0
Electrical Wiring
Ask questions here about proper wiring and electrical installation here.
4,935 Questions
Hard wiring something is when you terminate the device or equipment directly with the cable/wires that are coming from the panel. Say for example: You have a 40' length of 10-3 M.C. cable (or similar) coming from your panel to feed power to the oven. In the case that the oven needs to be hard wired , there will be a junction box in the back , bottom, portion of the oven or an insulated cord with uncapped wires hanging out in which (either way) you need to splice the 10-3 cable to the wire ends of the oven inside that junction box (or the junction box that is installed in the wall). If the oven didn't need to be hard wired than you would normally install a 30-60 amp receptacle/outlet in a 4x4 box in the wall and you would terminate the 10-3 cable to it and the oven would come with a cord and plug that you would just plug into the wall.
So, an easy way to think of it is: If the equipment needs to be hard wired than it will not have a plug on the end of the cord/cable.
And if it doesn't need to be hard wired than you will just plug it into an outlet.
4.13566 x 10-15 times 2x10 Hz?
This seems like a question from an electrical course, and is probably best answered by your course materials. It's your test question, not ours, and there won't always be someone to ask the answer of. Earn your diploma.
What is the amplitude if y sin equals 20?
This seems like a question from an electrical course, and is probably best answered by your course materials. It's your test question, not ours, and there won't always be someone to ask the answer of. Earn your diploma.
GFCI circuitry checks for what?
Current Imbalance: GFCIs continuously monitor the current flowing in the "hot" (live) wire and compare it to the current returning in the "neutral" wire. If there is a difference of as little as 4-6 milliamperes (mA) between these currents, indicating that some current is not returning through the normal circuit path, the GFCI will trip and disconnect the power.
Leakage to Ground: GFCIs are designed to detect any unintended flow of electricity to ground, which could be potentially hazardous. This can occur when there's a fault in an electrical device, damaged wiring, or when someone comes into contact with a live wire or conducts electricity to the ground.
Rapid Response: GFCIs are engineered to respond quickly, typically tripping within milliseconds when they detect a ground fault. This rapid response helps prevent electric shocks and electrical fires.
How do I Convert hvac seer to tonnage?
Determine the SEER rating of the HVAC system. The SEER rating is usually provided by the manufacturer and is a measure of the system's energy efficiency.
Find the total cooling capacity of the HVAC system in BTUs (British Thermal Units). This information is also typically provided by the manufacturer and can be found in the system's specifications.
Plug the SEER rating and the total cooling capacity in BTUs into the formula:
Tonnage = (Total Cooling Capacity in BTUs) / (SEER)
For example, if you have an HVAC system with a SEER rating of 16 and a total cooling capacity of 48,000 BTUs:
Tonnage = 48,000 BTUs / 16 SEER
Tonnage = 3 tons
Paper is highly flammable. it is obvious this would constitute a real and risky fire hazard. Perhaps you are thinking of machines that make up the metallic plates, which could use ( fire-forming) techniques. I am familiar with printing machinery to some degree and this one is new on me, adding heat and flames could not serve as a coolant. it is like the classic malaprop with airplanes- Diving to gain altitude! Diving to gain airspeed ( from gravity fall, of course) sure, but not altitude.
Bose Wave 110v to 220v converter?
The modifications fall into 4 categories. You may choose to make any or all of these modifications to suit your own needs.
1. Conversion of input voltage to receive 220-240VAC, instead of 110-120VAC
2. Conversion of Tuner - FM 50kHz spacing; AM 9kHz spacing
3. Conversion of de-emphasis from 75uS ( USA) to 50uS (EU)
4. Upgrade of the signal path capacitors.
It depends on how the wires are hooked up.
In general, the accepted practice is to use the green/yellow wire for ground. The blue wire is neutral. The brown wire is hot.
But saying this does not guarantee that the previous wire monkey did it right, especially if they followed the advice left here earlier... Click on the View Discussion button below this answer to see the first answer that was given to this question! So make sure you test your wires before using them to power a new circuit.
Cheap circuit testers are available at any local hardware store for just a few dollars. Remember that a light bulb isn't a tester - it will still light up if the wires are crossed.
This could mean that your light FIXTURE is HOT - potentially killing you when you go to change it. Even switching off the lights will not remedy the situation, since you're breaking the circuit to GROUND. That means you have a floating Live wire in the fixture, "waiting" for you to touch it and complete the circuit to Ground.
So, the moral is: DO NOT rely on colour-coding. Test your wires with the right equipment.
<><><>
Which leads to the follow-up moral: Make sure you get your work inspected or have it done by a qualified and licensed electrician.
