I went over to help a buddy with a 15 amp circuit he had trip over the weekend. Its on a 15 amp single pole tandem breaker. The circuits has loads such as his TV, computer, and about 4-6 can lights(so basically around 5 receps and 6 can lights controlled by 2 dimmer switches) . The breaker was in the tripped position when I got there, so I cycled it off then I tried to switch it back on and working a second it hummed then tripped. Tried it a few more times with the same results. I removed the circuit and applied it to the second 15amp breaker of the tandem and the same thing happened, a hum noise then a trip all within 2 seconds max. I put another working 15 amp circuit on it to make sure the breaker wasnt bad and sure enough it energized and held and was reading 120v to ground on the load side. I also moved the circuit to another single pole 15 amp breaker that wasnt a tandem to make sure it wasnt just the whole breaker itself and sure enough it tripped that breaker as well so its either a short or an overlord. He said he hasnt added anything at all to the circuit to make it overload. I asked if hes driven any screws or nails into the walls as well Incase he may have hit the Romex and that was ruled out. So I unplugged all of the loads, even removed a few of the receptacles and just wired the wires together to see if I could get the circuit breaker to hold, but no luck. I checked for continuity at the recaps and I was reading it but that could be because its getting the continuity from the can lights. So I pretty much ruled out an overload of the circuit, and now onto finding a short. We only had 30 minutes to mess around with it today but I will be going back tom. My plan is to find the home run of the circuit coming into the nearest receptacle to the panel id imagine and identify it and take any load off it and see if the breaker energizes and holds and reads 120v to ground. If I get that far then I will start attaching load by load down the stream until I find out which load is tripping the circuit. Any advice would help and be greatly appreciated. Should I remove the bulbs in the can lights to remove more power draw or that being the possibility of the short?

On Monday, April 20, 2020 at 11:49:29 PM UTC-4, wrote:
I went over to help a buddy with a 15 amp circuit he had trip over the weekend. Its on a 15 amp single pole tandem breaker. The circuits has loads such as his TV, computer, and about 4-6 can lights(so basically around 5 receps and 6 can lights controlled by 2 dimmer switches) . The breaker was in the tripped position when I got there, so I cycled it off then I tried to switch it back on and working a second it hummed then tripped. Tried it a few more times with the same results. I removed the circuit and applied it to the second 15amp breaker of the tandem and the same thing happened, a hum noise then a trip all within 2 seconds max. I put another working 15 amp circuit on it to make sure the breaker wasnt bad and sure enough it energized and held and was reading 120v to ground on the load side.. I also moved the circuit to another single pole 15 amp breaker that wasnt a tandem to make sure it wasnt just the whole breaker itself and sure enough it tripped that breaker as well so its either a short or an overlord. He said he hasnt added anything at all to the circuit to make it overload. I asked if hes driven any screws or nails into the walls as well Incase he may have hit the Romex and that was ruled out. So I unplugged all of the loads, even removed a few of the receptacles and just wired the wires together to see if I could get the circuit breaker to hold, but no luck. I checked for continuity at the recaps and I was reading it but that could be because its getting the continuity from the can lights. So I pretty much ruled out an overload of the circuit, and now onto finding a short. We only had 30 minutes to mess around with it today but I will be going back tom. My plan is to find the home run of the circuit coming into the nearest receptacle to the panel id imagine and identify it and take any load off it and see if the breaker energizes and holds and reads 120v to ground. If I get that far then I will start attaching load by load down the stream until I find out which load is tripping the circuit. Any advice would help and be greatly appreciated. Should I remove the bulbs in the can lights to remove more power draw or that being the possibility of the short?

With the light switch off, the lights should not be a factor. With a tandem breaker, it must be a shared neutral circuit, so be aware of that. Any chance there is another receptacle/load on the circuit that's not obvious? Sounds like you are on the right track. I would take a look at all the boxes first, pull the receptacles, switches out, see if anything is obvious.

