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Q. We moved into our home three months ago in Florida. Surprisingly, we get power surges a few times per week, sometimes in the middle of the night. We have surge protectors on the appliances, computers and TV's. I am wondering if a protector on the electric panel itself installed by an electrician would be a big help or not really?A. I guess I might call those brief power outages. I would normally infer a temporary voltage increase from the phrase "power surge." Chances are that some cutoff in the power company's distribution system is cutting out and automatically resetting itself. You could call your power company to see if they are having problems or if they recorded any events in their system at the times you noticed problem. You could also ask your neighbors if they are experiencing similar occurrences. A whole-house surge suppressor (TVSS) on your main power supply is a good idea in areas with frequent incidents on the power supply. They can usually be installed for a few hundred dollars. They don't replace the point-of-use surge suppressors, but augment them well.
Q. Our home is approximately 15 years old and is fed from overhead power lines that have a large transformer that is very old and rusty and provides power to homes in our area. Just recently over the last few months, we noticed the lights in the house would occasionally flicker and dim but we could not figure what could be causing the problem. Our next-door neighbor had recently had a central Air Conditioner unit installed, and yesterday evening while sitting on our patio, we noticed that when their air conditioner compressor starts up, the lights flicker and dim in our home. Is this possible? If so, what do we do to correct it?
A. Yes it's possible. Call the power company. It may be that the homes in the neighborhood receive power from this same pole and same transformer, which makes transformer not able to handle the start up surge from these units. The transformer will need to be replaced.
Q. Could you please explain (in Layman's terms) the difference between voltage and current, and why each is important in their own rights?
A. This is a very general way to think of it: Think of it in plumbing terms. Pressure = voltage, and volume = current. Example: A small pipe with a large pressure would be like a higher voltage with a low current flow, and so on.
The plug in your wall has 120 volts of electromotive force sitting there. No current flows because there is no place for it to go. Plug something in and the amps start flowing. Just how many amps flow is determined by the force, in this case 120 volts, and by the RESISTANCE of what you plug in. A 100-watt bulb has a lower resistance than a 60-watt so MORE current will flow.
Q. How does one measure voltage? Does voltage have anything to do with the wave pattern of the electricity, or is that strictly a function of hertz? If you could see electricity, would more volts make the energy flow any faster? I suppose the question is: how can you tangibly describe volts? I understand how it plays a role in the equation, but tangibly what does it mean? I suppose a roundabout way to answer that question is to explain how voltage can be raised and lowered by the power company. How is the power company able to adjust voltage supplied to their customers? I'm sure they have some special dial, but how does that dial affect the electricity's voltage?
A. Both current and voltage would look like a sine wave if viewed on an oscilloscope. Both are 60 hertz (although not necessarily exactly in phase with each other). The reason voltages are stepped up during transmission is to reduce current, and thus save resistance losses in the line. The reason that they are stepped down before it gets to your home is safety for you.
The power grid is all alternating current (AC) and also alternating voltage of course, because AC voltage is much easier to step up and down than direct current (DC) is. This is the source of the famous Westinghouse/Edison debate of a century ago. As you know, AC (Westinghouse) won the battle over DC (Edison) because of its ability to be easily voltage stepped.
The rate of energy flow is called "power" and is measured in watts. Power is a function of both voltage and current. If you use a transformer to step up the voltage, the current will drop by a corresponding amount. The power is the same. So the answer to your question is generally "no" if you're talking about power distribution. But looked at another way, the answer could be "yes." A given light bulb will use more power (i.e., energy will flow faster) if you give it more voltage (because it will also use more current). By the way, electricity traveling through copper wires travels considerably more slowly than the speed of light.
Q. Currently, I am remodeling a recently purchased condo. I have to replace the old rusted water heater and I am considering purchasing a tankless system because I cannot find anything that will fit underneath my cabinets that is bigger than 28 gallons. The tankless water heaters require 220 Volt - 54 Amp. Can I tell by looking at my panel whether or not my place can handle this and if so, what type of setup is required?
A. First, you need to know the size of your current service. It should be a number imprinted on the handle of the main breaker in your panel. I would guess it's 60, 100, or 150A. If you have fuses instead of breakers, then your service is certainly small.
Next, you need to do a "demand load calculation" for your residence to determine your current electrical requirements. Google for that phrase, and you will find a tutorial on how to perform this calculation.
Finally, you need to add 54A@240V (12,960W) to your present requirements and see if it's less than your service size. If so, then you can add the tankless heater without a service upgrade. Otherwise, you would need to upgrade your service and main breaker panel to handle the additional power.
For most people, an electric tankless water heater is not usually a good choice. It makes sense only if the family size is quite small, and the electrical service has lots of extra capacity in both power and space, which is usually only true in new homes. Even then, the installation cost can be quite high unless the electrical panel is near the installation site.
Q. With summer here and lightning being an issue, I was wondering - will a power strip that is turned off protect the appliances plugged into it from lighting strikes and power surges?
A. 1) Electricity does not "take the path of least resistance." It takes all paths in inverse proportion to the resistance. If you have two paths, one with twice the resistance of the other, then the higher resistance path would see half the current of the other.
2) With power line surges, the voltages that we are talking about are low enough that the switch contacts represent an "open circuit," or infinite resistance, so no current will flow.
3) With lightning, all bets are off. The voltages available with a lightning strike are enough to arc over a tiny little switch, and cause the air itself to be a conductor. The speed at which the current level changes makes this a situation where even figuring out the resistance of the path is next to impossible.
4) With a computer, you have to consider both the computer itself, the communications lines and anything else connected to it. It is entirely possible for a lightning induced current to enter through the power supply ground pin, and travel out on a communications line, frying everything in between. A UPS won't help with this since the grounds are simply connected. Instead you need to make sure that all lines entering the computer have surge suppression between them, and that every service in your home has proper ground bonding.
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