Go Back  DoItYourself.com Community Forums > Electrical, AC & DC. Electronic Equipment and Computers > Electrical - AC & DC
Reload this Page >

Can someone help me understand my kitchen GFCI, 2 switch box wiring?

Can someone help me understand my kitchen GFCI, 2 switch box wiring?

Reply

  #1  
Old 01-29-17, 12:57 AM
B
Member
Thread Starter
Join Date: Jul 2016
Location: United States
Posts: 892
Received 0 Votes on 0 Posts
Can someone help me understand my kitchen GFCI, 2 switch box wiring?

Hi.

I've wired everything up and installed the new GFCI so there's no problems, however I'm a curious person and trying to understand electricity and circuits somewhat. I've learned a lot thanks to you guys so far!

So, as some of you may know, I've got a switchplate on the right side of my kitchen counter that has 2 switches and then a GFCI. One switch controls an overhead sink light and the other controls the garbage disposal.

There are 5 cables coming into the box. I think two are 12/2 and three are 14/2 from what I can now remember.

The POWER IN seems to go to my GFCI first on the LINE. From the GFCI the LOAD goes out to the garbage disposal switch with a white wire.

1. Is there are reason the LOAD goes out to the switch on a white wire? Should it have a tape on it?

the otherside of the garbage disposal switch has a black wire going back to the a cable and I believe the white wire from that samw cable goes to a pigtailing of all the white (neutral?) wires in the box, save for the one used for the LOAD from GFCI to disposal switch as far as I can tell.

From what I can make out I assume that the POWER for the light above the sink must come in also to this box. The light (from what I can remember) only has a 14/2 wire up at the light over the sink.

So I would assume that one of the cables coming into this box is a 14/2 and the black is going to the light switch? Then the white from that cable is ties into the NEUTRAL (white) pigtail also in this box?

I think I MAY understand it now, but I'm not sure. I'm going to try and explain what I think is happening. Maybe someone can be so kind as to verify this for me.

FIRST* I'm assuming that the NEUTRAL whites CANNOT be pigtailed together in the box if they're 12/2 and 14/2 right?

So I have three 14/2 cables and two 12/2 cables in this box. One light switch, one GFCI and one disposal switch.

1. The disposal and GFCI are on a 20 amp circuit, so that explains the two 12/2 cables in the box?

A. ONE of the 12/2 cables goes to the LINE of the GFCI
B. the LOAD goes out on a white wire to the disposal switch (which I think should be taped black).
C. The black wire from the switch goes OUT on the other 12/2 cable to the disposal unit and the white wire comes back to the neutral side of the LOAD on the GFCI from that same cable.

That takes care of the two 12/2 cables.

Now I'm a little stumped as to why there's three 14/2 cables coming into this box.

A. I assume one is a POWER IN for the light/switch circuit and one is back to the light.

B. There's another outlet behind my stove. Do you think the 3rd 14/2 must feed that one?
 
  #2  
Old 01-29-17, 04:27 AM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,965
Received 6 Votes on 6 Posts
Is it broke?.........................................
 
  #3  
Old 01-29-17, 05:54 PM
C
Join Date: Dec 2016
Location: United States
Posts: 29
Received 0 Votes on 0 Posts
The Line side is receiving the power. The load side is passing power to the next area and that item(s) will be protected by the GFCI. They will lose power if the GFCI is tripped.
I'm kinda confused by your descriptions but can tell you how my outlet for the disposal is hooked up: Black wire comes out of load gfci gold side and goes to gold screw on switch to turn disposal on/off. White line comes out silver side of gfci and is capped to white line from disposal outlet. a black line comes out of the silver screw of switch and goes to black line of disposal outlet.
 
  #4  
Old 01-29-17, 06:16 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 15,218
Received 103 Votes on 89 Posts
Neutrals from different circuits should not be spliced together.
 
  #5  
Old 01-29-17, 07:22 PM
C
Join Date: Dec 2016
Location: United States
Posts: 29
Received 0 Votes on 0 Posts
?? They are not different circuits. The pigtail merely lets me not have to stretch the white line to the outlet. Every diagram I've seen shows no neutral on the switch. The only thing different about mine, is that there are not two neutrals running to the outlet nor two hot lines. There is no room to add a dishwasher so both receptacles on the outlet go on and off with the switch.
 