On 4/20/20 10:49 PM, wrote:

I went over to help a buddy with a 15 amp circuit he had trip over the weekend. Its on a 15 amp single pole tandem breaker. The circuits has loads such as his TV, computer, and about 4-6 can lights(so basically around 5 receps and 6 can lights controlled by 2 dimmer switches) . The breaker was in the tripped position when I got there, so I cycled it off then I tried to switch it back on and working a second it hummed then tripped. Tried it a few more times with the same results. I removed the circuit and applied it to the second 15amp breaker of the tandem and the same thing happened, a hum noise then a trip all within 2 seconds max. I put another working 15 amp circuit on it to make sure the breaker wasnt bad and sure enough it energized and held and was reading 120v to ground on the load side. I also moved the circuit to another single pole 15 amp breaker that wasnt a tandem to make sure it wasnt just the whole breaker itself and sure enough it tripped that breaker as well so its either a short or an overlord. He said he hasnt added anything at all to the circuit to make it overload. I asked if hes driven any screws or nails into the walls as well Incase he may have hit the Romex and that was ruled out. So I unplugged all of the loads, even removed a few of the receptacles and just wired the wires together to see if I could get the circuit breaker to hold, but no luck. I checked for continuity at the recaps and I was reading it but that could be because its getting the continuity from the can lights. So I pretty much ruled out an overload of the circuit, and now onto finding a short. We only had 30 minutes to mess around with it today but I will be going back tom. My plan is to find the home run of the circuit coming into the nearest receptacle to the panel id imagine and identify it and take any load off it and see if the breaker energizes and holds and reads 120v to ground. If I get that far then I will start attaching load by load down the stream until I find out which load is tripping the circuit. Any advice would help and be greatly appreciated. Should I remove the bulbs in the can lights to remove more power draw or that being the possibility of the short?


Can you go halfway down the circuit distance wise and unhook
everything down stream? Does the breaker trip then?

On 4/20/20 11:49 PM, wrote:

I went over to help a buddy with a 15 amp circuit he had trip over the weekend. Its on a 15 amp single pole tandem breaker. The circuits has loads such as his TV, computer, and about 4-6 can lights(so basically around 5 receps and 6 can lights controlled by 2 dimmer switches) . The breaker was in the tripped position when I got there, so I cycled it off then I tried to switch it back on and working a second it hummed then tripped. Tried it a few more times with the same results. I removed the circuit and applied it to the second 15amp breaker of the tandem and the same thing happened, a hum noise then a trip all within 2 seconds max. I put another working 15 amp circuit on it to make sure the breaker wasnt bad and sure enough it energized and held and was reading 120v to ground on the load side. I also moved the circuit to another single pole 15 amp breaker that wasnt a tandem to make sure it wasnt just the whole breaker itself and sure enough it tripped that breaker as well so its either a short or an overlord. He said he hasnt added anything at all to the circuit to make it overload. I asked if hes driven any screws or nails into the walls as well Incase he may have hit the Romex and that was ruled out. So I unplugged all of the loads, even removed a few of the receptacles and just wired the wires together to see if I could get the circuit breaker to hold, but no luck. I checked for continuity at the recaps and I was reading it but that could be because its getting the continuity from the can lights. So I pretty much ruled out an overload of the circuit, and now onto finding a short. We only had 30 minutes to mess around with it today but I will be going back tom. My plan is to find the home run of the circuit coming into the nearest receptacle to the panel id imagine and identify it and take any load off it and see if the breaker energizes and holds and reads 120v to ground. If I get that far then I will start attaching load by load down the stream until I find out which load is tripping the circuit. Any advice would help and be greatly appreciated. Should I remove the bulbs in the can lights to remove more power draw or that being the possibility of the short?


See that big key on the right hand side of your keyboard marked "Return"
of "Enter"?

Try hitting it once in a while to make paragraphs so people can read
your post ;-)

--
The big divide in this country is not between and Democrats and
Republicans or women and men, but between talkers and doers.
- Thomas Sowell

