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Electrical Wiring
Ask questions here about proper wiring and electrical installation here.
4,935 Questions
Why does a bulb not fall down hanging with ceiling?
Because the light bulb is physically screwed into an electrical socket. The socket (and fixture) are physically attached by fasteners to the beams in the ceiling. This is a mechanical solution of space requirements.
Why doesn't an animal get shocked by a stock tank heater?
An animal does not get a shock from a stock tank heater because the heater is grounded back to the distribution panel. Any small tingle voltages will grounded so that the live stock does not become the grounding medium.
An electrical circuit is a path which electrons from a current source flow. Electric current flows in a closed path called an electric circuit. The point where those electrons enter an electrical circuit is called the "source" of electrons. The point where the electrons leave an electrical circuit is called the "return". The exit point is called the "return" because electrons always end up at the source when they complete the path of an electrical circuit. The part of an electrical circuit that is between the electrons' starting point and the point where they return to the source is called an electrical circuit's "load".
---Nerd
What is an AC single phase 2 wire system?
two wires coming off the secondary of the transformer ex. residential voltage of 120 volts each line, and one neutral wire, L1 to neutral is 120 volts, L2 to neutral is 120 volts, L1 to L2 is 240 volts.
AnswerA single-phase, two-wire, system comprises a line conductor and a neutral conductor. In European countries, the line conductor for a residential supply is at a nominal potential of 230 V with respect to the neutral.
In North America, a 'split phase' system is used for residential supplies; this is a single-phase, three-wire, system comprising two line conductors which and a neutral conductor. The nominal potential difference between the line conductor is 240 V, while the potential of each line conductor with respect to the neutral is 120 V.
Can you run a 7.5 hp 3 phase motor on solar energy?
The output from solar panels is a d.c. voltage which, using an inverter, is converted into an a.c. single-phase voltage. So under normal conditions, the answer would be no.
How do you hook up a mono block amp?
the difference between a mono block and stereo amp is this: a stereo amp sees half of ohms you give it ( that is if you are trying to bridge it), the mono block see whatever ohm load you give it.
Why do you have voltage to ground but not voltage phase to phase?
There is phase to phase voltage in 3 phase system.
AnswerYou don't get voltage 'phase-to-phase'; it's 'line-to-line'!
What minimum fuse rating is needed for a 12 volt circuit when using one 48 watt bulb?
The formula you are looking for is Watts = Amps x Volts. Amps = Watts/Volts. This comes to 4 amps load. Minimum size fuse would be 5 amps.
How do you check to see if electric motor windings are delta or Y?
in a delta configuration the current is split between the phases, as opposed to a wye configuration where the current will be equal on all phases.
and vice versa for voltage.
50 Hz is the frequency of alternating current (ac) used by national electricity power services in Europe and several other world areas whilst 60 Hz is used in USA, Canada and many other countries in the world.
50 Hz means or specifies "50 cycles per second".
Hz is the international technical abbreviation for the scientific unit of frequency, the hertz.
What is an electrical Britannia Splice?
The Britannia Splice is a connection between large solid wires. Several inches of each wire's insulation is removed and a ninety degree bend is made about a half inch from each end. The two wires are laid next to each other, with the bent ends separated by several inches. Another smaller wire, the wrapping wire, is wound around the assembly, starting from the center, in such a fashion that some turns go past the bent ends, after the point where the wrapping wire is wrapped on only one wire. The bent ends are then trimmed close.
While not as popular as the Long Tie Western Union joint, if properly made and soldered, the Britannia Splice is a very good splice.
How is an appliance grounded when it has 2 prong plug?
Assuming inside the lighting/distribution panel, the Neutral bar is "bonded" to the ground bar. Then the neutral prong (usually larger) of the receptical is then directly wired to the Neutral bar in the panel. The above technique keeps the NEUTRAL at GROUND potential, however, the metalic frame of the appliance remains UN-GROUNDED if the supply cord is only 2-wire. The NEUTRAL connection inside the appliance is not allowed to be bonded to the frame of the appliance. Therefore, the un-grounded metal frame of the appliance can become a shock hazard if there is a fault in the appliance's internal wiring
How can intermittent faults in aircraft wires be detected?
One way is through the use of time domain reflectometers (TDRs). In these, a signal is sent down the live wire and reflected back by certain breaches that could cause damage to the electrical system. Another type of reflectometer is called a noise domain reflectometer. These devices monitor the existing signals without generating one of its own. This method could be very useful to monitor the aircraft wiring during the flight.
