"simple" electrical problem cant solve

[EvilBetty]

I am an electrical dunce. however, due to insufficient funds i've decided to do all the wiring in my renovation. Thought i was all set to go but then i had a short and can't seem to figure it out.

5 lights are run in sequence with a 3 way switch at either end. Power source comes into the light first. I followed this diagram. I wired everything up except the ground wires to do a test run. turned on the breaker and everything was good. all switches worked as they were supposed to.

flipped off the breaker, twisted all the grounds together and this trips the breaker. somehow a ground has become hot?. if i touch the ground from the power source to a ground from C3 or C4 it trips the breaker. what am i missing here?

If you have the answer, speak to me like a child because as mentioned, i am an electrical dunce.

 

[dirtyninety]

Good Luck. I share your electro-ignorance. I've done this before too....exactly what you are doing but I had someone help me....I was just tieing pigtails.

 

[TruClone]

Are you sure the ground pigtails are connected to the ground post on each switch? If so, I am not sure what is wrong. Is your ground from the power source also done correctly and pigtails to the ground of your light run?

 

[3GenClone]

Is the problem isolated to one of the fixtures? I would add the ground and test each fixture isolated from the rest. Possibly a bad fixture or wiring in a particular light?

 

[Rabbuk]

Is the problem isolated to one of the fixtures? I would add the ground and test each fixture isolated from the rest. Possibly a bad fixture or wiring in a particular light?

i was going to say bad fixture too.

 

[EvilBetty]

Are you sure the ground pigtails are connected to the ground post on each switch? If so, I am not sure what is wrong. Is your ground from the power source also done correctly and pigtails to the ground of your light run?

yeah, that part is seems fairly idiot proof. green goes to ground. bare wires attached to each other and to green screws/wires.

 

[EvilBetty]

i was going to say bad fixture too.

the fixtures are brand new, is getting a bad fixture a common occurrence?

 

[CyCloned]

One of the ground wires must be touching a white or red wire. I believe the black wire and the ground are actually the same in the circuit box

 

[GrindingAway]

One of the ground wires must be touching a white or red wire. I believe the black wire and the ground are actually the same in the circuit box

I think you have black and white mixed up here. White (typically anyway colors aren’t always reliable) is neutral. Neutral and ground are essentially the same in the breaker panel, but don’t treat them the same outside or it can cause issues.

Regarding the problem have you put all the fixtures back into their box/fully installed? Seems like as someone else said there is a hot or traveler touching a ground somewhere. Bad fixture somewhere is another possibility but I think less likely.

if it was me I’d start taking things out of the circuit one by one until the problem goes away. The last one that you remove before the problem corrects itself is the issue.

 

[NWICY]

the fixtures are brand new, is getting a bad fixture a common occurrence?

Certainly not unheard of.

 

[Acylum]

Is your breaker standard, AFCI, or GFCI?

 

[ImJustKCClone]

the fixtures are brand new, is getting a bad fixture a common occurrence?

We bought a vanity light bar with 6 lamps on it. Four days after installing it, one of the lamps shorted out. So yeah...not unheard of, even when it comes "pre-wired".

 

[Taz4President]

I think you have black and white mixed up here. White (typically anyway colors aren’t always reliable) is neutral. Neutral and ground are essentially the same in the breaker panel, but don’t treat them the same outside or it can cause issues.

Regarding the problem have you put all the fixtures back into their box/fully installed? Seems like as someone else said there is a hot or traveler touching a ground somewhere. Bad fixture somewhere is another possibility but I think less likely.

if it was me I’d start taking things out of the circuit one by one until the problem goes away. The last one that you remove before the problem corrects itself is the issue.

Likely this. When you’re stuffing everything back in the boxes it’s easy to push a ground against a hot terminal especially since the ground isn’t insulated. Push the ground wires into the boxes first so you can position them well up to the back of the box and then position the hot and neutrals as far way as possible. Make sure you don’t have exposed copper sticking out past the wire nuts because too much insulation was stripped. An extra insurance step is wrapping the hot and neutral wire nuts with tape. Wrap electrical tape around the made up switches to cover the terminals especially if you have metal gang boxes.

 

[DJSteve]

Do you have a digital multimeter? It would likely be easier (and safer) to look for the short using a meter measuring resistance--or continuity audio tone if it's a dead short--than turning breaker on and seeing whether it trips.

That diagram is difficult for me to follow without re-drawing it and really thinking through what's going on. Basically you need to figure out which wires are shorted electrically (presumably ground to hot, somehow) and then start taking the circuit apart in the middle. After splitting the circuit, use the meter to check resistance on wires again to determine which side of what you took apart has the short, then repeat as necessary to narrow down the exact location.

A few things to try / check:
Any change in behavior if bulbs are installed in fixtures or removed?
Are all electrical boxes plastic, or are any metal? Metal box could be shorting out conductors if insulation is nicked somewhere.
Are you positive bare copper ground wires are not touching exposed hot/neutral screws anywhere?
Any chance a nail or screw or something could have gone through the romex and be shorting ground to one of the other wires?
Is circuit breaker arc fault, GFCI, or regular?

 

[Pat]

Do you have a digital multimeter? It would likely be easier (and safer) to look for the short using a meter measuring resistance--or continuity audio tone if it's a dead short--than turning breaker on and seeing whether it trips.

