I have a problem with an electrical circuit in my house. I have a
circuit where the breaker trips repeatedly, but not immediately when I
flip it back on. What I mean is this; I see that the breaker has
tripped, so I flip it back on. After 4 or 5 minutes, the breaker is
invariably trip again. It never trips immediately, but there is that
gap of time between when I turn it on and it trips.
The circuit is barely loaded. Straight from the breaker is an outlet
in the garage (where I usually plug in my water softener but I don't
have one at the moment). From there, the wire goes outside and is
buried all the way to a shed. I have enclosed the buried wired in that
grey conduit all the way from the outside of the house into the shed.
In the shed, I have four outlets (with rarely anything plugged in
unless I'm weed-whacking or something) and four switches going to four
lights. That's it.
I've wondered (and dread) that there's a short somewhere in the outside
part of the wire but I don't know why the breaker wouldn't trip
immediately after I flip it back on. Could it be the breaker is no
good. Any thoughts on the best way I could begin testing where the
Thanks in advance for any advice. I greatly appreciate anyone's help!
You could remove the wire from the breaker and put the breaker back in and
flip it on to see if it still trips after 4-5 minutes. If not, then I
think the breaker would be good but the best time is as stated earlier,
exchange it with another breaker of the same Amperage.
Tripping a short time after flipping it back on
indicates either a bad breaker but or, more
likely, a load that is very close to the maximum
allowed by the breaker. As others suggest, with
the breaker off, go to that last outlet and
disconnect the wire that goes underground, then
flip the breaker on and see how long it takes, if
ever, for the breaker to flip off. If it flips
off, reconnect in the garage, and disconnect the
wire in the shed at the first connections. That
way you will be able to figure out if the problem
is the underground wire or something in the shed.
You would hate to dig up the wire and find the
problem to be something in the shed. Probably
gophers, ground squirrels, etc. munching on the wire.
measure zero amps from the breaker load screw to the disconnected load
wire with all devices off.
or replace the breaker with the same amperage gfi breaker.
or maybe unplug the electric heater the kids have in the shed.
Watch your meter while resetting the breaker (or have someone else watch
the meter) to see if it starts spinning faster when you turn the circuit
on. If there's a mystery load large enough to trip the breaker, you
should see a difference in consumption.
Any circuit protection device that works on an overload state is spec'd
at a certain time delay at a certain load. (that includes fuses) ie if
its a 15A breaker it might trip after 30 seconds at 15A or 3 seconds at
18A. Dead short (lots of amps) situations will give an immediate trip.
(Note these times are guesses!)
Keep in mind that many breakers nowadays are core balance as well as
overload. ie they look at the current difference between inbound and
outbound (eg a phase and neutral) Any disparity usually means an earth
flow (like through a human body) hence it trips. Pretty well all medical
equipment running on mains has this protection.
Assuming the breaker isnt faulty I would assume you have a load just
over its rating. It is conceivable you have attached it also to a device
that doesnt try to power up immediately (eg some high power heating)
What have you got attached to the circuit the breaker is protecting?
First, thanks for all the help and advice from all of you.
Second, I was finally able to spend some time on this problem
yesterday. I measured and disconnected this and that wire just like
the advice above. I also switched the circuit to other breakers, etc.
I'm certain that the problem lies in the wire that is buried (the very
result I dreaded). I even ran a parallel wire from the breaker box to
the shed above ground to see what would happen (~50') and the breaker
What I didn't try, yet, was the advice about measuring the amperage on
the circuit with a meter. I'm going to do that, still, because now I'm
interested. I'll let you all know.
Again, thanks for the help!
PS - now that I'm facing the prospect of digging (again), has anyone
ever found a less torturous method of removing sod WITHOUT a sod
kicker. I think I'd rather pull out my fingernails next time than use
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