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Help! Wiring dishwasher in mutliple 120-Volt Duplex Receptacle Circuit

Help! Wiring dishwasher in mutliple 120-Volt Duplex Receptacle Circuit

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  #1  
Old 03-10-09, 10:01 AM
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Help! Wiring dishwasher in mutliple 120-Volt Duplex Receptacle Circuit

Hi everyone I am new to the board.

I have 3 outlets I installed that aren't playing well together.

All outlets test correctly for neutral, hot, and ground.

From the breaker box it's a 3 wire configuration (W,B,R) the red wire connects a series 1st in the series is the GFCI outlet then the fridge, and the black wire from the breaker box goes directly to a dishwasher. The white wire from the breaker box is connected to the bottom of the GFCI and the top of the GFCI has two white wires going to both the fridge and DW.

The GFCI, and fridge work together (red wire) in the series but the DW (black wire) is tripping the CGFI. However if i plug the DW to the GFCI/fridge series both the fridge and DW work. So there is no issue with too much power for the amperage. That said I don't want both of these appliances permanently attached to the same 15amp breaker.

Back to the 3 wires coming from the breaker box - white, black, and red. The red and black are each hot and each wire is controlled by a different breaker switch but on the same breaker plate...a split 15/15 switch. One switch controls the red wire the other the black wire. The white connected to the strip on the box with the other white wires.

Appliances: Both the fridge and dishwasher are 15amp 120v

Outlets: 1 CGFI, 1 standard (fridge), and 1 appliance (dishwasher)

Again the GFCI and standard outlets are in a series (via a black wire attached to the top of the CGFI to the fridge). The appliance outlet (dishwasher) is connected directly to the black wire from the breaker box. I tried several configurations of the white wires with no success, i explain the white wire configuration below.

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How the 3-wires from the breaker box are wired into my outlets
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Red Wire - installed to the bottom of the GFCI outlet and the fridge runs on a series off of the GFCI using a black wire connected to the top of the GFCI (to appliance)

Black Wire - installed directly to an appliance outlet from breaker box

Now for the white wires I tried 2 configurations with the white wires - both failed:
1st config.
White Wire - installed to bottom of GFCI (from breaker) and on top are 2 separate wire that come out of the top of the GFCI (to appliance) and runs on a series, 1 to the fridge the other to the dishwasher.

Result: Fridge and CGFI work fine but when I plug in the dishwasher the the GFCI blows (remember the black is direct from the breaker box to the DW but the white wire to the DW is connected to the top of the GFCI).

2nd config. ( wired like i think it should judging by the electical book)
White Wire (from box) - joined together with other two wires going to Fridge and DW and a pigtail runs to the the top of the GFCI (from breaker). In this configration there is no white wire connected the bottom of the GFCI outlet.

Result: Fuse blows on GFCI as soon as I power on from the breaker..i.e. neither GFCI,fridge or DW work

I have tried reversing the red and black - running the red to the DW instead and the black to the fridge. This simply reverses which appliance trips the GFCI.

What puzzles me is that each outlet passes the test for correct hot, neutral, and ground but when I plug in the dishwasher it blows the breaker. I would think then that its a power issue from the breaker box of the GFCI cant handle the amps but both the fridge and dishwasher worked together when I plugged the dw into the GFCI (which is connected to the fridge via the series, powered by the red wire). I could hear the compressor running so the fridge was on and the dishwasher motor was turning.



Please help,
thanks,
james
 
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  #2  
Old 03-10-09, 10:45 AM
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What you have is a MWBC or a multi-wire branch circuit.

I would read a book on electrical wiring so you fully understand how these circuits operate.

These circuits are dangerous! Be sure to turn off both breakers to this circuit before working on one of the circuits. Or better yet, turn off power to the whole house, then you will be sure.
 
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Old 03-10-09, 10:49 AM
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Post deleted.

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Last edited by ray2047; 03-10-09 at 11:16 AM.
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Old 03-10-09, 10:59 AM
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Originally Posted by Bill190 View Post
What you have is a MWBC or a multi-wire branch circuit.

I would read a book on electrical wiring so you fully understand how these circuits operate.

These circuits are dangerous! Be sure to turn off both breakers to this circuit before working on one of the circuits. Or better yet, turn off power to the whole house, then you will be sure.
Bill, I don't think he has a multi- wire curcuit. He write in his thread that he has a 15/15 breaker which to me it's a tandom breaker which now it's on only 1 phase of his panel box. If I read this correct there could be a fire hazard now on the neutral. It will carry the complete load of both curcuits so it could be a potenial of 30 amps on the neutral. Maybe I'm not reading this correct. I'll read the thread later.

