Household electrical circuit breaker problem

[Godlover]

We re wired our house and used 12 gauge wire and all new breakers, outlets, switches, etc. we used 20 amp Breakers. I have 3 circuits that keep tripping under minimum loads. Tonight I was simply hooking up a dish receiver and the breaker would trip on me. Something isn't right. The work was done by a good friend and he's coming over tomorrow to look at it. Any thoughts.

[Peder_y2k]

Connections are not tight enough. This creates resistance causing breakers to trip.

-Pete, in Tacoma WA USA

[Woody]

how long will the breaker stay closed before it trips?

[IronMike]

20 amp is a little big for standard plugs. 20 AMP is what I have in the ceiling of my Shop for like saws and motor driven 110 things.

Yes loose connections will do this or maybe they have a ground fault plug wired into the circuit. (But that would kick not the breaker) The new plugs have the stab connections, your better off using the screws and really crank on em.

 

My Jacuzzi is 220 on a GFI Circuit breaker and if the slightest thing grounds anything out it trips in a millisecond.

[syscrusher]

Could it be that there is a frig or deep freeze on one of those? Coffee pots, microwaves, and other heating appliances can use a lot of power when they're working. That one breaker probably has several lights and outlets all going back to it. If a couple bigger loads are together then you've got a heavy load, although 20 amp is a heavy breaker. They do make 20 amp GFCI breakers for the panel, if you have one of those tripping then it means that your hot side is being at least partially shunted to ground. In that case they would trip right away unless the shunt is in the equipment that you have plugged in. If you have one of the cheap voltmeters like Harbor Freight gives away you can get some idea by measuring the resistance across the plug (unplugged) for a purely resistive load, motors and some other types of equipment will be a little different, but to draw 20 amps at 110 volts the resistance would be less than about 6 ohms. If you have a cheap clamp on ammeter you can put it over the Romex cable that leads away from that breaker in your box and see if current is being drawn when you think the circuit is idle, but you need to get the cable away from other cables or you may be sensing them as well.

For 12 gauge wire you can use 20 amp breakers but they will then take more of a load to trip. Generally you want the breakers to trip easier unless you will be using heavy shop tools (or high powered audio/video equipment) as Mike indicated.

 

Good luck and have fun!

Edited August 30, 2014 by syscrusher
added

[midnightventure]

Loose connections can create resistance which can cause heat but they will cut amperage. Increased amperage is what causes the breaker to trip. If a connection has come completely loose to the point it creates a short that will increase the amperage and cause the breaker to trip.

[uncledj]

Loose connections can create resistance which can cause heat but they will cut amperage. Increased amperage is what causes the breaker to trip. If a connection has come completely loose to the point it creates a short that will increase the amperage and cause the breaker to trip.

 

If resistance increases, voltage drops, amperage increases. In a situation like a bad connection, the resulting higher amperage will cause the contacts at that connection (weak link) to overheat and potentially burn. It depends on how bad the connection is as to whether it'd trip the breaker or burn the connection apart first.

From the original post, it seems as if maybe you're having a ground fault issue, either with an actual ground, incorrect wiring, or a faulty GFCI, whether it be the breaker itself, or another outlet that is in the circuit. Some houses are wired so that one ground fault outlet will act as a circuit interrupter for other outlets.

Electrical problems can be weird sometimes......I know....I deal with 'em every day.

[Hummingbird]

the first thing I would do is to go to the panel and check the load on the wire coming out of the breaker.

it's a 20 amp and if there's 16 amps or more that circut is overloaded.

[Godlover]

I have Arc breakers due to code and have been reading that they can be a pain. One thing they don't like are older Plasma TVs and that's what is causing the one to trip. I guess will have to pict the 50 inch plasma in my shop! I will check out some of the other suggestions.

[Flyinfool]

I wonder if adding an isolation transformer would filter the plasma enough to prevent tripping the arc fault?

[dacheedah]

12 ga wire with 20 amp breakers is correct, wired the house that way. Grab a circuit tester with three lights and make sure it's wired up right, too loose will cause heat and blow the breaker. The plugs and switches should also be rated for 20a and you can run 14 devices on one circuit. Refrigerator, freezer, washer, dryer get their own circuit as well as the smoke, co alarms, no sharing there. We wire lights to a different circuit than plugs.

 

Next question is did he put in arc fault breakers? Those are required for bedroom outlets and are very sensitive to any spark when plugging devices in.

 

Plugs should also have a ground wire to the box, that won't make it trip but it's code.

 

Breakers can be bad or weak and prematurely trip, swap breakers and if it's still doing it unplug everything on the circuit and then start plugging in devices in one at a time. Remember what you plug in can cause the issue and a short in a cord, in a fan motor. . . can be the issue.