NOTE: the above "accepted color coding" where BLUE is the neutral is generally in EUROPE and countries other than the USA. IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.If you do this work yourself, always turn off the power
at the breaker box/fuse panel BEFORE you attempt to do any work AND
always use an electrician's test meter having metal-tipped probes
(not a simple proximity voltage indicator)
to insure the circuit is, in fact, de-energized.
Why does 277 volts leg to legs waves do not read 554 volts?
The reason 277v leg to leg does not measure 554 volts is each phase of the system is 120 degrees out of phase with each other and there fore will not read 554v leg to leg but 480v lag to leg. If you take 277 times the square root of 3 it will equal 480. The meters measure Root Mean Square or rms voltages and are designed to take this into their readings.
Why does my outdoor power outlet not work?
There are several possible causes for an electric outlet not working:
- The outlet has gone bad such as internal contacts corroded or bent so they don't make a connection.
- The wire on the outlet is not connect or loose, not connected properly
- There is a break in the wire somewhere
- No power going to the outlet from the source, which could also be caused by a bad fuse
What mineral material is used as an insulator in electrical equipment?
Magnesium oxide is used in heating elements to isolate the inside heating wire from the elements outside sheath. This same material is used in Pyrotenax mineral insulated cables as an insulation medium.
Who invented the electric refrigerator?
The first known artificial refrigeration was demonstrated by William Cullen at the University of Glasgow in 1748. See link below for further information regarding the history of refrigeration.
How does different types of soil affect the type of electrical systems?
The only thing I can think of to such a vague question is; the grounding rods would have to be buried deeper in sandy, or marshy soil. Is this what you're after, or do you mean the construction and location of a powerplant? Different types soil have different electrical resistance properties. The higher the resistance in the soil the greater effect on the systems ability to establish a ground. A ground is used for multiple reasons, one being the return path for a 120volt system the other being a fault path for all systems. The lower the resistance at ground the quicker a fault will reach maximum current and opening of the protective device (less chance for fire to result). When the resistance of the soil is above a certain level measured with a ground resistance tester, normal excepted practices are no longer useful. There are many different methods some chemically applied some mechanically applied that can be utilized to reduce the resistance, the most suitable method is generally selected based on past experience and/or exceptability by the engineer responsible for the project. There are many things that affect the ability of soil to conduct electricity, as well as disapate it. Not only at the time of the test, but permanently. Without this ground and/or return path an electrical system becomes unsafe, unpredictable, and in most cases damaging to the 120v equipment that is connected to it.
Why are some house currents 130 volts instead of 120 volts?
It depends on the local utility power company and the the neighborhood transformer taps used. It also depends on how far away the transformer is from the house. There is a voltage drop depending on the size and length of wire. It sometimes is 120v, 125v, 130v or anywhere in between. It doesn't make much difference.
Is a 10 ampere fuse suitable for 240 volt?
Yes a 10 amp fuse can be used to protect a 240 volt circuit. The amperage rating of a fuse is based on the given amperage load of the circuit. The voltage rating on a fuse must match or be higher than the voltage that is applied to the fuse. In other words you can not use a 240 volt fuse on a 277, 347, 480 or 600 volt circuit but it can be used on a 120 volt, Manufactures of switching equipment today make it impossible to interchange different voltage fuses to be installed in higher voltage switches.
On the breaker panel the 3rd wire - colored green or just bare - is the Ground wire. It is there to protect circuits - different to the one you are looking at - which need to have a ground wire as well as a neutral. On such circuits, in case of a fault condition in the appliances connected to them, a short circuit is sent to ground so that the circuit breakers on the hot wires should then trip to break the power supply to such circuits and stop a house fire or someone getting killed by electricity.
This is not a full answer to your question. You still have to think about which types of appliances - having plugs with only 2 prongs on their flexible cords - are still quite safe to use and which types are definitely not safe to use with that type of socket outlet - and in that situation, what should be done to make them safe?
<><><>
As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
Before you do any work yourself,
on electrical circuits, equipment or appliances,
always use a test meter to ensure the circuit is, in fact, de-energized.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
Who can you get to fix your electrical problems?
I'm a licensed electrical contractor in California i can fix it if your in California.
What is a 1943 penny that sticks to the magnet and has an S on and looks silver colored worth?
Uncirculated examples sell for $1 to $2. In any lower condition a dealer may give 5 or 10 cents. He already has rolls of them that he can't sell.
== == You are not allowed to change a four-wire outlet to a three wire outlet.
You can change a four wire cord to a three wire cord.