That diagram is difficult for me to follow without re-drawing it and really thinking through what's going on. Basically you need to figure out which wires are shorted electrically (presumably ground to hot, somehow) and then start taking the circuit apart in the middle. After splitting the circuit, use the meter to check resistance on wires again to determine which side of what you took apart has the short, then repeat as necessary to narrow down the exact location.

A few things to try / check:
Any change in behavior if bulbs are installed in fixtures or removed?
Are all electrical boxes plastic, or are any metal? Metal box could be shorting out conductors if insulation is nicked somewhere.
Are you positive bare copper ground wires are not touching exposed hot/neutral screws anywhere?
Any chance a nail or screw or something could have gone through the romex and be shorting ground to one of the other wires?
Is circuit breaker arc fault, GFCI, or regular?

This is better, wiser advice than I could offer, but, as a barely-amateur, the $10 I spent on a multimeter has paid for itself many times over. Plus, I can figure out which batteries are almost end-of-life for the noisy, obnoxious kid’s toys.

 

[Cdiedrick]

I am an electrical dunce. however, due to insufficient funds i've decided to do all the wiring in my renovation. Thought i was all set to go but then i had a short and can't seem to figure it out.

5 lights are run in sequence with a 3 way switch at either end. Power source comes into the light first. View attachment 72881 I followed this diagram. I wired everything up except the ground wires to do a test run. turned on the breaker and everything was good. all switches worked as they were supposed to.

flipped off the breaker, twisted all the grounds together and this trips the breaker. somehow a ground has become hot?. if i touch the ground from the power source to a ground from C3 or C4 it trips the breaker. what am i missing here?

If you have the answer, speak to me like a child because as mentioned, i am an electrical dunce.

This is what electricians are for, or just let your house burn down‍

 

[EvilBetty]

Is your breaker standard, AFCI, or GFCI?

That breaker is standard

 

[BCClone]

At light one, you have a ground that leads to something or somethings else. You should also trace those. Best bet is do as a previous poster said and buy a meter, it will save you time and you might find different problems also.

 

[LowOverhead]

Just a safety note: a white wire usually called a neutral, it is a GROUNDED conductor. A green or bare wire is a GROUNDING wire. If a white wire is disconnected from ground it is a conductor and will shock you if you become it’s ground. White wires can shock and kill you (in certain circumstances).

Your drawing shows porcelain light fixtures. They usually have a white screw and a gold colored screw. The neutral white wire (grounded conductor) connects to the white screw. The black wire connects to the gold screw. The reason is the white wire then connects to the shell (thread portion) of lamp socket. This makes it safer if you screw a bulb into a turned on fixture.

In the same manner, if you are working with a fixture with a long stem and two black wires are sticking out to hook your black and white wires. Look closely at those two black wires, one will have a white stripe or white line or it may have tiny ridges. It is usually connected to the shell of the socket. This is for your safety. Will the fixture work if the wires are reversed, yes it’s likely it will.

So, this last safety note, never assume a white wire is “safe”. If you open up a junction box and start disconnecting white wires from each other, you may turn a grounded conductor into conductor (hot) wire. You could become the ground and get shocked. Don’t work on live, hot, circuits. Buy an inexpensive tester. Or better yet HIRE AN ELECTRICIAN.

 

[cyphoon]

I wired everything up except the ground wires to do a test run. turned on the breaker and everything was good. all switches worked as they were supposed to.

flipped off the breaker, twisted all the grounds together and this trips the breaker.

I think you have the hot and neutral wires connected properly because the lights worked fine when the grounds were not connected. Since grounding the system flips the breaker immediately (before turning on the lights), I think one of your hot pigtails is being grounded to the metal box it is in.

This is a dangerous situation. It means that one of your boxes is essentially wired to 120V. Electrocution hazard.

The safest course of action is to stop reading and call an electrician. If you are too stubborn to do that, then here is how I would debug if I was you as long as there is no metal conduit involved, and your boxes are all mounted to wood studs. If that isn't true, call an electrician.

1. Turn off the breaker and leave it off until step 4
   
2. Glance at each box and look for this type of fault. Look for loose wire nuts, and bare copper from under the nut touching the metal box. Hopefully you can spot it
   
3. If that doesn't work, find the first box that you ran wires to from the breaker panel. Do these steps at that box only!
   • separate the ground pigtail
   • find the conduit the comes directly from the breaker box
     
   • connect the bare ground wire from that conduit to the green screw on the metal box
   • leave all other grounds floating in air, not touching each other
4. Walk back to the breaker box and flip the breaker on
5. If the breaker trips, then you know that the short is in that first box. Focus your effort there
6. If the breaker doesn't trip after a few seconds, then turn it off and continue.
   
7. Go back to the first box and connect one downstream ground wire to the ground wire that you connected to the green screw. You should have the ground from the breaker panel connected to the green screw and one downstream circuit. The other ground wires should still be floating in air and not connected.
   
8. Repeat the breaker test. If it trips, then your shirt lies somewhere in the circuit that you just tied to the ground. If not, turn the breaker off and repeat.
9. Keep fanning out away from that first box until you find the short.
   
10. Only leave the breaker active for a few seconds at a time. Until you fix the problem, the breaker must be off before you walk away from the panel

That is how I was debug if I was you. But I am not you. I would debug by unwrapping all the pigtails, tell my wife to leave the house, turn the breaker on, and then measure which box is at potential using a multimeter set to AC volts. But this places you in the presence of an electrocution hazard, and you admitted to being a dunce, so I like avoiding that.

good luck
H