Several weeks ago the 20A, standard breaker to my garage started tripping for no apparent reason. I reset it and it trips again. Sometimes within seconds, sometimes over an hour after the fact.

The box and breaker were newer (about 2 years ago) and no new work has been done to the garage or breaker panel anywhere close to when this started. Even though it is NOT a GFCI breaker, my brother recommended double checking grounds. I replaced the outlet the garage door opener (GDO) plugs into and grounded it properly. I rewired (grounding) the outdoor motion lights, and unplugged everything plugged into the other 4 outlets in the garage itself. That seemed to work for a while, but it tripped again as usual.

Thinking I may have a bad breaker I replaced it, but the same problem exists. As I said, no new work has been done so I cannot figure out to isolate the problem. I have a good volt meter, but no idea how I could use that to check for problems.

Just so everyone knows, it is a very old house. Isolating individual lines is very difficult though I am fairly confident that I have found the line the goes from the breaker panel out to the garage and found where it comes into the garage.

Manually opening and closing the garage door is getting really old. Can anyone help?

 

Is the garage detached? If so what type of cable runs to the garage.Misinformation there. A GFCI does not need a ground. Was the old breaker a GFCI. If not then the receptacles in the garage must be protected by another method such as the first receptacle being a GFCI and the rest daisy chained from the load side. Lights do not need GFCI protection.

 

Welcome to the forums! You only have one cable from the breaker to the garage, right? Does it travel underground? Is the garage attached to the house? Where it enters the garage, does it go directly to a receptacle? Can you identify that receptacle? If so, turn the breaker off, pull that receptacle and disconnect the incoming wires to it and cap them off. Then check to see if the breaker trips. If so, it is where it travels from the house breaker panel to the first receptacle.

 

Yes, the garage is detached. I'm not experience enough to tell you what kind of cable it is that's already running to it. It goes out the basement wall and under the driveway to get there.

As far as the GFCI breaker thing, I'm not sure if they are or not, but I don't think so. When I took the breaker to the hardware store they gave me an identical breaker. None of that should be the cause of it starting the tripping problem all of the sudden though. They have been out there working just fine even after the breaker box was installed over two years ago.

 

I will have to check the cable where it comes into the garage tomorrow when I have light to see. The breaker stays off, so no worries there. If it does not go straight to a receptacle and daisy chain is there another way to test?

 

The cable should be marked UF and have a gray jacket. If it has a white, or yellow, or black jacket and is marked NM or has a cloth jacket then the cable may be your problem.

 

Older UF can have a white jacket. I just worked on some today.

 

Just chiming in. I like Chandler's idea of seeing if breaker trips after cable is disconnected at point of entry to garage.

 

chandler's idea is the best way to proceed.

However, because the OP is inexperienced with electrical wiring, etc. please is needed to remember him that if for any reason after the Test the Breaker remains ON, REMEMBER TO TURN IT OFF AGAIN BEFORE TRYING TO REWIRE THE OUTLET OR WORKING WITH THE WIRES IN THE GARAGE!!!

 

I'm neurotic about making sure there is no current flowing before doing anything electrical. I have a non-contact voltage tester I use before I ever work on anything electrical.

The wire has a gray jacket but I do not see any markings. I will look again.

 

Your probably good if the jacket is gray. Do the test outlined above and we will go from there.

 

The line out to the garage is underground, as I mentioned. It is a gray jacket, metallic-sheathed cable, type NM, 600V, E 10816. I do not know if you need to know all of that but that's what it is.

The line runs to a junction box and then splits off to outlets. I capped everything off inside and tested the breaker. It STILL trips almost immediately. From what everyone is saying that means the line is bad and needs to be replaced, correct? It will be a fair amount of effort to replace it so I want to be sure that will fix it. Are there any other tests I can do to be sure before I yank it back through? When I pull it back, it will have the new line attached to it.

 

NM means non metallic but you are saying metallic. What I think you actually have is old style NM with a metallic like cloth covering. That was never rated for wet locations and therefore should never have been used for direct burial. That may very well be the cause of your problem. It has rotted in the ground and absorbed water.

Is this the type of cable you have:

Source: Wikimedia.org

 

I could not see the full word. Maybe it said NON-metallic. I have cables like the one you show here, but the one going out to the garage is not like that. Here is a picture of it. I measure it out and I need about 65 feet of cable to get there (that's allowing a few feet extra).

 

If that is the cable that is buried underground to your shed than it needs to be replaced. Primarily because it is not rated for wet locations but also because it doesn't seem to have a ground wire.

 

Ok. I kind of figured it was the problem. What kind of cable should I go get?

 

Obviously you will be digging a trench to either remove the old cable and replace with new. I would run PVC conduit from your house to the garage. We can give you more specifics as we go. You would fish THWN wires, through the conduit and establish a subpanel in the garage where you can have 240 volt service, which would tend to future proof the garage and allow you to upgrade tools if necessary.

 

That sounds wonderful but there is no way I can do that. I simply cannot afford it. It currently runs under my paved driveway. It is likely right along the edge of where the blacktop portion meets the concrete pads. So, Plan B, fish through new wire. Is THWN the kind of wire I need?

 

No, THWN is single wires pulled through conduit. You would need cable denoted with UF on the casing, which is for Underground Feeder. How do you plan on running this cable?

 

Yes, if you have some kind of conduit in which to run these wires. I don't see that mentioned in previous posts but may have just missed it....

EDIT: I couldn't figure out how to say what I wanted and Larry got it in ahead of me.

 

From what I can tell there is some kind of conduit already there. I will attach the new cable to the old one and pull it through back to the house. I'm open to other suggestions, but digging it up and replacing it, while preferred, is financially unfeasible for me which is why I'm doing all of this myself to begin with. I really appreciate all of the guidance!

 

You can tunnel under using water or last resort go aerial. Only if you have conduit and it isn't EMT. If you don't have conduit you can't. If it is EMT it is most likely so badly rusted out and caved in as to be unusable.