[Flyinfool]

Loose connections can create resistance which can cause heat but they will cut amperage. Increased amperage is what causes the breaker to trip. If a connection has come completely loose to the point it creates a short that will increase the amperage and cause the breaker to trip.

 

 

If resistance increases, voltage drops, amperage increases. In a situation like a bad connection, the resulting higher amperage will cause the contacts at that connection (weak link) to overheat and potentially burn. It depends on how bad the connection is as to whether it'd trip the breaker or burn the connection apart first.

A loose connection will increase resistance and reduce voltage. That much we can all agree on.

 

(WARNING: Semi technical crap to follow)

As to whether amps go up or down from this condition depends on what the load is.

At face value, ohms laws says that as resistance goes up voltage will go down and thus amps will go down. A resistive load like a light will cause lower amp draw in accordance with ohms law.

 

BUT, then you throw in inductance like the windings of a motor and the rules seem to change. An inductive load like a motor will cause an increase in amps. In a motor when voltage is reduced the amps try to go down and this causes the motor to slow down, just like ohms law says it should. But then due to the lower amps the inductance also goes down, in a coil of wire this has the effect of reducing the resistance and makes the amps go up. This is why the more load that you put on a motor the slower it goes and the higher the amps. The reduced voltage is reducing the available horse power effectively increasing the load on the motor and it draws more amps.

 

Some electronics can present both an inductive load and a resistive load in varying amounts of each. It depends on what it is and how it is designed.

 

The heat of a bad connection will only trip the breaker if that bad connection is at the breaker and causes the breaker its self to heat up.

 

Electrical problems can be weird sometimes......I know....I deal with 'em every day.

:sign yeah that:

[BottomFeeder]

In a motor when voltage is reduced the amps try to go down and this causes the motor to slow down, just like ohms law says it should.

In an AC motor, speed is directly related to ac frequency(HZ). In DC motor, speed will be related to volts. For a given HP motor, HP is proportional to volts and amps(v X a). For a given HP, if volts Decreases, amps Increases

[Beau-Kat]

We re wired our house and used 12 gauge wire and all new breakers, outlets, switches, etc. we used 20 amp Breakers. I have 3 circuits that keep tripping under minimum loads. Tonight I was simply hooking up a dish receiver and the breaker would trip on me. Something isn't right. The work was done by a good friend and he's coming over tomorrow to look at it. Any thoughts.

 

Trying to not get too scientific on ya.

 

Was your main breaker panel replaced/upgraded?

 

You say you have 3 circuits tripping. Are they located in one area of the panel, such as being one under the other or side by side? I would assume that with a complete rewire, they did not use any "piggy back" type breakers.

 

In my 30 years as a licensed electrical contractor, I have found that, although these 20 amp piggy back breakers are UL listed, they can transfer heat from one to the other more readily than regular single pole breakers if loaded above about 14 amps or so.

 

Your panel consists of a ground bus, a neutral bus, and two 120VAC buses/legs.

 

One side of your panel has even numbered circuits (poles) and the other side has the odd numbered circuits.

 

As the breakers go down a side of the panel (think circuit numbers 1,3,5,7,9,etc), every other one is fed from the same 120VAC leg. That way a 240VAC breaker, which has one pole situated below the other, feeds from both legs; ie voltage measured between poles #1 and #3 would be 240VAC.

 

Can you tell me the circuit numbers that are tripping? That would identify if they may feed from the same hot leg of the panel.

 

If they feed from different hot legs, and you think the breakers are tripping under very minimal loads, you may possibly have a neutral issue.

 

Could be loose at the service connection, the meter, or the breaker panel.

 

Quite often, people are so concerned with the hot side of the issue that they fail to check the integrity of the neutral part of the circuit.

 

Just fishing for info here to consider a probable cause.

Edited August 31, 2014 by Beau-Kat
added 20 amp to piggy back breakers

[Woody]

I like electrical problems so what did you find. just curious

[uncledj]

The heat of a bad connection will only trip the breaker if that bad connection is at the breaker and causes the breaker its self to heat up.

 

The thing about a bad connection or overloaded wire heating up is that, as it heats, the resistance increases, which causes amperage to go up which will heat the connection / wire up even more,....and it just keeps going until the connection or overloaded wire burns, or the breaker trips.

A typical breaker begins to heat as current passes through it, and when the current exceeds it's rating, it'll trip.

So...my point was.... A bad connection, and the resulting resistance WILL produce heat at that connection when current is draw through it, if that current is greater than the carrying capacity of that bad connection. (Weakest link in the chain)

 

Actually, to be technically correct, I should say that unless you're using a superconductor, any device that uses electricity, or has electricity pass through it will heat. If we're talking about wiring that's sized properly, the heat is negligible, but it's still there.