JimBeer 4U2
 
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Old 03-10-09, 11:13 AM
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Sorry about that Ray. In my example the line side of my GFCI is the "bottom" (from the breaker box) and the top is the load (to other recepticle..in my case going to the fridge (standard outlet).

Just so I hear you correctly what I should do is daisy chain on the line side of the CGFI to next in the recepticle in the series, for hot and neutral. That is, pigtail the red wire (hot) from the breaker line to the line side of the CGFI and join this with the hot (black) going to the next receptacle on the curcuit. Same config as above for the neutral.

Is this correct?
 
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Old 03-10-09, 11:17 AM
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Sounds to me that he is using a 15/15 on a three wire circuit, which means he is sharing a single neutral connection on the same phase, which is a fire hazard as rukkus11 mentioned. The reason the dishwasher is tripping the GFCI is because it is "seeing" an imbalance in the amount of current flowing through the neutral and hot since the hot wire is not connected to the GFCI whereas the neutral is. Regardless, he should not be connecting a 3-wire circuit to a single phase.
 
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Old 03-10-09, 11:22 AM
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I may be mistaken regarding the GFCI, but something doesn't see write about your setup. The refrigerator shouldn't be on a GFCI plug, and should be on a 12 AWG/20 amp line, whereas your dishwasher should be on a 14 AWG/15 amp line. The larger gauge on the D/W is fine as long as you are using a 15A breaker. However, a 14AWG/15 amp line to the fridge is not ok. I will try to look at your question a little closer and provide further as necessary.
 
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Old 03-10-09, 11:26 AM
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Well I think you are both correct. I pulled the breaker out this morning from the box and saw that it's connected to 1 plate, but there are two 15 amp red switches on top. There is a red wire attached to 1 breaker and a black wire attached to the other. I beleive you are calling this a tandom 15/15 breaker on one phase on my panel is correct. I was thinking I should have a second white wire to pair with the black but I am not sure.

If this is true then I guess you are correct in surmising the white wire on my GFCI is taking 30 amps.
 
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Old 03-10-09, 11:33 AM
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Originally Posted by jnevinsiv View Post
From the breaker box it's a 3 wire configuration (W,B,R) the red wire connects a series 1st in the series is the GFCI outlet then the fridge, and the black wire from the breaker box goes directly to a dishwasher. The white wire from the breaker box is connected to the bottom of the GFCI and the top of the GFCI has two white wires going to both the fridge and DW.
Sounds like a MWBC to me.

First thing - There has to 240 volts between the black and red wires. That way the neutral only carries the unbalanced current between them. You'll need a 120/240 2 pole circuit breaker that will disconnect both hot wires simultaneously (one handle or a handle tie).


Connect the wires to the GFCI receptacle as follows:

Splice a red wire to the red power wire (pigtail) and the power wire to the fridge receptacle. Splice a white wire to the MWBC neutral and the neutral for the fridge receptacle. Connect the pigtailed power wire and neutral wire to the line side of the GFCI receptacle. Brass screw is hot. Silver screw is neutral.

Do not have any other wires connected to the load side of the GFCI receptacle.


Question: Where is the GFCi receptacle located? It may have to be a 20 amp circuit.

It would be a good idea if you grouped the MWBC black, red, white and bare wires together in the main panel. Use a plastic wire tie to accomplish that.
 
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Old 03-10-09, 11:35 AM
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Mossman, Yes the fridge is on a GFCI on a 15amp breaker. I installed the GFCI but the 15 amp breaker was there when I moved into the Brownstone.

What I hear you saying is I should forget the multi-wire configuration - install separate 20amp breaker and a separate 15 amp breaker and throw the tandom 15/15 into the East River. I believe 12 gauge wire being used all around. If I do this I would need to run a new BX 12 gauge cable from the 20amp breaker to the fridge.

Is this correct?
 
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Old 03-10-09, 11:38 AM
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Originally Posted by mossman View Post
14AWG/15 amp line to the fridge is not ok. I will try to look at your question a little closer and provide further as necessary.
NEC states the fridge can be on a 15 amp or larger circuit.

I want to know where the GFCI receptacle is located? Kitchen? Dining Room?
 
