Household electrical circuit breaker problem

[Freebird]

Folks, I was an industrial electrician for more than 20 years. I worked with all types of loads and voltages from 12VDC control circuits to 7160 Volt AC motors and everything in between. Inductive loads and resistive loads.

 

Now it's been more than 20 years since I worked as an electrician and I readily admit that I have forgotten a lot of stuff but I simply don't agree that increasing resistance will not increase amps. Of COURSE it will.

 

I completely understand OHMS law but what is being left out here is that the source of power will strive to supply the stated voltage and therefore drive the amps higher. Take a simple light bulb as an example. A 100 watt light bulb and a 40 watt light bulb both have 120 volts supplied to them. The only difference is the resistive element of the bulb. The 100 watt bulb will draw more amps because it has a higher resistant element. Same thing with a standard electric strip heater. A 10,000 watt heater draws more amps than a 5000 watt heater simply because it has higher resistant coils. Both have 120 volts supplied to them but the increased resistance causes the 10,000 watt heater to draw more amps.

 

So if you have a loose connection or anything else that increase resistance, the power source will adjust to continue providing 120 volts to whatever it is so as the resistance increases, so will the amperage. It is not in any way violating OHMS law. OHMS law still applies but as the resistance increases and the power adjusts to continue supplying the stated voltage, of course the amperage is going to increase.

 

So yes, increased resistance usually WILL result in higher amperage unless the power supply is unable to provide the specified voltage.

[uncledj]

I added the last post about 10 minutes ago, and it prompted me to "google" the issue, and I realized where the difference lies.

When the contact is poor, or wire undersized, the voltage is dropping, and THAT is what causes the increased amperage, causing a catch 22. Poor contact causes voltage drop, which causes higher amperage, which causes heating and increased resistance, which causes further voltage drop, which causes higher current draw.

HMMM....I'm seeing a pattern here.

It sounds like a cop out, but I think the situation is that we're all right. The variables of the experiment are changing.

Anyhoo, I'm done.

Peace out

[midnightventure]

Freebird

You are a bright guy and I have developed a lot of respect for you through the years but a higher wattage bulb is going to have less resistance. The funny part is that an old fashioned incandescent bulb changes resistance as it heats up. Very quickly but it changes. That is why when they get old they are more likely to burn out when you first flip the switch. At the temperature 100 watt bulb is going to operate at the resistance is 144 ohms. A 60 watt operates at 240 ohms. If you measure the resistance on a cold bulb the resistances will be much less. Of course all this doesn't help the original poster.

Edited August 31, 2014 by midnightventure

[Godlover]

Replaced the Plasma with my man cave LED and the circuit has been fine. We determined that the circuit that had the bathroom exhaust, bedroom ceiling fan, and several lights needs to be separated into two circuits. The third hasn't kicked out since we moved in. Figured it was the air compressor doing it. They are arc breakers and much more sensitive. Thanks for the info!

[Freebird]

Freebird

You are a bright guy and I have developed a lot of respect for you through the years but a higher wattage bulb is going to have less resistance. The funny part is that an old fashioned incandescent bulb changes resistance as it heats up. Very quickly but it changes. That is why when they get old they are more likely to burn out when you first flip the switch. At the temperature 100 watt bulb is going to operate at the resistance is 144 ohms. A 60 watt operates at 240 ohms. If you measure the resistance on a cold bulb the resistances will be much less. Of course all this doesn't help the original poster.

 

You are 100% correct of course. I TOLD you it had been a LONG time. Forget everything I said.

[Flyinfool]

I am not sure what all a plasma TV can feed back into the line.

Hence my post way up in this thread.

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

 

You are 100% correct of course. I TOLD you it had been a LONG time. Forget everything I said.

 

Forget what?????

[Peder_y2k]

We determined that the circuit that had the bathroom exhaust, bedroom ceiling fan, and several lights needs to be separated into two circuits.

 

A bath fan, plus a ceiling fan and several lights should NOT reguire two circuits. Those should not exceed 15Amps if run all at once. Something else is/was not right.

 

-Pete, in Tacoma WA USA

[MikeWa]

It is called an amp meter. Put one on the circuit and find out what is going on.

 

Mike

[Guest tx2sturgis]

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.

 

 

Hate to nitpick...but no, I am correct. You can vary pulse width of a 60hz sinewave, thats exactly how a common triac-based lamp dimmer works. The frequency of the pulses stay the same, but some parts of each pulse are .....'removed'....switched off....and so the motor slows down (or the lamp gets dimmer) since it has less power to run it.

 

First image is a normal sine wave. Second image is a sine wave modified using pulse 'modification' (or modulation)...commonly refered to as PWM....and is a very cheap and common way of regulating small motors like fans, built using small induction motors, shaded-pole motors, and incandescent lamps.

 

The applied frequency, usually 60 hz in the USA...remains 60hz. There is no way to change it...not with a simple pulse width controller.

 

BTW...synchronous motors, like clock motors, DO rotate in synch with the applied AC frequency....but others, like induction and shaded-pole motors can vary in speed regardless of the AC frequency.

 

Of course, if we begin discussing high power industrial electric motors (or brush-type motors) running on single or 3 phase AC....then some of these facts dont apply...but we ARE talking about common household appliances...not factory machinery.

 

Edited September 1, 2014 by tx2sturgis

[IronMike]

And i was just about to award Freebird the Electrical Contract on my remodel job!

[Hummingbird]

Good Goilly - the man has a breaker that is tripping for an unknown reason.

By using an amp meter he can find out how many amps are being used on that circuit. If the amperage is within regulated parameters then a motor (frige compressor ?) could possibly be the culprit or any number of things.

I'm relatively sure that the ballast bortle tank pressure has no bearing on tripping the breaker.What ever happened to basic trouble shooting ?

Also, as soon as the electrical inspection is over and approved - well

[dacheedah]

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.

 

I have learned a bunch by attending fire chief's meetings. NEC has expanded the use of arc faults because they found several protective devices ie smoke alarms circuits and secondary circuits like roof fans . . . causing fires in unattended areas. Some older technology and devices were designed when this was not a consideration, so as we upgrade and hopeful make our homes a safer place we must also upgrade our tools and comfort items.

 

Kinda like riding a third gen . . .:stirthepot: