I found this dial knob next to my breaker box (it is not connected to the breaker at all) it has a ground cable attached to it and the thin red and white cable (become a single black cable). Does anyone know what this is? My house was built in 1974 in the dc area.

An interesting unofficial addition - in the absence of further details, it looks as though it is a potentiometer though for what purpose is a mystery. Tracing the origin or destination of a couple of the wires would provide a clue.

A potentiometer can be used for a variety of low current purposes from providing a variable voltage; a volume control for an amplifier or loudspeaker is the most common application...

Turn off power between each action listed below.

Is dial rotating and keeping time on timer?
This will tell you if 120V is arriving and working at timer.
Cut ground wire and check circuit again.
This can narrow down ground fault problem.
Disconnect wires from timer and connect wires direct to outdoor lights.
This will tell you if timer is suspect.

List all things on same circuit breaker, and test each to find which are working.
Each electrical box is connected to next box and to next box back to circuit breaker.
Open each box and check for loose wires, signs of burning.
This will narrow down location of problem.

When working in main breaker box, the wires on main breaker have power at all times, even when main breaker is turned off. This is true unless meter is pulled. Always stand on dry boards and never lean into or touch anything else when working in main box. Do not hold screwdriver between teeth.
Tape tester leads to wood sticks to keep hands away from voltage.
Test voltage at circuit breaker. Make sure neutral and ground are attached tight on busbar. Make sure black wire is attached tight to breaker. Move black wire to another same-size circuit breaker. Disconnect ground wire and test circuit again to check if ground fault is causing problem.

Resources and illustrations.
http://waterheatertimer.org/See-inside-main-breaker-box.html
http://waterheatertimer.org/How-to-replace-circuit-breaker.html
http://waterheatertimer.org/B220C.html

T51211BC is 120Volt timer that can be wired many different ways because there are two internal relays, and each relay has NO and NC terminals. One relay is controlled by timer dial trippers, and other relay controlled by dawn-dusk photo eye

Timer wiring cannot be fully explained with words.
Below is basic hook-up for your 120Volt wiring application, and then you can use a tester and experiment with the knob settings, and tripper settings.
http://www.intermatic.com/products/ec%204%20layer/mechanical%20time%20switches/24%20hour%207%20day/t50000%20series%207-day%20time%20switch.aspx

1) You have 4 cables:
one cable from circuit breaker box;
one cable going to photo control;
one cable going to outdoor Load (lite);
one cable going to indoor Load (lite).

2) Cable from circuit breaker has 2 wires:
Black Hot wire connects to terminal 1
White Neutral connects to terminal 2
This will power the clock motor and timer relays.

3) Photocell has 3 wires:
Black connects to terminal 1
White to terminal 2
Red to terminal 3.
Photocell turns relay on-off for Circuit B
Do not mix different size wires under same screw terminal, or smaller wire will come loose over time. Also do not mix stranded wire and solid copper under same screw terminal for same reason.

4) Terminals 4 thru 12 are 'dry'.
Dry terminals receive no power when power is applied to terminals 1 and 2.
To put power on dry terminals, so that Load will have power, attach Black hot wire from breaker to terminals 9 and 12.
So add a jumper wire from terminal 1 to terminal 9 and another jumper wire from terminal 9 to terminal 12.
120Volt power is now connected to terminals 1, 9 and 12

5) Circuit B is dawn to dusk for outdoor Load.
Outdoor load cable has Black and White wire.
Connect outdoor Black wire to either terminal 10 or 11.
To test which is correct for your application, set switch to Auto, and then test across terminals 12 and 11, and across terminal 12 and 10. Repeat test after dark. Rotate knob B to each position and repeat test.
Connect outdoor White wire to terminal 2, and this will complete the circuit.

6) Circuit A is Dusk ON and timer OFF
Indoor cable has Black and White wire.
Connect indoor Black wire to either terminal 7 or 8.
To test which is correct for application, set switch to Auto, and then test across terminals 9 and 8, and across terminal 9 and 7. Repeat test after dark. Rotate knob B and repeat test.
Connect outdoor White wire to terminal 2, and this will complete the circuit.