On 4/21/2020 6:39 AM, Wade Garrett wrote:
On 4/20/20 11:49 PM, wrote:
I went over to help a buddy with a 15 amp circuit he had trip over the
weekend. Its on a 15 amp single pole tandem breaker. The circuits has
loads such as his TV, computer, and about 4-6 can lights(so basically
around 5 receps and 6 can lights controlled by 2 dimmer switches) .
The breaker was in the tripped position when I got there, so I cycled
it off then I tried to switch it back on and working a second it
hummed then tripped. Tried it a few more times with the same results.
I removed the circuit and applied it to the second 15amp breaker of
the tandem and the same thing happened, a hum noise then a trip all
within 2 seconds max. I put another working 15 amp circuit on it to
make sure the breaker wasnt bad and sure enough it energized and held
and was reading 120v to ground on the load side. I also moved the
circuit to another single pole 15 amp breaker that wasnt a tandem to
make sure it wasnt just the whole breaker itself and sure enough it
tripped that breaker as well so its either a short or an overlord. He
said he hasnt added anything at all to the circuit to make it
overload. I asked if hes driven any screws or nails into the walls as
well Incase he may have hit the Romex and that was ruled out. So I
unplugged all of the loads, even removed a few of the receptacles and
just wired the wires together to see if I could get the circuit
breaker to hold, but no luck. I checked for continuity at the recaps
and I was reading it but that could be because its getting the
continuity from the can lights. So I pretty much ruled out an overload
of the circuit, and now onto finding a short. We only had 30 minutes
to mess around with it today but I will be going back tom. My plan is
to find the home run of the circuit coming into the nearest receptacle
to the panel id imagine and identify it and take any load off it and
see if the breaker energizes and holds and reads 120v to ground. If I
get that far then I will start attaching load by load down the stream
until I find out which load is tripping the circuit. Any advice would
help and be greatly appreciated. Should I remove the bulbs in the can
lights to remove more power draw or that being the possibility of the
short?

See that big key on the right hand side of your keyboard marked "Return"
of "Enter"?

Try hitting it once in a while to make paragraphs so people can read
your post ;-)
Indeed!

Something went bad on a circuit that used to work.

Could be any of the appliances on receptacles. But you unplugged them.

Could be a short in a receptacle. I've seen it, but rarely. In my limited experience these tend not to behave like an overload, but like a short. Your symptoms sound like overload rather than short. Same for wiring.

Can't be a short in a bulb. Those usually just blow.

So, what's left? The dimmer. That is the first place I'd look. I've seen a lot of these go bad.

Why start at the breaker? I usually start at the other end.

In article ,
says...

Something went bad on a circuit that used to work.

Could be any of the appliances on receptacles. But you unplugged them.

Could be a short in a receptacle. I've seen it, but rarely. In my limited experience these tend not to behave like an overload, but like a short. Your symptoms sound like overload rather than short. Same for wiring.

Can't be a short in a bulb. Those usually just blow.

So, what's left? The dimmer. That is the first place I'd look. I've seen a lot of these go bad.

Why start at the breaker? I usually start at the other end.



The first thing to do is unplug if possiable and turn off everything on
the circuit. Then instead of just flipping the breaker back on more
than once, use an ohm meter to check the circuit for a short. If none
found, turn the breaker back on and test each device before you turn it
on or plug it in. just do one at a time. sooner or later you will find
the defective device. It does help to have an amp meter to actually see
how much current is being used as the devices are turned back on.

If breakers are continiously turned on and tripped it won't be long
before the breaker will fail or be weakened.

Lowes has some test meters for around $ 50 and I am sure other stores
have the same or similar.

On Tuesday, April 21, 2020 at 1:19:57 PM UTC-4, Ralph Mowery wrote:
If breakers are continiously turned on and tripped it won't be long
before the breaker will fail or be weakened.


I had to look this up sometime back and I've probably posted the exact numbers.

But it turns out a breaker can trip on a mild overload quite a lot of times, many thousands.

A direct short is another matter. On average you get only 2 tries before failure, and it might be the 1st time.

The last time we had this discussion it was a handyman electrician recommending his method for figuring out what breaker an outlet was on. He put together a plug with the prongs hard wired together. Then he would plug it in and go look for the breaker that had tripped. I was then and remain horrified at that idea. Clearly it would work, but you're stressing every part of that circuit.

On Tue, 21 Apr 2020 09:51:09 -0700 (PDT), TimR
wrote:

Something went bad on a circuit that used to work.

Could be any of the appliances on receptacles. But you unplugged them.

Could be a short in a receptacle. I've seen it, but rarely. In my limited experience these tend not to behave like an overload, but like a short. Your symptoms sound like overload rather than short. Same for wiring.

Can't be a short in a bulb. Those usually just blow.

Don't bet the farm on it. I've had nimerous 12 volt automotive bulbs
short, and a few 120 volt incandescents. Had one Compact flourescent
that would pop fuses.

So, what's left? The dimmer. That is the first place I'd look. I've seen a lot of these go bad.