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Old 03-10-09, 11:45 AM
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Thinman, I followed what you said concerning wiring the GFCI with the pigtails at the line side. Both the dishwasher and fridge are using the 15/15 tandom breaker. If one has to be 20amp what type of circuit breaker would you recommend?

Basically what I've done is installed a GFCI recepticle behind the fridge an appliance recepticle to the dishwasher. The dishwasher was originally wired to the junction box only, again I attached the outlet.
 
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Old 03-10-09, 11:48 AM
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Thinman, To clarify I have a GFCI behind the fridge, a GFCI on the backsplash between the wall and base cabinets and an appliance outlet along the baseboard behind the dishwasher. I also installed a GFCI behind my gas range but this seems to be working correctly.
 
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Old 03-10-09, 11:57 AM
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Thinman, I saw your post - 15amps are okay for the fridge and dishwasher.

To confirm I a 120/240 volt 2-pole curcuit breaker should be okay?
 
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Old 03-10-09, 12:00 PM
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Thinman, sorry about that. All the appliances and outlets are in my very small kitchen.
 
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Old 03-10-09, 12:46 PM
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I think its an excellent idea to drop the 3-wire MWBC and use two separate regular romex cables for the two separate circuits.

Keep it simple!

I prefer 20 amp circuits and 12 ga. wire to the kitchen stuff.

And if you are running new wire and can easily do this, might want to run a 3rd for an additional or existing counter top outlet(s) on its own 20 amp circuit.

There are lots of "power hogs" in a kitchen, so the more circuits, the merrier!
 
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Old 03-10-09, 01:46 PM
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Sorry to be the bearer of bad news.

You need to install 2-20 amp small appliance branch circuits using 12/2 w/ground romex and 2 individual 20 amp circuit breakers.

The only appliance that can be connected to the small appliance branch circuit is the refrigerator.

Is there enough space in the main panel for the new breakers?
 
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Old 03-10-09, 01:53 PM
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Just so you know the fridge or the dishwasher doesn't need a GFCI. On the dishwasher I will hardwire that in. I'm not sure if you're starting to get confused. Let us know what you're thinking.

Jim Beer 4U2
 
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Old 03-10-09, 01:58 PM
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You said "Brownstone" and "East River". Is this a rental or multi-family residence and is this in NYC, NY? If it's multifamily or rental you can't do the wiring. If it's NYC you may not be able to use NM (Romex). You may need to use armored cable.
 
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Old 03-10-09, 02:22 PM
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Thanks guys. Yes it's a little complicated for me but I think I can get it right.

Thinman
Regarding your last reply "You need to install 2-20 amp small appliance branch circuits using 12/2 w/ground romex and 2 individual 20 amp circuit breakers"

Are these 2 20 amp small appliance branch circuits powering my D/W outlet and the GFCI outlet between my base and wall cabinets? Do I have to run these as MWBC or can I run these separate?

Can I use BX cable instead?, it's all BX cable in my house currently.


Can I reuse the 14 gauge BX cable going to the fridge on a 15 amp breaker but replace the tandom breaker with a single pole breaker and wire it straight to the fridge?
 
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Old 03-10-09, 02:26 PM
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Oh boy. Yes this is a Brownstone CO-OP in brooklyn. There are 12 units 100% owner occupied.

You are saying I need to hire someone to do the work?
 
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Old 03-10-09, 02:38 PM
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Find out if you are allowed to do the wiring and let us know.
 
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Old 03-10-09, 02:49 PM
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Will do. Thanks guys for your help today.
 
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Old 03-11-09, 07:40 AM
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Thinman I wired the GFCI like you said for a MWBC using the line side only (no wires on the load terminal for the 1st receptacle in the series). All three appliances are now playing well together. Thanks!

I decided I will hire a contractor to do whatever needs to be done in the kitchen to get it to code but for now the GFCI outlet between my wall and base cabinets seems to be wired correctly.

thanks a lot guys,

jim Beer 4U2
 
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Old 03-11-09, 10:06 AM
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Originally Posted by jnevinsiv View Post
Thinman I wired the GFCI like you said for a MWBC using the line side only (no wires on the load terminal for the 1st receptacle in the series). All three appliances are now playing well together.
BRAVO!!

Originally Posted by jnevinsiv View Post
I decided I will hire a contractor to do whatever needs to be done in the kitchen to get it to code but for now the GFCI outlet between my wall and base cabinets seems to be wired correctly.
Good decision!!!
 
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