First thing to consider is size of Load.
Leviton countdown-timer Load rating is 1800 Watt, 120Volt.
Look inside Jacuzzi at rating plate on motor.
Rating plate on motor should give Volts, Watts and Amps.
Formula Volts x Amps = Watts.
Sometimes motor shows VA which is Watts
Is Jacuzzi on 240Volt breaker or 120V breaker?
Leviton countdown timer is not for 240V load.

A) If 120Volt electric Load checks out, here's how to wire timer if 1 cable enter box.
Timer-black-wire connects to jacuzzi-black
Timer-white-wire connects to ground.
Timer-green connects to ground.
Timer-red connects to jacuzzi-blue.

B) Here's how to wire timer if 2 cables enter box.
120Volt cable coming from breaker box has black, white and bare copper wire.
Timer-black-wire connects to black-wire-from-breaker
Timer-white-wire connects to white-wire-from-breaker-box.
Timer-green and jacuzzi-ground connect to ground

Timer-red-wire connects to jacuzzi-black-wire.

Jacuzzi-blue-wire connects to white.
I am puzzled why this wire is blue if circuit is 120Volt.

http://www.intermatic.com/~/media/files/intermatic/products/instructions/timers/e1010%20-%20english.ashx
Half of the online manual is upside down.

According to the manual, the clock motor that operates the timer requires a separate Neutral wire.
The clock motor is a separate circuit, just like your alarm clock.

The wiring is:
Black-hot-from-breaker connects to timer-black wire
Wire-to-Load connects to timer-red wire

Timer-white wire connects to Neutral.
The Neutrals are white wires twisted together and covered with a wire nut.
Not every box has Neutrals ... in that case, connect timer-white wire to bare copper wire.
Bare copper wires connect back to the Neutral busbar in breaker box.
Attaching your white wire to ground is not code, but it will work.

How to test your wires:
Separate wires
Turn on power
Test each wire to bare ground
Tester lights up on Hot wire from breaker
Now test Hot from breaker to each of the other wires, except ground.
Tester lights up on Neutral

If I understand correctly, you are replacing a single switch that has two wires.
You want to install a switch/plug-gfci similar to one shown below.

You are working on wires inside a box:
To wire this kind of device you need at least 2 cables entering the box.
Each cable has a black-white-ground wire.
Cable 1) One cable comes from breaker box. This is the Hot cable
Hot cable has black-hot-from-breaker & white-neutral-from-breaker

Cable 2) One cable goes to the Load (light, fan motor). This wire is controlled by the switch. This is the Load cable
Load cable has black-to-load & white-to-load.



Leviton combo GFCI and Switch
There are 2 screws on either side of switch
There are 2 screws to either side of plug
There are two wires on back of device

2 screws on either side of switch: there is a brass-colored screw and silver-colored screw.
Black-hot-from-breaker connects to brass colored screw on side of switch
White-neutral-from-breaker connects to silver colored screw on side of switch

2 black wires on back of device
Black-to-load connects to black wire on same side of switch as brass-colored screws
White-to-load connects to black wire on same side of switch as silver-colored screws

2 screws on either side of plug
These screws are used when your box is a 'junction' box that feeds wires forward to another box ... for example you have 4 receptacles in a room, the cable enters first box and then goes to the next box and to the next box. Suppose your switch was one of the boxes. Wire arrives from a previous box (this is the Hot cable, every box has 1 Hot cable). Your switch box sends one cable to the Load (light, fan etc), but it also sends another cable to the next box which has a receptacle or another switch.
If your box has a third cable that feeds forward to other boxes, then the screws on either side of plug are used. The black-to-next-box goes to brass screw. The white-to-next-box connects to silver screw.
And all further boxes and devices are protected by the GFCI device.

If you need more information, please answer back and I will help.

No breakers are tripped and a circuit is dead.

There is a loose wire.