And I've NEVER seen one short to ground. Generally the blow open, and
if they fail closed they just keep the lights on.

Why start at the breaker? I usually start at the other end.

Generally start in the middle of the circuit, then in the middle of
the sector that fails. Most likely cause is a black wire shorted to
grounf - like a wire nut fell off - or a wire pinched. Is it Romex or
sheilded cable or conduit???

On Tuesday, April 21, 2020 at 3:17:27 PM UTC-4, Clare Snyder wrote:
the sector that fails. Most likely cause is a black wire shorted to
grounf - like a wire nut fell off - or a wire pinched. Is it Romex or
sheilded cable or conduit???

Now I'll predict the worst case.

He'll go back tomorrow filled with our suggestions - and nothing he can do will get the breaker to trip again.

I hate it when that happens.

In article ,
says...

Why start at the breaker? I usually start at the other end.

Generally start in the middle of the circuit, then in the middle of
the sector that fails. Most likely cause is a black wire shorted to
grounf - like a wire nut fell off - or a wire pinched. Is it Romex or
sheilded cable or conduit???



I would agree start in the middle and work by halfs , but in many
houses it is hard to know where the middle is.

On Tuesday, April 21, 2020 at 3:17:27 PM UTC-4, Clare Snyder wrote:
On Tue, 21 Apr 2020 09:51:09 -0700 (PDT), TimR
wrote:

Something went bad on a circuit that used to work.

Could be any of the appliances on receptacles. But you unplugged them.

Could be a short in a receptacle. I've seen it, but rarely. In my limited experience these tend not to behave like an overload, but like a short. Your symptoms sound like overload rather than short. Same for wiring.

Can't be a short in a bulb. Those usually just blow.

Don't bet the farm on it. I've had nimerous 12 volt automotive bulbs
short, and a few 120 volt incandescents. Had one Compact flourescent
that would pop fuses.

Did you ever see it with the light switch off?




So, what's left? The dimmer. That is the first place I'd look. I've seen a lot of these go bad.

And I've NEVER seen one short to ground. Generally the blow open, and
if they fail closed they just keep the lights on.

Why start at the breaker? I usually start at the other end.

Generally start in the middle of the circuit, then in the middle of
the sector that fails. Most likely cause is a black wire shorted to
grounf - like a wire nut fell off - or a wire pinched. Is it Romex or
sheilded cable or conduit???

On Tue, 21 Apr 2020 17:04:24 -0400, Ralph Mowery
wrote:

In article ,
says...

Why start at the breaker? I usually start at the other end.

Generally start in the middle of the circuit, then in the middle of
the sector that fails. Most likely cause is a black wire shorted to
grounf - like a wire nut fell off - or a wire pinched. Is it Romex or
sheilded cable or conduit???



I would agree start in the middle and work by halfs , but in many
houses it is hard to know where the middle is.


Not if you know what all is on the circuit and think like an
electrician. Throw a fox and hound into the equation and it becomes
pretty trivial to figure it out (an active signal tracer)

On 4/21/20 2:12 PM, TimR wrote:

[snip]

The last time we had this discussion it was a handyman electrician recommending his method for figuring out what breaker an outlet was on. He put together a plug with the prongs hard wired together. Then he would plug it in and go look for the breaker that had tripped. I was then and remain horrified at that idea. Clearly it would work, but you're stressing every part of that circuit.

How about a device that creates a 100% overload (like 40A on a 20A
breaker), which is a lot less than infinite? Still don't leave it
connected more than a second or so.

--
"The truth cannot be asserted without denouncing the falsehood." --
Leslie Stephen

On Wednesday, April 22, 2020 at 4:43:13 PM UTC-4, Sam E wrote:
On 4/21/20 2:12 PM, TimR wrote:

[snip]

The last time we had this discussion it was a handyman electrician recommending his method for figuring out what breaker an outlet was on. He put together a plug with the prongs hard wired together. Then he would plug it in and go look for the breaker that had tripped. I was then and remain horrified at that idea. Clearly it would work, but you're stressing every part of that circuit.

How about a device that creates a 100% overload (like 40A on a 20A
breaker), which is a lot less than infinite? Still don't leave it
connected more than a second or so.

