Ask me electrical questions please! You'll be helping me out!

[GloomCookie]

Hi everyone!

I am studying for my Professional Engineering (PE) license for power distribution, and as part of my studies I thought I'd help you guys out by offering to answer questions about electricity. Basically trying to translate the complex engineering principles that I'm studying into a way that you, the average person, can understand. This also means I have to know enough about the material to break it down, so it'll help identify any areas I'm weak in.

So, if you have questions about how electrical or engineering works, please ask!

[Inkidu]

Sure:

What is Ohm's Law and why is it fundamentally important to electrical mechanics?

Also, explain the differences between amps, watts, and volts, and in what combinations and at what levels are they most dangerous to the average person should they not practice electrical safety?

[GloomCookie]

Sure:

What is Ohm's Law and why is it fundamentally important to electrical mechanics?

Also, explain the differences between amps, watts, and volts, and in what combinations and at what levels are they most dangerous to the average person should they not practice electrical safety?

Hi Inkidu! Thank you very much for your question!

So Ohm's Law is one of the first lessons we learn in electrical mechanics because it's so fundamental to everything. DC power, AC power, Ohm's Law works. In it's most simple form, it's simply the equation Voltage is equal to Amperage times Resistance, but that is only true for DC power. Once you move into AC power, it changes somewhat because we get into more complicated mechanics, but it is still fundamentally the same, we just call it Complex Voltage is equal to Complex Amperage times Impedance. And honestly, the reason it is so fundamental is because you are guaranteed to have at least two of those variables on hand in any situation involving electrical design and circuit analysis.



As far as Watts, Amps, and Volts go, this gets a little complex so please bear with me.

Voltage is also known as potential. It's how much effort an individual electron is willing to expend to get from here to there. More voltage means that electron has a lot more push behind it when it decides to get going. AC power does alternate back and forth but there is still some forward momenetum once electrons start moving, which is where amperage comes in.

Amps is the measure of how many electrons are moving at a particular moment in time, and like voltage in an AC system can flow backwards and forwards, but generally there is some flow from higher potential to lower potential. Amperage is also responsible for generating magnetic fields within wires. Even a straight wire generates a magnetic field, albiet a small one, but when you wrap the wire tightly you can create a much stronger magnetic field, which is the basis for motors and transformers.

Watts is the common term for the amount of power used by the system, and is simply voltage times amperage. If it were that simple, however, I'd be out of a job.

Where it gets complicated is that in an AC system, voltage and current are not always syncronized. In most cases, current lags behind voltage due to the load having an impedance that sort of traps some of the current due to its own magnetic field. In essence, magnetic fields really don't like sudden changes (which is the basis of a thing called Lens' Law) which means that it takes a bit for the magnetic field to break down and change direction. This lagging introduces a complex component into the system, which is why Watts is only part of the total electrical usage. It's essentially the 'real' power being used, while complex power is the total taken up by the system at any given time.

So if Watts are only part of the system, why do we still use things like a 60W lightbulb? Because while Wattage is only part of the total system, it's also the easiest to measure. The power company on most residences only worries about wattage, since they can use a fairly cheap meter to do the job and most houses fall into a standard efficiency called 'power factor'. Power factor is the ratio of 'real' power to complex power and how efficient the system overall is. That relationship is Total Power is the Real Power (Watts) divided by power factor. For commercial and industrial customers, it's not uncommon for the power company to charge more money if their system is inefficient, and may even require they take corrective action to bring their power factor closer to 100%.



Now, on to the dangers of electricity. Yes, electricity is extremely dangerous if you don't know what you're doing. My recommendation when it comes to anything electrical is that if you don't know what you're doing, step away and let someone who does handle it. Seriously, there's a reason I have a mug with the following cartoon on it. I could get into the particulars, but just stay the hell away if you're not sure.

Remember kids, electricity will kill you!

[Beorning]

I have two questions:

1. Why does the magnetic field generated by a wire get stronger, if you wrap the wire into a coil?

2. What's the difference between AC and DC? Also, why was Tesla right and Edison wrong?

[GloomCookie]

I have two questions:

1. Why does the magnetic field generated by a wire get stronger, if you wrap the wire into a coil?

2. What's the difference between AC and DC? Also, why was Tesla right and Edison wrong?

Hi Beorning!

So in the case of magnetic fields, magnetic fields curl about themselves, which is why on a magnet the lines exit the northern pole and go around to the southern pole. By wrapping the wire in a coil, the small and weak magnetic field builds on itself and becomes stronger.

As far as AC vs DC, that one is less that Tesla was right and Edison was wrong and more that Tesla is handy for what we call line or mains voltage and DC is better for specific applications. Alternating Current is useful because of how easy it is to run through a transformer and boost the voltage ridiculously high in order to send it long distances. Direct Current, meanwhile, is more useful for communications and other lower voltage applications and is exclusively the domain of computers.

When we boost the voltage for transmission, we're using our friend Ohm's Law to reduce the amount of voltage lost during that transmission. Since we don't have stable super conductors at temperatures that make them useful (yet), we have to size wire based on the amount of amperage we plan to put through it. Because a transformer only changes the ratio of voltage to amperage (basically power in = power out), we can set the voltage as high as we want, which drops the number of amps, and because Voltage = Amps times Impedance, lowering amperage lowers the total voltage lost in the system. BUT! There is the issue that voltage that high does tend to require very high wires overhead to avoid arcing to the ground and all, so we step that voltage back down at a substation and then again when it reaches your home/business/factory.

DC is still incredibly useful however, since almost all computers and low voltage devices such as fire alarms, HVAC controls, communications, etc. use DC because the voltage remains stable, and that can be used to determine states. A state in this case is the condition, and the way it would work would be that a device (let's use fire alarm) is on a circuit and the monitor is sending a standard 24V. Suddenly, that voltage goes to zero! Depending on how sophisticated your system is, it might just sound the alarm or do some quick diagnostics and figure out which unit went down. Regardless, it has a reason to suddenly go "Oh no! Problem!" and things happen like alarms and whatnot.


Another area that DC has exclusivity is in batteries. While we use AC for general power, they can't charge batteries, which is a problem if you want battery backup of things like exit signs, emergency lights, etc., so we have to run the AC power through a step-down transformer, then through a rectifier to create pseudo-DC (it's close enough) and that can charge the batteries. When it's tine to use that power and if it needs to be AC again, we have to run it through an inverter and then a transformer again to step it up to something useful. Solar panels create power in DC, so to use their output you must run it through an inverter as well.

So it's less that Edison was wrong and more his system wasn't suited for most of our electrical needs, but DC is becoming more and more useful in our everyday lives. I doubt it'll ever supplant AC voltage because it's just too useful, but it's interesting that it is coming back in a big way.

[Cheekie]

I have one but I am not sure if this is even a good question,

This may be morbid, but do you need a grounding thing when you electricute someone? i.e. The electric chair.

Is any fluid charged when a current is entered it? Alternatively, is there any fluid that with not carry a current?

Can you answer about magnets? How does a Magnetizer Demagnetizer Box Screwdriver Magnetic Tool work?

[GloomCookie]

Wee morbid questions are best questions XD I can answer all but the last I'm not sure how those work.

So ok, yes, you always have a grounding wire. Voltage only works if it is relative to something else, otherwise the electricity has nowhere it wants to go. Electricity comes in from the utility and enters the electrical panel and is then sent either to other panels or what we call branch circuits (branches like a tree so they spread out and go all over). The voltage drives the electrons along and they go all the way down the wire, through the load (in the case of a person on the electric chair, they are the load) and then it comes back along the neutral. When it gets to the panel, it lands on the neutral bar, which then goes back to the main panel where there's a thing called a bonding jumper that goes from the neutral bar to the ground bar, and then goes out to the ground. Like, literally to the ground, NEC 250.52 (I think that's it in bed so can't check) calls for a firm bonding to three ground rods or a ground ring sized per NEC table 250.66. Since the voltage is relative to the ground, it's zero voltage when it actually reaches the ground.

Fluids are a bit outside my normal wheelhouse but I do remember there are times when you'd use fluids to alter electrical properties. Usually in things like water, it's not so much the water itself that's conductive but rather the stuff in it, like salt. When salt is dropped in water, it breaks up into ions of chlorine and sodium, which lets electrons flow much easier. Water is a dipole and in the presence of electrical fields (similar but not quite magnetic fields) it breaks down into hydrogen and oxygen, but this process is slow and energy intensive. But this is also why some capacitors have different fluids in them, since they can either help or hinder the flow of electrons. Usually you find these in situations where you want to adjust the capacitance which has various uses from how frequently they discharge to what frequencies they're good for. The best would be a pure vacuum but since those are difficult to make on Earth pure air works good to inhibit flow while chemicals like boron are used to increase capacitor values.

