Wiring question (not tool related).

[Tony (Charleston WV)]

Moderator--sorry if this post should be in another forum.  I do most of my lurking here and am most comfortable with the folks who hang out here as well.  (Move if ye must.)

Folks:

I need some advice to get the wiring to the dishwasher I just installed figured out.   My apologies for the horrible drawing (obviously not to scale).  I was the art class joke in high school.  I've also attached pictures that might be useful.  

Oops--The drawing shows up in the post box--twice--but not in the preview box.  If it doesn't show when I post the thread, I'll try to add it when I can figure out what's going on.

Left to right in the drawing, are 1) dishwasher, junction box, disposal, and switches that control a light over the sink and the disposal.  Four 12/2 (with ground) enter the box as shown. Left goes to the DW, top goes to the disposal, the two on the right go to the light and disposal switches.  An outlet in the box with the switches is fed from a separate 12/2.  Each of the switches and outlet are wired separately--one 12/2 goes to each--black, white and ground.  Nothing ties together.

In the box all the blacks are together, whites together, grounds together and fastened to the grounding thing.  All connections are tight and not in contact with anything they shouldn't be touching.  (I noticed the ring and piece of bare ground in the box after I posted the picture and tossed them.)

Here's what I think happened.  When replacing the 12/2 from the old dishwasher (thought it would be prudent to do that), I tagged each strand separately, but the writing on 2 or 3 got so smudged that I couldn't read them.  I think that at least 2 if not 3 of the blacks were tied together with one of the whites.  If that's right, I don't want to guess which white goes with the blacks.

When I flip the breaker, it trips, sometimes after the disposal comes on for a second.  The disposal switch works backwards this way--off is up, on is down.

Some assistance would be appreciated.  Thanks.

Tony

[Admiral]

You are better off in home improvement, seriously, there are experts there.

[blackhat]

Seems the forum software is acting up again, I received your PM but when I try to reply it flags it as an unregistered recipient error.

None of your pics or drawing are showing up now either.

IIRC you had a 3 gang box with 2 switches and a receptacle, one switch going to a light fixture, one switch going to the disposal, and a feeder going to the dishwasher.  A separete breaker feeds the receptacle.  Did one breaker feed everything else?

[Tony (Charleston WV)]

I hope the pictures show up.  If not, I could send them via email.

One circuit serves the disposal and dishwasher.  There is a circuit labeled "dining room and kitchen lights" which I assume feeds the light switch in the 3 gang box.  There is a circuit for kitchen receptacles.  

What is confusing me is that there is only one 12/2  each to the light switch and the disposal switch. Is that possible?

I can't figure out the two feeds (12/2 + ground-one blue and one white) shown on the diagram going between the junction box and the light switches.  I assumed that was the set up because those two feeds go through the wall along the kitchen sink drain pipe (with trap) and the two feeds to the two switches are also blue and white.  

I'm not working today so I'll be around the house for the most part, with some trips to run errands.  I won't be far from the house or out too long, so I'll be able to see any PM or post you leave.

Would it be simpler to do this by phone, if you're inclined?

Thanks,

[blackhat]

Much better with the pics showing up now.  What's missing from this picture is a power supply to that junction box.  Kill the breaker to the disposal and kitchen receptacles and see if you have voltage to ground on either wire going to the light switch.  If so, the white cable coming into the junction box with the blue is actually a power supply feed. Otherwise we are missing some splices somewhere from the picture that's building.

[Tony (Charleston WV)]

Much better with the pics showing up now.  What's missing from this picture is a power supply to that junction box.  Kill the breaker to the disposal and kitchen receptacles and see if you have voltage to ground on either wire going to the light switch.  If so, the white cable coming into the junction box with the blue is actually a power supply feed. Otherwise we are missing some splices somewhere from the picture that's building.

Can you explain "voltage to ground " and tell me how to figure it out using my digital multimeter?  I've found the phrase online but the discussion is way above my familiarity with electrical terminology (which barely registers a blip).  

Thanks,

Tony

[blackhat]

In a nutshell, you are going to measure, using the meter, the AC voltage difference between a given point and an earth ground.  Earth ground is any conductor that goes back to, literally, the dirt outside.  All those bare wires and any metal they are connected to are a path to ground.  When measuring voltage we typically measure between a hot source to ground, neutral or another hot leg.  If you stick the probes in the long straight slots in a regular outlet you are measuring hot to neutral.  One probe in the round hole in the receptacle and you are measuring the slot to ground.  Please check your meter manual to ensure you have the dials, buttons and probe connections configured to measure AC voltage.  Insert one probe tip in each slot of a working receptacle and the display should read approx 120 volts AC.  Once you have proven the meter works, you can carefully check each screw on the light switch against a ground. One or both should read 120 volts, one if the switch is off, both if the switch is on.

[crokett™]

Does power come into this at the junction box or at the box where the receptacle and switches are? Is the dishwasher switched or is it always on? Since you have switches in this, I can tell you that you won't have all the whites together and all the blacks together. If you tell me where power is coming in, I can tell you how it most likely should be wired.

[Tony (Charleston WV)]

In a nutshell, you are going to measure, using the meter, the AC voltage difference between a given point and an earth ground.  Earth ground is any conductor that goes back to, literally, the dirt outside.  All those bare wires and any metal they are connected to are a path to ground.  When measuring voltage we typically measure between a hot source to ground, neutral or another hot leg.  If you stick the probes in the long straight slots in a regular outlet you are measuring hot to neutral.  One probe in the round hole in the receptacle and you are measuring the slot to ground.  Please check your meter manual to ensure you have the dials, buttons and probe connections configured to measure AC voltage.  Insert one probe tip in each slot of a working receptacle and the display should read approx 120 volts AC.  Once you have proven the meter works, you can carefully check each screw on the light switch against a ground. One or both should read 120 volts, one if the switch is off, both if the switch is o

Checking the screws on the light switch against a ground, there's roughly 120 volts AC to one of the screws when the switch is off, both when the switch is on.


To Crockett

There is 120 volts to both screws on the light switch when it's on (tested with the disposal-which has it's own circuit--and the circuit for the receptacles off).  I assume that means power comes into the box with the two switches and the receptacle. The disposal is fed by the 12/2 coming out of the top of the junction box directly to the disposal, and the DW is fed by the cable coming out of the left of that box.  I assume that means that the power is coming from the feed coming out of the switch/receptacle box.  That is the white cable.  The dishwasher is always on (power is available when DW is turned on).

Thanks,

[blackhat]

Checking the screws on the light switch against a ground, there's roughly 120 volts AC to one of the screws when the switch is off, both when the switch is on.


To Crockett

There is 120 volts to both screws on the light switch when it's on (tested with the disposal-which has it's own circuit--and the circuit for the receptacles off).  I assume that means power comes into the box with the two switches and the receptacle. The disposal is fed by the 12/2 coming out of the top of the junction box directly to the disposal, and the DW is fed by the cable coming out of the left of that box.  I assume that means that the power is coming from the feed coming out of the switch/receptacle box.  That is the white cable.  The dishwasher is always on (power is available when DW is turned on).

Thanks,

OK, remove the wire nuts and carefully separate all the wires.  Use the AC volts on your meter, check the black and white to each other, from the white cable coming in the right side of the junction box.  The disposal circuit breaker should give you 120 volts between those 2. This assumes that blue cable goes to the disposal switch. If the white cable has no voltage when the breaker is on, check the black and white wires from the blue cable.