--
"The truth cannot be asserted without denouncing the falsehood." --
Leslie Stephen

How would you do that? Buy a big toaster? Daisy chain a half dozen hair dryers?

I thought of hardwiring a 30A breaker and plugging that in, but there's no guarantee it wouldn't trip first.

At any rate, the original poster has ghosted us, we'll never know what is wrong, so we can all confidently claim to have been right.

He should also ask his friend if he has put any nails / screws in the walls etc to hang pictures

On 4/21/2020 2:12 PM, TimR wrote:
On Tuesday, April 21, 2020 at 1:19:57 PM UTC-4, Ralph Mowery wrote:
If breakers are continiously turned on and tripped it won't be long
before the breaker will fail or be weakened.


I had to look this up sometime back and I've probably posted the exact numbers.

But it turns out a breaker can trip on a mild overload quite a lot of times, many thousands.

A direct short is another matter. On average you get only 2 tries before failure, and it might be the 1st time.
....

????

--

On Thu, 7 May 2020 13:53:31 -0500, dpb wrote:

On 4/21/2020 2:12 PM, TimR wrote:
On Tuesday, April 21, 2020 at 1:19:57 PM UTC-4, Ralph Mowery wrote:
If breakers are continiously turned on and tripped it won't be long
before the breaker will fail or be weakened.


I had to look this up sometime back and I've probably posted the exact numbers.

But it turns out a breaker can trip on a mild overload quite a lot of times, many thousands.

A direct short is another matter. On average you get only 2 tries before failure, and it might be the 1st time.
...

????
A decent breaker should protect against a short circuit numerous
times. The short circuit trip is MAGNETIC.

On the other hand, a breaker that has tripped due to repeated
overloads will deteriorate because the overload trip is thermal. Even
running "on the edge" repeatedly will cause a breaker to eventually
fail (usually causing it to trip prematurely unless it's a FPC/FPE
breaker)

On Thursday, May 7, 2020 at 10:36:38 AM UTC-5, Mark wrote:
He should also ask his friend if he has put any nails / screws in the walls etc to hang pictures
Nothing like a nail driven through a wire to cause a short

On Friday, May 8, 2020 at 11:48:16 AM UTC-4, Clare Snyder wrote:
A decent breaker should protect against a short circuit numerous
times. The short circuit trip is MAGNETIC.

On the other hand, a breaker that has tripped due to repeated
overloads will deteriorate because the overload trip is thermal. Even

I've seen it argued both ways. Very possible over the years I've argued it both ways. I found this snip in a similar thread some years back:
****
One Square D breaker I found data for was rated at 12,500 cycles mechanical operation (meaning you turned it off by hand) and 2,800 electrical operation (meaning it overloaded but did NOT fault). I would think mechanical operation would depend on how much current was being drawn at the time, and I always try to turn off loads before flipping a breaker just in case. We had a nasty explosion in the plant once when somebody flipped a disconnect under load.

I could not find the fault rating for that breaker but several other searches said a breaker is guaranteed to interrupt the full fault current (meaning a short) ONCE, and should be replaced after twice.
*****

On 5/8/2020 12:17 PM, TimR wrote:
On Friday, May 8, 2020 at 11:48:16 AM UTC-4, Clare Snyder wrote:
A decent breaker should protect against a short circuit numerous
times. The short circuit trip is MAGNETIC.

On the other hand, a breaker that has tripped due to repeated
overloads will deteriorate because the overload trip is thermal. Even

I've seen it argued both ways. Very possible over the years I've argued it both ways. I found this snip in a similar thread some years back:
****
One Square D breaker I found data for was rated at 12,500 cycles
mechanical operation (meaning you turned it off by hand) and 2,800
electrical operation (meaning it overloaded but did NOT fault). I
would think mechanical operation would depend on how much current was
being drawn at the time, and I always try to turn off loads before
flipping a breaker just in case. We had a nasty explosion in the
plant once when somebody flipped a disconnect under load.

Not on just a small household circuit type load nor a household-sized
breaker, either, I'll bet.

I could not find the fault rating for that breaker but several other
searches said a breaker is guaranteed to interrupt the full fault
current (meaning a short) ONCE, and should be replaced after twice.
*****

I'm having a hard time believing a manufacturer would say that on a
household-sized breaker, sorry.

I've never seen one replaced because of a short-circuit trip and never
heard one failing in such a fashion after.

--