That is VERY different! === === <><><> I have answered this question at least 6 times. The 4 wire plug has a neutral and the 3 does not. An untrained homeowner who does their own plumbing can flood the house with water or sewage, on the other hand electricity can kill instantly. I wouldn't want to gamble my family's lives on my incompetence. 3 wire plugs are old and outdated. Way back in the old days they didn't ground equipment so plugs didn't have a ground. (Remember the old 2 wire 110V outlets on houses built before the 50s?) A few people got killed so they decided to add a safety wire. It took them longer to catch on with heavy appliances, but eventually they did. That it what the fourth pin is. Since many homes still have the 3 wire plug it is allowed in older homes. New homes must use the new 4 wire plug. Changing your 4 wire cord to a 3 wire cord is the same as plugging a 3 wire 120V appliance into one of those 3 prong to two prong adapters they sell. Your appliance works now, but is ungrounded. Don't listen to anyone who says to replace the new up-to-code plug with an older plug. That is the same as replacing your 3 prong 120V outlets with old two prong outlets! Ignore anyone who tells you to do so, they think they know a lot more than they actually do. Buy a new cord. It is cheap and safer. IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
If you do this work yourself, always turn off the power
at the breaker box/fuse panel BEFORE you attempt to do any work AND
always use an electrician's test meter having metal-tipped probes
(not a simple proximity voltage indicator)
to insure the circuit is, in fact, de-energized.
Should old wiring be replaced?
There is no requirement to replace old wiring unless new changes are being done to an old circuit that does not meet current code, in this case all the old wiring in that circuit must be replaced.
It is entirely up to you if you want to replace old wiring or leave it as is (even if it looks unsafe) when no new changes are being made to the old circuit (e.g. you open a wall to do plumbing work and find antique "knob and tube" wiring with insulation problems - you do NOT need to replace any of this old wiring if you did not change its circuit in any way).
Many houses in this area have unsafe 2 prong outlets installed in the 1950s that were designed for use interchangeably on 115V 15A and 230V 8A circuits, but their design allows 115V 15A, 115V 20A, or 230V 8A plugs to be inserted without the user knowing they are plugging into an incorrect circuit. But unless something else is changed on a circuit containing these unsafe outlets they may all be left as they are, but every one of these unsafe outlets on the circuit must be replaced with safe 2 prong if anything is changed (3 prong if the circuit is upgraded to 3 wire grounded wiring).
About the only thing that could force rewiring the entire building is replacing an old screw in fuse box with a modern breaker box, as this changed to feed end for all circuits.
----------------------------------------------------------------------------------------------------------------------------------------------If the wiring has rubber insulation for the conductors you should definitely replace it with modern pvc-based wiring. To protect your electrical outlets and appliances - and also for safety reasons - you should also upgrade the breaker box. If you have old wires which are made of copper that has pvc-based insulation you can leave them as they are but only if they are still in good condition. If the wires are made of aluminum or if they don't look safe - for instance if the insulation is damaged - you should replace them immediately.
Answer
Old wiring may be safe if left alone, not overloaded or abused, and was originally "up to code". However, old rubber insulation with cloth coverings can become brittle and literally turn to dust if jiggled. This often occurs in overhead lighting outlets where heat from lights has dried and damaged the insulation. These old installations must be replaced if they are to be touched in any serious way (e.g., undoing clamps or other fasteners), otherwise they become unsafe. In other words, you should not simply pull out the old fixtures and devices and install new ones; you will need new wiring, and if you're getting new wiring, you should (must) get new circuit breakers.
You can expect your main electrical panel and meter to last 30 to 40 years before they start to need to be replaced. The wiring in the wall can last a bit longer but when it gets to be 50 to 60 years old you're better off replacing it if you can.
Answer
In the late 1940s a type of cable called "Romex" was introduced in the United States, using PVC insulation for the individual copper conductors with a paper wrap and braided fabric overwrap. It is usually black or silver in color. This type of wiring is still safe today, although early Romex cables didn't contain a third earth ground wire, as required by current electrical codes. Houses with this type of wiring usually have outlets with just two slots, lacking the third hole for 3-prong plugs, although sometimes homeowners have replaced the outlets with the 3-prong type in violation of the National Electric Code (NEC). Current Romex cables have a third copper conductor that connects to earth ground and the outer jacket is molded PVC plastic instead of braided fabric.
Take a look at your fuse box or breaker box. If it still contains the old screw-in fuses, chances are that the wiring in the house is outdated and should all be upgraded to modern Romex or "NM" type cable.
What is the definition of amperes and watts?
The definition of the ampere is : 'that constant current that, if maintained in two straight parallel conductors of infinite length and negligible cross-sectional area and placed one metre apart in a vacuum, would produce between them a force equal to 2 pi x 10^-7 newtons per unit length'.
Some places have 120 Volts and others 240 Volts What is the advantage of one over the other?
