewide NEC adoption. So how does that work? Does the state have its own code? Are places like that usually more or less strict than NEC? Never realized there were states that didn't follow NEC code.
 
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