[Flyinfool]

Ohms law says I = E / R, or Amps = Volts / Resistance.

This is accepted by everyone that knows about electricity.

Amps never go up just because of an increase in resistance.

 

So if a bad connection increases resistance, which we all agree it will. The Amps will go down. Its simple math.

 

It gets confusing when you add inductance, like a motor.

In a motor there are magnetic fields moving all around and creates what is called impedance. Impedance is similar to resistance but only effects AC circuits. It impedes or slows down the electricity. this keeps the motors power consumption down to a safe level. If you lock the shaft of a motor so that it can not turn when the power comes on it will draw a huge amount of amps because you have eliminated the impedance created by the moving magnetic fields.

 

The bottom line is that a bad connection by itself will not increase amps. Some other things on the circuit might increase their amp draw to try to compensate for the reduced voltage of a bad connection which would have the affect of raising amp draw. You can never make the blanket statement that a bad connection will increase amps. It is whats on the circuit that will determine the amp draw.

[Guest tx2sturgis]

 

In an AC motor, speed is directly related to ac frequency(HZ).

 

Not always true. Anyone with a 3-speed ceiling fan knows different.

 

 

Lots of AC motors can have the rotational speed changed with either less voltage applied, or by varying the width of the incoming AC pulses. The AC frequency is not changed at all.

 

Sometimes other things happen, such as excessive heat buildup, or drastically reduced power, or vibration and noise...but they do make AC motor speed controls and they work well in most cases, if used and sized properly.

 

 

 

[Guest tx2sturgis]

 

The thing about a bad connection or overloaded wire heating up is that, as it heats, the resistance increases, which causes amperage to go up which will heat the connection / wire up even more,....and it just keeps going until the connection or overloaded wire burns, or the breaker trips.

 

BUUZZZZZ.

 

Try again...

 

In a basic circuit without impedance, reactance, or inductance involved, if resistance increases, amperage will NOT go up....it will decrease.

 

Ohms law isn't optional....it is a basic law of physics and electricity.

 

You may be thinking about 'thermal runaway' and that CAN happen in certain situations....but its usually due to changing component or connector characteristics when the part is heated...and just gets hotter and hotter due to increasing current which is due to decreasing resistance.

 

 

 

 

 

Edited August 31, 2014 by tx2sturgis

[Flyinfool]

In the context of this thread we are talking about a satellite receiver causing the circuit to trip. That is very different than an induction motor. I do not think it is possible for the dish receiver to pull enough amps to make a bad connection get hot, unless the receiver is defective. As others have mentioned it could be the spark at plugin causing the arc breaker to trip, or it could be a miss-wire causing the breaker to see a current loss and trip. I will be very curious to learn what the final determination is.

 

I hate to hijack threads, But I also hate to see wrong information put out there.

 

In a motor when voltage is reduced the amps try to go down and this causes the motor to slow down, just like ohms law says it should.

 

In an AC motor, speed is directly related to ac frequency(HZ). In DC motor, speed will be related to volts. For a given HP motor, HP is proportional to volts and amps(v X a). For a given HP, if volts Decreases, amps Increases

 

Most of the things on a house circuit are not motors. When you quote me please use the whole explanation. The very next sentence explains why this does not work in this specific case. We disagree on the reasons but do agree on the end result.

 

The heat of a bad connection will only trip the breaker if that bad connection is at the breaker and causes the breaker its self to heat up.

 

The thing about a bad connection or overloaded wire heating up is that, as it heats, the resistance increases, which causes amperage to go up which will heat the connection / wire up even more,....and it just keeps going until the connection or overloaded wire burns, or the breaker trips.

A typical breaker begins to heat as current passes through it, and when the current exceeds it's rating, it'll trip.

So...my point was.... A bad connection, and the resulting resistance WILL produce heat at that connection when current is draw through it, if that current is greater than the carrying capacity of that bad connection. (Weakest link in the chain)

 

Actually, to be technically correct, I should say that unless you're using a superconductor, any device that uses electricity, or has electricity pass through it will heat. If we're talking about wiring that's sized properly, the heat is negligible, but it's still there.

 

I agree with what you say except for the part of increasing resistance increases amps.

Ohms law is widely accepted and says otherwise. That is why it is ohms law and not ohms theory.

 

The bad connection and its heat does NOT increase amps.

SOME (not all) devices that can be connected to a circuit CAN (not will) draw more amps as voltage drops due to increased resistance.

 

Most household breakers are heat tripped. Unless the bad connection is close enough to the breaker to conduct heat into the breaker and cause the breaker to get hot, the bad connection will not trip the breaker.