  #6  
Old 01-29-17, 07:30 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,583
Received 13 Votes on 11 Posts
The only thing different about mine, is that there are not two neutrals running to the outlet nor two hot lines.
Not unusual in an end of the line receptacle. When you see two cables the second cable supplies another receptacle or other load.
There is no room to add a dishwasher so both receptacles on the outlet go on and off with the switch.
With the use of a 3-conductor cable instead of a 2-conductor cable you can switch only one.
 
  #7  
Old 01-29-17, 07:40 PM
Handyone's Avatar
Member
Join Date: Aug 2000
Location: U.S.
Posts: 5,450
Received 0 Votes on 0 Posts
B. There's another outlet behind my stove. Do you think the 3rd 14/2 must feed that one?
The 3rd cable might feed the range outlet or the vent hood, maybe both. The vent hood is allowed on a lighting circuit. Hopefully it's not feeding a dishwasher.

The important thing is you realize there are two circuits in that box.
This is common in kitchens, a switch for the sink light (15A circuit) and a switch for the disposal (20A circuit).
Turn off both breakers and as boss said, keep neutrals separate.
 
  #8  
Old 02-03-17, 08:25 PM
B
Member
Thread Starter
Join Date: Jul 2016
Location: United States
Posts: 892
Received 0 Votes on 0 Posts
Thanks everyone. I haven't had time or remembered this post since I've been updating other outlets all week.

NOTE: I have NOT altered the circuit(s) in this box at all, SAVE for taking the 2 blacks going into the old outlet (one in back and one in screw) and pigtailing them. My first PIGTAIL by the way!! Am I an electrician now? LOL

So it does look to me like all the white wires in the box are PIGTAILED together, but I may have been wrong. This switch/outlet was a ROYAL PAIN to get in also since there's the fat GFCI and the 12 gauge wires to bend, etc, but I finally got it all back together and everything aligned. I kind of dread taking it all back apart, but I want to make sure I twisted the pigtail wires together correctly (I believe 95% that I did, but just want to make sure for peace of mind!). At the time I used a needle nose plier to twist the wires being ignorant to the fact that you use linesman pliers.

While I was in there I did make note of every wire and where it went, but I don't have those notes on me at this moment.

So I guess what I do know is that:

1. The POWER comes into the GFI (up until now though it was a regular outlet, since house was built in 1971) on the LINE and goes out LOAD to the DISPOSAL switch.

2. THEN it looks to me as if all the white wires in the box are PIGTAILED! YIKES I guess it's always been like this since 1971 and nothing has happened! What should I do with these wires?

3. A WHITE wire although does go from LOAD on GFI to the disposal switch. Should I change this out to a black wire? Or just mark it with some black tape?

Is there a way to find out where every one of those 5 cables coming into the box are going? I guess it would only be maybe 3 or 4 because ONE cable brings in the power to the LINE on the GFI and is a 12/2.

I'm curious though as to why the white neutrals shouldn't be PIGTAILED. Do some electricians do this?

I think a good way for me to understand what's going on in here is to make some type of diagram of the circuit(s) for myself. I could draw it out and take a picture once I get it confirmed. I'm going to have to go back in (YIKES!) and really see where all those wires go once and for all! It's more of a curiosity thing for me, but now I'm worried about all the whites being tied together!

Funny thing is everything works right .....? Hmmmm ......
 
  #9  
Old 02-03-17, 09:16 PM
Handyone's Avatar
Member
Join Date: Aug 2000
Location: U.S.
Posts: 5,450
Received 0 Votes on 0 Posts
I have NOT altered the circuit(s) in this box at all, SAVE for taking the 2 blacks going into the old outlet (one in back and one in screw) and pigtailing them.
You HAVE altered the circuit if you are installing a new GFCI where one was not present before.

The 2 blacks that you pigtailed most likely do not belong attached to the same GFCI terminal.
One should be line and the other load.
 
  #10  
Old 02-04-17, 01:42 AM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 21,113
Received 3 Votes on 3 Posts
Have you purchased your copy of Wiring Simplified yet? And maybe Wiring 1-2-3 at HD? The first is better, but the second has good pics and diagrams.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: