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Where do I put GFCI?

5K views 15 replies 4 participants last post by  grgryl 
#1 ·
I understand that to protect the entire circuit, the GFCI must be installed in the first receptacle of that circuit. If the existing outlet only has 2 wires (plus ground) then it must be at the end of the circuit. If it has 4 wires (plus 2 grounds) then it is in the middle or beginning of the circuit. (Hope that is correct)

For the kitchen Island breaker, I can't seem to find where the 1st receptacle of the circuit is because none of the outlets have 4 wires (see diagram). I've indicated what colored wires go to each receptacle with white, black or red dots. They all have ground wire attached (but did not put that in the diagram)

I'd rather not install a GFCI breaker; seems more complicated and little worried about safety. How can I find the 1st receptacle of the circuit?
 

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#3 ·
I don't believe there is such a thing as a split GFCI receptacle, in the case where half an outlet is switched. You would probably be better off putting in a GFCI breaker and just be done with it, don't have to worry about re-wiring the entire circuit or changing out outlets either. Plus, depending on how that switch and switched outlet is wired it should protect both halves of that outlet.
 
#10 ·
I am assuming that the switch and the outlet on the far right are in the same box. That being said, I would guess that box is where the power comes into the circuit, black wire feeding both the outlet and the switch, then continuing on the black wire feeds the un-switched half of the center outlet, and the red wire feeds the switched half, and the last box the outlet is fed by the black wire.

If and only if this is the way its laid out, you can change out the outlet in the same box as the switch and wire everything downstream of the GFCI. If the power comes into any other box though, it would be difficult to rewire with one GFCI protecting the entire circuit. If you can, take some pictures of the box in the center and the box with the switch and outlet in it. Also, tell us how many wires are in the single outlet box on the left side of your diagram.
 
#11 ·
I am assuming that the switch and the outlet on the far right are in the same box. ...............................

If and only if this is the way its laid out, you can change out the outlet in the same box as the switch and wire everything downstream of the GFCI.
Yes, the switch and outlet are in the same box (far right). I did change out that outlet, connected the black and white to "line" but there are no wires to connected to "load".
 
#12 ·
If you're comfortable with electricity:

Here's how I solved that problem, but I had all outlets with four wires on them except for the last one.

Let's say outlet #1 is the outlet closest to the source, and outlet #2 is next in line, then outlet #3 is last in line, but you don't know which is which.

You unplug everything from the outlets.

If you plug a heavy load into #1, let's say a toaster, and you measure the voltage drop from the short slot of #1 to the short slot of #2, you will get zero voltage drop because no current is flowing in the hot wire connecting #1 to #2.
Same zero volts for the hot wire from #2 to #3.
Use a plug pulled out slightly to make sure you're making contact with the outlet internal contacts.

If you get 120v the outlet wires are reversed and that needs to be fixed.

If you plug in a heavy load into #2 and you measure the voltage drop from the short slot of #1 to the short slot of #2,
you will get about 100 millivolts (assuming #14 AWG) due to the 10A flowing,
and zero volts from #2 to #3 because there is no current flow.

If you plug in a heavy load into #3 and you measure the voltage drop from the short slot of #1 to the short slot of #2,
you will get about 100 millivolts,
and you will also get about 100 millivolts from the short slot of #2 to the short slot of #3.

Keep track of your readings and you should be able to figure out which outlet is #1, the farthest upstream.

If this #1 outlet is not fed by four wires, I don't know how you'll put in a GFI that can switch off the downstream outlets.
 
#15 ·
I posted this in another thread on GFCI outlets:

You can ask for a "GFCI plug in tester" but at any rate you should be able to find this at any home center in the electrical department. I just "google-image" searched for "GFCI tester" to find that picture. I have one that works wonders for properly testing GFCI's. You will likely see two types of the same thing, and one will probably be a little cheaper. Usually the cheaper one does not have the ability to test the GFI's (does not have the button) so make sure you get the right one. Other than the button they both do exactly the same thing.

Here's a link to a product at Home Depot made by Gardner Bender: http://www.homedepot.com/webapp/wcs...log.beans.EndecaDataBean@d1eb2cd&ddkey=Search
Use this to test the proper functionality of the GFCI in the downstream outlets, the button should cause the GFCI to trip when pressed, and doubles as an outlet wiring check to make sure its wired properly. These are cheap, the link to Home Depot show it costing only $7.87 each. Very handy tool to have in your toolbox; they make a similar tester but it does not have the GFCI built-in tester on it though.
 
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