I spend way too much time on RV forums, particularly RV.net and have begun to notice a subject which brings out opinions in a lot of folks on the forum is electricity, and I am wondering why that is! Electricity has been around for longer than most if not all of us have been alive. We use it every day, in so many ways, we can’t begin to describe them. There are large sections of libraries devoted to books on electricity. Many schools teach courses on electricity and if you do a search on the internet you can find a huge selection of websites that will tell you just about anything you want or need to know about electricity. Ok, so why are there so many varying opinions and so much misguided information circulating about how electricity works, and how we should properly use electricity?
I suspect part of the problem may be that we all, or at least most of us, believe we know “something” about electricity, and want to share that knowledge with others. The danger of this is that a lot of misinformation, some of it dangerous is passed around, oft times presented as true and correct. A rookie, or newbie may read this information and accept it as accurate, and use this information with potentially dangerous consequences.
What got me started on this rant was a recent thread on RV.net about running an RV air conditioner on a 20 amp residential outlet, a very doable procedure. In the content of this thread one poster referenced a website as “gospel”, and quoted from that website, in part, as follows:
“Let’s say for example you plug into a 15 Amp outlet and you are using a small appliance that is drawing 5 Amps, that leaves you with 10 Amps.”
Unfortunately this is a gross simplification, and in fact it is technically inaccurate. However, unless a reader of the post, or viewer of the referenced website understands how 20 amp circuit breakers work, they may act on this information to their detriment.
In the next few posts, we will discuss some of the things we should consider when we look at safely loading an electrical circuit. By being aware of these points we can all be safer when using electricity in our homes, rolling or stationary
Larry
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larrycad
G.M. said, “I think a fuse has a faster release time than a ckt breaker. ”
G.M. sorry to disagree with you again, but it is inaccurate generalizations like this that tend to cause confusion. Someone reads your comment and assumes you know what you are talking about because you are an electrician. Therefore they remember what you say, and even quote it to their friends with “authority” and a falsehood is created.
As a state licensed electrical contractor, owner of an electrical contracting company, and an electrical engineer, I spend a lot of time working with my customers on various items such as arc flash analysis, and current limiting coordination. I can assure you that to say what you said is flat out wrong. There are fuses that will clear a fault more quickly than circuit breakers, BUT, there are circuit breakers that will do the same compared to fuses. It is not a simple, straight forward subject. If you are really interested in learning about time/current curves for fuses and circuit breakers, you may want to google the subject and spend a few hours reading up on it. It is interesting reading and it is also very useful when correctly explaining over current protection.
I do agree with you that many people don’t have a true understanding of the awesome power of electricity. I teach seminars to groups of industrial electricians and one of the main subjects I cover is electrical safety and the many aspects of that subject.
On this forum, I try to offer advice for working on electrical systems, but I also try to keep in mind that many of the folks reading these posts are not familiar with some of the dangers associated with working on electrical systems.
G.M.
Granted, a bad connection can heat up and cause damage, but circuit breakers do a wonderful job of protecting electrical circuits. I strongly disagree with your comparison of circuit breakers with fuses.
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Not really. I think a fuse has a faster release time than a ckt breaker. ( By the time the element in the Ckt breaker heats up to cause it to release..) the fues has already opened up… Check out the manufactures specs on them. Properly rated fuses are still the perfered method of protection. Most of the stuff that is on ckt breakers usually goes toast just before the breaker opens. About the only advantage to a Ckt breaker is that you can go back and re-set it without having to replace it. Some new solid state Ckt breakers actually sense the current draw and fire a device to open the circuit. (100 times quicker than either a fuse or common breaker can) Is this good… well not really as it also senses the spikes at the on/off or coming into the unit. Tripping it off then back on kinda thing. Makes watching the TV a little tough.. especally during the soaps when the wifiee was trying to keep up…
Actually the collider is causing more confusion in the E mo world. Quantum physics now shows that what we thought is not necessarly true. As the atoms turn… kinda thing.
Larry…
some people look at and relate power as a rotating mass of equipment that has heat and noise. Most people look at two wires and have no idea of what damage they can do or how it happens as they see just two (no heat, no movement) items. We all know they have that snake lurking in the wires that will reach out and light you up. Electronics and elect are areas that one hasn’t a clue as to how it works and so when problems come up.. seek professional help from ones that do. The concept of electrical load is imaginative at best untill the smoke starts to escape from the device or wireing…. and we all know that once the smoke escapes the item is dead and needs replacement.
By the way … most current is converted to magnetics and then to mechanical and back again in todays world.
Telling a woman that she can’t use the hair dryer, curling thingiee, bathroom elect heater, electric skillet cooking and have the TV on all at the same time overloads the RV wireing.. her first look after you say that …gives you a clue as to if your speaking greek or not. Concept be damm… you can expect her to say.. well I can’t do without any of these things .. so you take care of it.. meaning… get with the program dude and get us some more power else I am leaving… porter get my bags…
That being said… or infered… harry heads off to the hardware store to get a bigger plug and wire… not knowing anything about rocket science.
Learning how to handle electricty is not something you can explane in 10 words or less. That is why they have tech people go to school for a couple of years I think. We all know that a RV nut is a lot smarter than those people and can probably comprehend it in say… how long?
When you first look at it.. most RV’s appear pretty simpleistic but in reality can become very system complex when examined more closely.
It might be a good idea to have a traveling seminar on just the electrical issues of a RV so that othes can attend and learn more. (show and tell on how to use a voltmeter too)
larrycad
tropical, you certainly have a way with words. Maybe now that they have the “super collider” working in Switzerland, they will be able to prove which way electrons actually flow. Maybe………….
Larry
tropical36
What causes all this sudden interest of electrical topics, is the fact that most of the world doesn’t have a clue about the mathematical theory of electron flow, which is still to this day an unproven fact, ( I think I can prove that it’s unproven) even though it works quite well.
A good reason for such a lack of knowledge among the masses when it comes to electricity, is that it’s complicated and not like a lot of other things that it’s compared too. So, as a result, most don’t qualify or bother to try until they find out how much it’s going to cost to fix it or maybe not fix it, because their choice of professional tech. help was inadequate. Then all at once, they’re eager to learn something that usually takes years of formal education and proper training.
larrycad
Thomas, you are correct regarding the 1500 watt heater. Actually, 1500 watts divided by 120 volts = 12.5 amps, and 12.5 amps is 83.3% of a 15 amp circuit. Sooooo, if the line voltage is 120 volts, the 1500 watt heater will be exceeding the 80% limit.
I also agree that the “stab” connections on duplex outlets are junk!! Unfortunately underwriter lab has seen fit to certify them and the electrical industry uses them, as does the RV industry. I have personally changed several of them in friends RVs where the connection has been burnt or arced. It is scary!
I don’t agree with your statement about trusting circuit breakers. Granted, a bad connection can heat up and cause damage, but circuit breakers do a wonderful job of protecting electrical circuits. I strongly disagree with your comparison of circuit breakers with fuses. Fuses also have a time/current curve, just like circuit breakers. These curves vary with the type of fuse and the type of circuit breaker. When used properly, both provide excellent over current, and short circuit protection, assuming the installer has wired the circuit properly.
Larry
Thomas Becher
National Electrical Code says that a curcuit may be loaded to 80%. So an electric heater of 1500 watts is fully loading a 15 amp curcuit. Doesn’t let a room for something else.Don’t trust a curcuit breaker to protect your wiring, as a bad connection may heat and start a fire and that heat won’t be seen by the breaker. It will think of it as a load and just do what it’s supposed to do, provide juice. Also breakers are rated to provide power as much as 175% for three hours. I always liked fuses. The outlets that are provided in rv’s just pinch together and the brass part of it stabs into or around the wire. About the poorest connection one could have. As an electrican I made my living going to houses replacing wiring and outlets for people that bought theoutlets that just pushed the wire in. I always called those people screwdriver impaired. A toaster, coffee maker, a converter and maybe the tv will just about load your 30 amp line to its 80%
larrycad
G.M., I remember when someone explained to me what a multimeter was for and I am glad they did. Few of us are born knowing everything and have to experience things in order to learn about them. Like Friedrich Nietzsche said, “That which does not kill us makes us stronger.”
PapPappy, I agree with most of what you said. The purpose for writing this and subsequent posts is to try to give electrical newbies some knowledge on which to base their decisions.
PapPappy
I agree that people may take what they read as gospel…and that we (the brain trust that thinks we know it all!) should stick to what we are sure of. Trouble is, many people are running their A/C units off a 15 A oulet…and it’s working. So, they assume that they know their stuff, and give out the advice in kind of a ” this is what worked for me” response.
Trouble is, they may very well come home tomorrow to find that their A/C has burned out due to low voltage, or that their house has burned to the ground due to the extreme heat that was generated by the wires trying to draw 20 amps through a 15 A circuit.
Breakers will eventually trip, but they usually only trip for a short, or high enough temps….and sometimes, that is too late, or the A/C unit is already toast!
Now, it may also be that the particular A/C unit that is being talked about, is a low wattage unit…plenty of people have little window units that plug into 15A circuits, right?
Yes, we need to be smarter in our advice, but if you read that entire thread, you will see that the lion’s share of advice is right on, and if the “newbie” doesn’t listen to the majority…and double check to be sure…well, then they sort of deserve what they get!
G.M.
Oh.. ya …
never play with anything you don’t understand…. seek a professional in that area. If the advise is free.. consider what your getting.
Playing with electrons… can kill you if done wrong. A lot of people don’t see the potential that can happen in wires. (look harmless because they don’t see anything moving… yet) Electricity is one of those forms of power that can be transformed into so many things. What would we do without it?
When you have to explane to the reader what a voltmeter is…and how to use it… give up on trying to get ’em to understand what a ground fault does… just point ’em in the right direction instead…
G.M.
No there are other areas that have lots of discussions…
trailer vs MH
Heaters
diesel vs gas
etc…
.. most need to remember that this is for entertainment and not a blue print on how to… Some suggestions are good others.. well… let the reader do the research.
most are trying to be helpful.
Merry Christmas