[Cheekie]

Did you know that you can get earthworms to come to the surface with electricity to the ground?

[Oniya]

Did you know that you can get earthworms to come to the surface with electricity to the ground?

Frankly, if my walls and floors started to get zappy with more than static, I'd leave my home, too.  (This, however, turns out particularly badly in the old horror movie 'Squirm'.)

[Flux]

Hey GloomCookie,

You still looking for questions?

Can you explain why in one building you might see big high bay lights but in other buildings you might see smaller 2x4 florescent fixtures used?

[GloomCookie]

That depends heavily on a whole host of factors.

Those big high bay lights are meant to throw a TON of light in a big area around it, so much so that if it were much closer to the ground the heat would make it uncomfortably warm. All lights produce waste heat, even LEDs, and while the efficiency of turning raw electrical power into light has gone way up, you still get heat as a byproduct. Plus, heat itself that you feel is thermal energy that is transmitted by photons, some of which produce visible light.

A good example might be when I work on a Planet Fitness. They have high bay lamps in the exercise floor, and smaller can lights in the lockers/showers. In the exercise floor with a really high ceiling, I can put about 40 high bay fixtures, while I have to put the same number of can lights in an area less than a quarter of that to produce comparable light levels at the floor. Granted, those high bay lights take more power overall, but the area they cover makes up for that.

The major cost benefit is a high bay is cheaper overall, but those lamps are expensive to replace. 2x4 fluorescent or LED retrofits are pretty cheap per lamp, while an LED replacement for a high bay could cost you a lot more, and when one of those things goes out, it creates a large dark area. Plus, since they're so high up in the air, it's a major operation to replace it, while if a single 2x4 fixture's lamp goes out, you have only a fractional loss of your overall light. They might order a pallet of fluorescent bulbs and once a year shut the facility down and just go around replacing lamps.

What it usually boils down to is owner preference in that case. They know which is going to be more economical on their end, as they might have a warehouse somewhere and every year order a thousand fluorescent or LED tubes from a manufacturer and stick them in this warehouse for future use, or they just order a ton of lamps all in one go. We just installed a few high bay fixtures in our garage, and we chose round LED over linears because they produced more light and we can replace them a lot easier than a linear. It's all about application.

[Flux]

Hey GloomCookie, That's awesome thanks for the answer!

Sorry if the question didn't really flex your brain in a way you were hoping.  Confession; I'm an electrician.  In my first post I had originally typed out a question for you, but when I re-read it I got in my head about it and felt guilty dropping a question that was obviously from someone trained in electrical of some sort. Sorry for not coming forward with that in the first post.

If you're still interested, I'd enjoy asking more questions to help find areas needing improvements?

So I'll just leave this here for you if you'd like it.  Can you explain why power transmission cables are such high voltages?

[Oniya]

So, here's one - I've got fluorescent fixtures in the place I'm in.  The tubes in one of them only light dimly - a bare glow at the ends of the tubes, even after buying new ones.  What causes this, and what options do I have to fix it?  (Hopefully cheaply - otherwise I'm passing it on to the next tenant to fight with the landlord over.)

[GloomCookie]

Sure thing. They're high voltage to avoid voltage drop.

I know that sounds incredibly circular so let me explain using some really simple math. Ohm's Law is Voltage = Current x Resistance. In the case of all wires, you have resistance in the wires since they're not perfect conductors, and usually it's based on Ohms/Length. We also have the equation Power = Voltage x Current.

So let's say I have a transmission line that's 50 miles long, and just for the sake of convenient numbers the total resistance in the wire is 10 Ohms, and I want to send 100 Watts down this power line. I can either send the power at 10 Volts or 100 Volts. Let's see what happens in both cases.

If we send 100 Watts at 10 Volts, we'll have 10 Amps of current going down the wire (100W = 10V * 10A). 10 Amps times 10 Ohms = 100 Volts. So by the time the power reaches the end of the wire, I've lost 100 Volts, which isn't good since I only started with 10 Volts, meaning I can't send any power down the wire.

If I instead start with 100 Volts, then I only have 1 Amp of power to get the same 100 Watts. 1 Amp * 10 Ohms = 10 Volts of drop, meaning from my starting point of 100 Volts, 90 Volts reaches the other end.

Voltage drop is a pretty big deal. The NEC tries to cap voltage drop at a maximum of 5% from the utility transformer to the furthest branch circuit device. I've written my own Excel calculator to carry numbers down, because there are so many factors that come into play. Those variables are:
Voltage (Plus if single or three phase)
Load (either in amps or volt-amps, this will take either)
Length of wire
Number of wires (sometimes they can be run in parallel)
Breaker size (15A, 20A, 25A, 30A, 35A, 40A, 45A, 50A, 60A, 70A, 80A, 90A, 100A, 125A, 150A, 175A, so on and so forth.. the calculator also flags if the total load exceeds 80% of the breaker rating or exceeds it entirely)
Conduit material (Steel, Aluminum, or PVC)
Wire material (Copper or Aluminum)
Ambient temperature
Number of other wires that might be in the conduit (not counting the number of wires of that particular circuit)
Power Factor (how efficient the device is)
How much we have left to play with (if I have already lost 3.6% getting to the serving panel, I only have 1.4% to use)

That calculator then has to run those calcs for every wire size until it gets a number below what I can use. For fun, here are the wire sizes it must calculate:
#12
#10
#8
#6
#4
#3
#2
#1
#1/0
#2/0
#3/0
#4/0
250kcmil
300kcmil
350kcmil
400kcmil
500kcmil
600kcmil
750kcmil
1000kcmil

And once it gets done with all that... you move on to the next.

There's a reason I wrote that calculator XD Considering a Planet Fitness or Joann's has like, 7 panels, each with up to 42 circuits each, that's a lot of calculations. When I did Krogers, we'd have like 15 or 20 panels. Madness I tell ya!

Speaking of Kroger we actually had to defend our use of transformers on that one. We used smaller distribution transformers across the store and pointed to the cost of wire to justify that even putting in a $5000 transformer saved them more in material costs than running everything from the back of the store like they'd been doing. We have similar considerations when we specify large equipment transformers because sometimes the cost of an individual transformer may offset the cost of running conduit and wire out to the equipment. So in addition to voltage drop being a major consideration we also have costs to figure out.

I might need to make a handy calculator for the cost of a transformer vs. feeders... *scoots off to do that*

So, here's one - I've got fluorescent fixtures in the place I'm in.  The tubes in one of them only light dimly - a bare glow at the ends of the tubes, even after buying new ones.  What causes this, and what options do I have to fix it?  (Hopefully cheaply - otherwise I'm passing it on to the next tenant to fight with the landlord over.)

Oh this is easy. Your ballasts are bad. I used to replace them when I was a teenager and they're not that expensive, you just need to find an equivalent. So on top or inside the fixture should be a long black box with wires running to it in various colors but usually black, white, red, and blue (your particular model may vary). The black is your hot, white your neutral, red your secondary hot and blue your secondary neutral. You'll need to order replacements and install them and it should be a fairly quick fix.

https://youtu.be/aWvREr_qJTM

[Oniya]

Oh this is easy. Your ballasts are bad. I used to replace them when I was a teenager and they're not that expensive, you just need to find an equivalent. So on top or inside the fixture should be a long black box with wires running to it in various colors but usually black, white, red, and blue (your particular model may vary). The black is your hot, white your neutral, red your secondary hot and blue your secondary neutral. You'll need to order replacements and install them and it should be a fairly quick fix.

https://youtu.be/aWvREr_qJTM

Quick follow-up - is this a 'things just wear out' problem or a 'something else caused this' problem?

[GloomCookie]

It's a 'things just wear out problem'. Ballasts are pretty reliable for a number of years but eventually they do get old and die. They average ~20 years or so but environmental factors can and do cause them to fail prematurely.

You might check, but that should fall under a Landlord problem since unless you're expected to maintain your apartment/flat in your lease agreement, the landlord should be responsible for replacing the ballast. I know some leases are stringent about bulbs but since this is the thing that powers the bulbs, it should be their problem.

If for whatever reason they come back and demand you fix it, totally demand they point out where it says that in your lease agreement. Some landlords might not even know what the hell you're talking about, but unless you want me calling on your behalf which would get awkward in a hurry, just send them that video.

[Inkidu]

Fun one: What is Unobtanium?

[GloomCookie]

Unobtainium is a material that's very rare and hard to come by, similar to handwavium, phlebotinum, eludium, wiahalloy, impossibrium, raritanium, hardtofindium, etc. It's basically a very expensive material that you wish you had a lot of but is stupid expensive to justify, like a free lunch that doesn't consist of a bologna sandwich and a package of chips on Engineer day, or a gas station burrito that tastes good and doesn't give you the runs.

If you're talking about Unobtanium the material from the movie Avatar, it's basically a room temperature stable super conductor. Super conductors are a type of material that can transmit electricity with little to no inherent resistance, meaning that in the example I gave earlier about voltage drop and transmission lines, you have the same voltage you started with and don't need a step up and step down transformer, you can send power directly where it's needed. This is useful because the further something is from a power plant, the more inherent losses are generated by the system until it's no longer worth the effort. It's called Unobtanium because the term was coined in the 1950's to describe materials that are good for aerospace but are too expensive to reasonably obtain.

Good example would be the SR-71 Blackbird, whose flight characteristics made using aluminum impractical because the aluminum couldn't maintain its structure and would burn up at high temperature, while steel was too heavy to do the job. Instead, they had to turn to titanium, which was capable of doing the job but had another problem: the only country in the world capable of producing titanium in the quantities they needed was the Soviet Union, the very nation they intended to spy on. So the CIA created a number of shell companies and bought the titanium, had it shipped to the US, and they used it to create the SR-71.

In the electrical trade, there are two very good metals even better at conducting electricity but their price makes them Unobtanium: gold and silver. Gold is sometimes used to plate some electronics and such, but rarely. It's not uncommon, however, to see either copper-coated aluminum or just pure aluminum conductors in certain applications, mainly transmission lines and large feeders. Some jurisdictions don't allow aluminum feeders under a certain size, mainly because for a long time electricians were using #14 AWG aluminum instead of copper to power receptacles and lights. The problem is that, as a general rule of thumb, aluminum needs to be two wire sizes larger, and the NEC only allows aluminum conductors starting at #6 AWG for 50A circuits and above.

The reason for this is because while aluminum and copper wire can both handle up to 600 Volts, the diameter of the wire is what determines ampacity. Copper is allowed to go as small as #14 AWG for 15A circuits, #12 AWG for 20A, #10 AWG for 30A, so on and so forth, but for those small sizes it's against code to use aluminum. If you used #14 AWG aluminum on a 15A breaker, the wire would overheat and catch fire before the breaker's thermal element has time to trip, which causes a fire. But, just because it's against code doesn't mean someone somewhere isn't installing it and hoping the inspector (if there even is one) doesn't catch it.

[Flux]

Wow, that was a great explanation of voltage drop and power transmission thanks!  You really know your stuff well.  How did you make out with your calculator? Get one figured out?
I got another one for you, what is the purpose of an interposing relay?

[GloomCookie]

Oh yeah. We're on version 2.4 and it's handy as hell. The older one took hours to do what now just takes minutes, and before that when everything was done by hand you had a literal slide calculator. I'll see if I can find the one I have at work when I go in on Monday.

As far as Interposing Relays go, I'd never heard the term but I know what they are now. So their job is to take low voltage DC signals like from a computer or controller and use it to switch on and off devices at line voltage (120V or so). Most computers are built on either 6V, 12V, or 24V (there's a few in between but those are the most common), and when you have a controller it can only output a low voltage signal. But, if you try and plug in a 120V device into that controller, the controller doesn't put out enough power to do anything, and if you try plugging in a 120V source into the controller, you get a lot of blue smoke and angry yelling from your boss.

The thing is basically a relay or contactor, depending on your terminology. We use these things all the time in projects and you might have heard them called NO (Normally Open) or NC (Normally Closed) contactors. We use them a lot with timeclocks for lighting controls so that lights turn on and off at given times, such as 6:30am before the employees arrive. No one has to touch a thing, the lights just turn on and everyone's able to start working.

The source I found for what they are mentions PLC, which is a Programmable Logic Control, and I've actually had my hands on some of these things. They use what's called Ladder Logic to run multiple simple logical commands nearly simultaneously, and replace having to hard wire logic gates and relays. Instead, you can have inputs and outputs to do different things, and the controller handles all the logic internally. They're mostly used on industrial machines and can be simple things like having a contact that if it's open, you can't start the machine because a door is open that would be dangerous, so you must shut the door so you can't stick your hand in and get pulled into the machine.

I haven't messed with PLC in years but if you wanna know more, there's actually a 'game' on steam that's a simulator called Automation that lets you simulate programming machines with PLCs.

https://store.steampowered.com/app/1698690/Automation/

[Inkidu]

Unobtainium is a material that's very rare and hard to come by, similar to handwavium, phlebotinum, eludium, wiahalloy, impossibrium, raritanium, hardtofindium, etc. It's basically a very expensive material that you wish you had a lot of but is stupid expensive to justify, like a free lunch that doesn't consist of a bologna sandwich and a package of chips on Engineer day, or a gas station burrito that tastes good and doesn't give you the runs.

If you're talking about Unobtanium the material from the movie Avatar, it's basically a room temperature stable super conductor. Super conductors are a type of material that can transmit electricity with little to no inherent resistance, meaning that in the example I gave earlier about voltage drop and transmission lines, you have the same voltage you started with and don't need a step up and step down transformer, you can send power directly where it's needed. This is useful because the further something is from a power plant, the more inherent losses are generated by the system until it's no longer worth the effort. It's called Unobtanium because the term was coined in the 1950's to describe materials that are good for aerospace but are too expensive to reasonably obtain.

Good example would be the SR-71 Blackbird, whose flight characteristics made using aluminum impractical because the aluminum couldn't maintain its structure and would burn up at high temperature, while steel was too heavy to do the job. Instead, they had to turn to titanium, which was capable of doing the job but had another problem: the only country in the world capable of producing titanium in the quantities they needed was the Soviet Union, the very nation they intended to spy on. So the CIA created a number of shell companies and bought the titanium, had it shipped to the US, and they used it to create the SR-71.

In the electrical trade, there are two very good metals even better at conducting electricity but their price makes them Unobtanium: gold and silver. Gold is sometimes used to plate some electronics and such, but rarely. It's not uncommon, however, to see either copper-coated aluminum or just pure aluminum conductors in certain applications, mainly transmission lines and large feeders. Some jurisdictions don't allow aluminum feeders under a certain size, mainly because for a long time electricians were using #14 AWG aluminum instead of copper to power receptacles and lights. The problem is that, as a general rule of thumb, aluminum needs to be two wire sizes larger, and the NEC only allows aluminum conductors starting at #6 AWG for 50A circuits and above.

The reason for this is because while aluminum and copper wire can both handle up to 600 Volts, the diameter of the wire is what determines ampacity. Copper is allowed to go as small as #14 AWG for 15A circuits, #12 AWG for 20A, #10 AWG for 30A, so on and so forth, but for those small sizes it's against code to use aluminum. If you used #14 AWG aluminum on a 15A breaker, the wire would overheat and catch fire before the breaker's thermal element has time to trip, which causes a fire. But, just because it's against code doesn't mean someone somewhere isn't installing it and hoping the inspector (if there even is one) doesn't catch it.

I was looking for the room-temperature superconductor and why that was such a big deal for material, electrical, and computational sciences.

The term pre-dates Avatar by decades and is used to specifically refer to a room-temperature stable superconductor. The fact that Avatar unironically uses that term is a question I'll save for when someone wants to run an AMA on writing techniques. 

[TheGlyphstone]

The Core did it first and its not even a superconductor there, just some sort of impossibly heat resistant alloy.

[Azy]

Okay, here's a question.  The light in my back storage room, and the lamp in the nearby hallway have a tendency to flicker a lot.  This has gone on the entire three years that I've been here, so the bulbs aren't going bad.  What could cause that, and should I worry? 

[GloomCookie]

Hmm.

There's a whole host of reasons as to why. When they flicker, is it because something else is on nearby? Is it cold? Do you know of anything else on that circuit?

Again, the reasons could be numerous, so without more context, I just don't know what to tell you :(

[Azy]

It flickers at least once or twice every day that it gets left on for any period of time.  It does seem to be a little worse when the living room ceiling fan is running.  I think they're connected somehow.  There's the back room, a little hallway that goes to the bathroom and bedroom, and then the living room.  When the outlet my fridge is plugged into in the back room stopped working, so did the ceiling fan, but everything else in the living room was fine.  My mom had to find the wiring map for her fiance to fix the issue. 

[GloomCookie]

It flickers at least once or twice every day that it gets left on for any period of time.  It does seem to be a little worse when the living room ceiling fan is running.  I think they're connected somehow.  There's the back room, a little hallway that goes to the bathroom and bedroom, and then the living room.  When the outlet my fridge is plugged into in the back room stopped working, so did the ceiling fan, but everything else in the living room was fine.  My mom had to find the wiring map for her fiance to fix the issue.

Hmm. Is the ceiling fan on a dimmer switch? If so, that might explain it. Even if they're not on the same switch, the changes in voltage as the ceiling fan is dimmed could bleed over into the light itself. It sounds almost like whoever wired the house might have also put the refrigerator on the same circuit, so you have two motors that are going to screw around with voltage, affecting the light's performance. Only real way to fix it then would be to rewire the light to either share the circuit with a nearby light or give it a dedicated circuit to the panel.

[Numerion]

So question: lately whenever I hear my fridge start its system/fan and stop, I can hear a bleep in my speakers. I assume the speakers are reacting to a spike of some kind on the wire, but it didn't happen before. The fridge and the speaker are on completely different circuits as well.

Any hints what may be happening?

[GloomCookie]

So question: lately whenever I hear my fridge start its system/fan and stop, I can hear a bleep in my speakers. I assume the speakers are reacting to a spike of some kind on the wire, but it didn't happen before. The fridge and the speaker are on completely different circuits as well.

Any hints what may be happening?

Probably the motor in the compressor kicking on producing the magnetic field, and the sudden magnetic force is enough to make the pop.

Unless they're 'soft start' motors, most motors are basically connected to the source and are, for a brief and glorious moment, a short circuit. The reason this doesn't remain the case is that the tight windings of the wire inside the case start to produce a magnetic field, which itself starts to interfere with other electrons and it starts to generate its own impedance. Since your speakers are themselves powered in a similar fashion (just using the magnetic field to move the steady state magnet back and forth) then any nearby high magnetic field like that will cause interference. Since this magnetic field didn't exist before the motor kicked on, the speakers couldn't account for it, and that pop is just the magnet suddenly moving unexpectedly.

If you want to avoid it, move the two away from each other. There's really no other way without getting into weird stuff like Faraday cages and the like.

[Oniya]

If you want to avoid it, move the two away from each other. There's really no other way without getting into weird stuff like Faraday cages and the like.

Speaking of getting into Faraday cages, have you ever seen the lightning show from the Boston Museum of Science?  (Terrible segue, I know.)

https://www.youtube.com/watch?v=U4WZPjwNYN0

Those two massive spheres on columns in center stage are Tesla Coils.

[Numerion]

Probably the motor in the compressor kicking on producing the magnetic field, and the sudden magnetic force is enough to make the pop.

Unless they're 'soft start' motors, most motors are basically connected to the source and are, for a brief and glorious moment, a short circuit. The reason this doesn't remain the case is that the tight windings of the wire inside the case start to produce a magnetic field, which itself starts to interfere with other electrons and it starts to generate its own impedance. Since your speakers are themselves powered in a similar fashion (just using the magnetic field to move the steady state magnet back and forth) then any nearby high magnetic field like that will cause interference. Since this magnetic field didn't exist before the motor kicked on, the speakers couldn't account for it, and that pop is just the magnet suddenly moving unexpectedly.

If you want to avoid it, move the two away from each other. There's really no other way without getting into weird stuff like Faraday cages and the like.

oh it didn't even occur to me it could be for magnetic field regions!

And it makes sense, I had tons of interference from wires between my setup and the kitchen and couldn't link up stuff so I redid some of the wiring and after that the speakers started responding to the fridge!

I didn't connect the two, thanks :D

[TheGlyphstone]

Speaking of getting into Faraday cages, have you ever seen the lightning show from the Boston Museum of Science?  (Terrible segue, I know.)

Those two massive spheres on columns in center stage are Tesla Coils.

Did someone say Tesla Coils?  ;D



TWO THOUSAND VOLTS, COMING UP.

[GloomCookie]

So just an update for everyone, I passed my PE exam in December 2022 and was licensed in Arkansas as my first state. Yesterday I got a notice that I've received my license in MA, so I'm now registered as an engineer in Arkansas, Maryland, Tennessee, Nevada, Texas, and Massachusetts.

So many bad decisions have been made XD

[Silvered Sutures]

How do you convert from hydro to nuclear?

[MightyMaiden]

On a 20A single phase circuit, how many LED fixtures could you have connected if the typical draw/standby was 2A/0.07A @ 100v with an inrush current of 55A 120v (First half cycle)