Let me explain how it works. Each 120V breaker has a black wire that leaves breaker box. The black wire is accompanied by a white neutral wire and a bare ground wire. These wires are sheathed in plastic, and altogether they make up a romex cable.

The cable leaves the circuit breaker box and travels to the first junction box. The junction box is a ceiling box that holds light or fan -or- a wall box containing switch or plug. As a general rule, the romex leaves the breaker box and travels all the way to a junction box located right in the area where lights and plugs are located. The romex does not stop at a junction boxes located in other room.

Inside the junction box, the romex splits and goes to the next junction box, and then to the next box, and the next.

So the plugs in one room are all connected together by a single romex cable that started back at the breaker box. And a single romex wire from the breaker box arrived at one of the junction boxes located in immediate vicinity of dead receptacle.

Here's what happened. A wire came loose somewhere between the breaker and the dead receptacles.

The loose wire is probably in a receptacle.

Here's what to do.
1) Breaker first: You can isolate the suspect breaker by identifying all other breakers. Then tighten screw on suspect breaker. Look for white wire and ground wire associated with the romex cable that connects to breaker >> tighten those screws on neutral busbar. Look for burning around suspect breaker. Is there a burning smell indicating breaker is bad?

2) Receptacles Next. Use ordinary tester. Test each receptacle. Receptacle has two rectangular prong holes and one round hole located below other two. The round hole is the ground. Breaker is turned on. Test each rectangular hole to ground. You have to test both prongs to ground.

The loose wire is right there in the vicinity of dead receptacles.

Test one receptacle and then move to next receptacle. At some point the tester will light up. Now click suspect circuit breaker to see if that receptacle is on breaker. Test receptacle with breaker off and breaker on. If that receptacle is on the suspect breaker, then a loose wire is inside that receptacle box >> or inside the next box. Many times, the wires are pushed into 'quick-connects' located on back of receptacle ... wires get loose ... you need a small screwdrive to release quick-connect, and then wrap wire around screw -or- replace receptacle

If none of receptacles show electricity, then loose wire is inside a switch box, or it is inside a ceiling box located in same general area. Check your switches first. Look for quick-connects, or signs of burning. Look for loose wire nut. Plug light into dead receptacle. Pull switch out with wires attaches. Power is on. Move switch around to see if dead receptacles shows electricity. Move to next switch. The loose wire is there somewhere.

Finally the ceiling box. Take down light and see if there is a loose wire inside. Look for signs of heat or burning.

What kind of Woods timer do you have?

Is the dial turning? The dial is the clock. And the clock needs electricity to work, just like alarm clock. If dial is not turning, the wiring is not right.

Does the manual override turn on the lights? Maybe the slider switch set to OFF? Set slider to "Timer" for timer functions to work.

Wall timer:
If you have 59017 wall timer, it has dark PM white AM. You rotate dial until correct time lines up with little triangle located on right side of center knob.


There are 48 plastic pins on dial ... when pins are moved out, the lights are off. For timer functions, set slide switch to 'Timer'
Correct wiring is needed for timer to work:
Timer black attaches to Hot wire from breaker box
Timer red attaches to wire going to Load (lights)
Timer white must attach to white Neutral (or if your box has no neutral, connect white to bare ground)
Timer green connects to bare ground

If wiring seems right but dial on front of timer is still not rotating, then reverse Timer red and Timer black and see if that sorts out problem.

If this is wrong Woods timer, please re-post question.

Alan

Generally, 3 wires indicate a "3way" switch where you have 2 switches at opposite entrances to a room. Both the Red and Black Can be hot, depending on the other switches position. But, a red wire would normally only be found at the switch box not the light.

What I'd suggest, is that you get a multimeter, and use it to determine the hot wire and the ground/neutral. Once you know which wire is hot, connect the hot to the black lead, and ground/neutral to the white lead of the light. That is the only SAFE manner I can see to resolve this.

Correct, assuming red and black are connected to the breakers in the breaker panel, and white is connected to the neutral/ground buss bar in the breaker panel.