 

I don't know how many ways to say it. Increased resistance will not increase amps. If it did it would violate the laws of physics as mankind currently understands them.

[Monty]

Not always true. Anyone with a 3-speed ceiling fan knows different.

 

 

Lots of AC motors can have the rotational speed changed with either less voltage applied, or by varying the width of the incoming AC pulses. The AC frequency is not changed at all.

 

 

 

 

I agree with everything except for this. If you change the width of the pulses, you change the time. F=1/T. You will get more or less pulses/second, so frequency changes.

[kevin-vic-b.c.]

back to solving the issue..... as a service tech

 

1. yes what is the load in amps on circuit ... amp-mate to test.

2. is the breaker "bad" ?

3. switch the wire from that breaker to the one above it.... does it still trip?

4. No to #3 swap breaker.... if yes find the appliance causing the tripping

5 take that appliance and connect it to a similarly loaded circuit and try it there.

6 is the appliance faulty?

 

that would be my first service call.

[cowpuc]

back to solving the issue..... as a service tech

 

1. yes what is the load in amps on circuit ... amp-mate to test.

2. is the breaker "bad" ?

3. switch the wire from that breaker to the one above it.... does it still trip?

4. No to #3 swap breaker.... if yes find the appliance causing the tripping

5 take that appliance and connect it to a similarly loaded circuit and try it there.

6 is the appliance faulty?

 

that would be my first service call.

Gotta agree with Kev here. Sounds like some overloading going on.. A short (grounded circuit) is usually instantaneous, overload takes time for the circuit to build heat. I use a clamp on Amp Probe to check amp draw on the circuits.. Work them one at a time, make sure the one your working on has all devices drawing on the circuit at the same time so your getting a reading of max draw.. In the final count, dont forget to make room for motor start ups on any circuits where motors are involved - they (motors) have momentary increase in amp load on start up..

If your amp load reads high compared to the total amp count from specs (to obtain specs, convert wattage to amperage by dividing the stated wattage by voltage = amps (more ohms law stuff), start unplugging stuff and find the culprit causing the high draw.. It is possible that you have some device(s) wired or designed for 220 and your only supplying 110 volts. This would cause a real heavy amp draw..

[midnightventure]

In the context of this thread we are talking about a satellite receiver causing the circuit to trip. That is very different than an induction motor. I do not think it is possible for the dish receiver to pull enough amps to make a bad connection get hot, unless the receiver is defective. As others have mentioned it could be the spark at plugin causing the arc breaker to trip, or it could be a miss-wire causing the breaker to see a current loss and trip. I will be very curious to learn what the final determination is.

 

I hate to hijack threads, But I also hate to see wrong information put out there.

 

 

 

Most of the things on a house circuit are not motors. When you quote me please use the whole explanation. The very next sentence explains why this does not work in this specific case. We disagree on the reasons but do agree on the end result.

 

 

 

I agree with what you say except for the part of increasing resistance increases amps.

Ohms law is widely accepted and says otherwise. That is why it is ohms law and not ohms theory.

 

The bad connection and its heat does NOT increase amps.

SOME (not all) devices that can be connected to a circuit CAN (not will) draw more amps as voltage drops due to increased resistance.

 

Most household breakers are heat tripped. Unless the bad connection is close enough to the breaker to conduct heat into the breaker and cause the breaker to get hot, the bad connection will not trip the breaker.

 

I don't know how many ways to say it. Increased resistance will not increase amps. If it did it would violate the laws of physics as mankind currently understands them.

 

There is no getting around Ohm's law. Peril of the internet. People that have never had an electronics class jumping in with misinformation. Thank you for trying to slow down the misinformation.

[uncledj]

I think the misunderstanding here is that your're discussing electronics, whereas I'm discussing electromechanical equipment.

A common example would be a contactor that overloads will burn the contact points. If it's not replaced, it'll continue to burn the contacts until they either weld, or burn so badly they won't pass current.

I saw where someone mentioned the difference between types of loads. Pretty much everything I deal with runs a motor of some sort, (inductive load) although I do see the same scenario with electric strip heat, which I believe is a resistive load.

It may also be the misunderstandings that occur between applications, which can change things quite a bit from theory or, in this case OHMS law, and actual situations in the field.

I don't want to misinform anyone, but I know what I know....from 26 years of working with it and seeing it nearly every day.

Once a contact becomes poor,...that contact heats, and will continue to heat until it fails. I stand by that. If you try to run too much current through a wire, it'll heat until it burns, which is why you need breakers or fuses to protect the wiring / property / life in the first place.

I'm just sayin'

But....back to the problem. I saw someone mentioned arc flash breakers that may be reacting to a plasma TV. Now that's interesting, and something I can't speak to, but certainly seems to make sense.