The answer given below refers only to USA, Canada and other countries using the same type of 60 Hz, 240 Volts "balanced around ground" system for standard mains power supplies to homes, offices, etc. Basically, it comes down to reducing the amount of lost power due to resistance of the wires in the walls of your home. Higher voltages can deliver more power to a load, with less power lost in the transfer. The downside is that higher voltages are more dangerous, and require more insulation to keep the wires safe to touch.
The long explanation
The reason behind why it can transfer more power, is a bit complicated. It all comes down to Joule's laws. Power used (P) is equal to Voltage (V) times Current (I). (P=I*V) So twice the voltage will transfer twice the power. So why not just use double the current, and avoid the safety issues with higher voltages?
Wires conduct electricity, but they also have some resistance. The more the resistance, the more power is lost due to heat. The power loss in wires can be calculated by using the equation P(loss)=I^2*R (or current times current times resistance). We'll ignore resistance for now, and assume it's constant. If you double the amount of current going through a wire, you quadruple the power losses and heat generated by 4 (2 * 2 = 4). So by using twice the current, you have transferred twice the power, but are now losing 4 times more power in the wires. The amount lost is small, but not trivial.
So let's say we want to cut our power losses by a factor of 4, while still transmitting the same amount of power. Remember the equations P(loss)=I^2*R and P(used)=I*V.
We can double V and halve the I and still get the same amount of power:
1/2*I * 2*V = I*V = P(used)
This will cut our power losses by 4:
1/2*I * 1/2*I * R = 1/4*P(loss)
Or, we could cut the resistance by 4 and leave I and V alone:
I*I * 1/4*R = 1/4*P(loss)
To do this though, we would need to increase the size of our wires which can get expensive, and is much more difficult to install.
There are other much more complicated reasons as well, dealing with mutual inductance and power factor correction, but they can be ignored as they're way outside the scope of this answer.
Any such attempt with a meter would just destroy the meter. Why not just find out which breaker/fuse controls the circuit and see what the breaker/fuse is rated at. Also find out what the wire size is. For a 20 AMP circuit you MUST have 12 gauge wire. There are other requirements but those two seem to be about the most significant. As has been stated, a meter won't help. The breaker prevents excessive load to be placed on the wiring so any 20 amp circuit would be limited by the breaker and there would be no other way to determine if a circuit is 15 Amp or 20 Amp other than to check at the breaker panel. Also, if someone just put a 20 amp breaker on a 14 gauge wire you have a serious fire hazard. As the above post suggests, have a professional check this out for you, it's too dangerous to make assumptions. <><><> Your description of "20A dedicated line" makes me think that you are needing a circuit for a heavy power-using-device that needs it own circuit (without any other receptacles or devices). If that is the case, then a meter can be used (with difficulty) to determine if any other outlets are connected to the same circuit. First turn off the power on the receptacle. Then check to see if any other receptacles are also dead. If so, they are probably on the same circuit and your receptacle is not a dedicated supply. <><><> Another method is to use a circuit tracer (available at Lowe's and other hardware and electrical supply stores). Plug the transmitter into the questionable receptacle, then use the receiver to check other receptacles to see if they are on the same circuit. Receptacles on the same circuit will cause a continuous fast beep (or other signal depending on model). You can also trace the circuit to the circuit breaker panel to find which breaker it is connected. It should be a 20-Ampere-trip breaker to make full use of a dedicated 20 A receptacle. <><><> Borrow an amp clamp and find the breaker in question. Clamp it around the neutral for that circuit (This takes a friend helping). Plug in a significant load like a hair dryer and have the friend turn in on and off while you watch the meter. It should read zero, then 8-10 amps then zero, etc. Plug loads in outlets that you think the contractor absconded the circuit from. The amps from those outlets should never show up on the amp clamp. Make sure the wire is 12 awg. A 12 awg wire will not push in the stabs of a 15 amp receptacle. SAFETY ADVICE
Before you do any work yourself,
on household electricity supplies, equipment or appliances,
always turn off the power
at the breaker box/fuse panel BEFORE you attempt to do any work AND
always use an electrician's test meter having metal-tipped probes
(not a simple proximity voltage indicator)
to ensure the circuit is, in fact, de-energized. IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
What to do in the event of an electric shock?
If you have no ill effects, file it as a learning experience. If you have any doubt about the severity of the shock, or if the electricity went into your body and out across a considerable portion of your body, get medical attention immediately.
For example, if the shock traveled in one hand and out the other, it crossed your chest and may have impacted your heart or lungs. This is why as electricians we try only to have only one hand at a time engaged in hot work. We'll put one hand behind our backs or one hand in a pocket. An electric charge in one finger and out another on the same hand is not likely to be life-threatening.