The trick, of course, is whether you are trying to detect the fault while it is running or while it is off with basics TDR's good for the while the Airplane is off but advanced TDR's required to find faults during operation.
Some legacy troubleshooters believe that there are no such things as "Intermittent Faults"; only Intermittent Symptoms. Even as this reflects simple semantics, it can assist in the thought process for understanding root causes for intermittent symptoms. If you use existing multi-meter, TDR's and in worst cases "meggers", you will only see those types of faults limited to the individual tool.
Aircraft electrical systems involve much regarding load(s). Power system wiring can be approached differently than that used in signal lines. Technologies should be more centered on the Systems Engineering approach. For example, intermittent operations within a high frequency coax or triac cable on System A can require a significantly different tool than that used on flight deck overhead lights or panel illumination. As stated in the first two paragraphs, if you use a TDR and can see the failure constantly it is thereby not an intermittent fault. It is a hard failure, only unseen by the type of tool you are using.
Recently, many organizations are claiming to find "intermittent faults" with their devices and technologies whereas the marketing/sales theme is somewhat like chicken little. We may not have feasible technologies to locate cracks/open insulators that may touch airframe (or another wire) but we do have tools that can quickly assess many wires at one time (analyzer - Eclypse for example) that can see some of these failures as "hard" versus "Soft".
Please note that there is not a golden tool or silver bullet, nothing is 100% since the designs of our aircraft have not changed in regards to the electrical systems routing and management. Until we make changes we will have to deal with what is dealt from the OEM's.
What is the voltage to ground of 13800 volts line to line?
On a three phase system with a line to line voltage of 13800, a wye connection will give you a voltage of, 13800/1.73 = 7977 volts to ground.
What is clean earthing system?
A clean earthing system is a circuitry that connects the electric circuit to the ground. This defines the electrical conductors to the Earth's conductive surface.
How do you calculate absolute maximum current?
The absolute maximum current is used as part of a rating system, particularly for electronic components. It is a figure that a manufacturer will quote to indicate how much current can pass into or out of a device or a specific connection on the device. Exceeding that limit is likely to damage the device. The absolute maximum value is one that should never be exceeded but it is also normally higher than the maximum recommended current. The value is often measured during tests rather than calculated.
The question might refer to the amount of current that might be drawn by a device. In this instance, to calculate the absolute maximum current that a device or component might draw there are two pieces of information needed. The first is the voltage that is applied to the device. The second is the lowest possible resistance that the device can have. Devices such as resistors, filament lamps and heaters have a constant resistance but active devices such as amplifiers, computers etc. can change resistance as they operate. It can be hard to find the resistance with some devices but once it has been established, Ohm's Law can be used to calculate the maximum current using the equation current = Volts divided by resistance. It is normally much easier to measure the current using an ammeter rather than trying to find the lowest resistance.
How accurate are the readings of a megger test?
While using megger we only have to see whether resistance breaksdown at the upper value mentioned. Since megger generates high voltage we can check whether breakdown takes place or not.Megger has a range from o to infinity.So it is not possible to find accurate resistance,hence it is used as an insulation tester
In electrical what is the oms low?
Voltage(E)=Amps(I) x Resistance(R) (ohms)
use this formula to solve for other two.
A phase wire is the hot wire in a circuit if looking at single phase that would be the live (brown in the UK). If you are trying to find out which wire is your phase wire use a voltmeter connect the black lead to earth and red lead on the wire to be tested. If the circuit is on and you have a phase wire you will read voltage on the meter. If the circuit is off or you have the neutral(blue wire in the UK) you will read little or no volts.
Notice electricity is dangerous always use common sense if you don't know what you are doing find someone who does failing that put a hand in your pocket you will have less chance of killing yourself.
Answer'Phase' is the incorrect name widely used in place of the correct term, 'line'. The current version of BS 7671(2008), the IEE Wiring Regulations, has, at last, recognised the misuse of the term 'phase' in its previous editions.
In the UK, a single-phase AC line conductor has a nominal potential of 230 V with respect to the neutral. In Europe, a single-phase line conductor is normally colour-coded brown; in three-phase systems, the three line conductors are colour codes brown, black, and grey.
What would it cost to run a 3 phase induction motor?
Depends on the size. You can go from a few hp to many thousands of hp.
How do you wire a DPST switch?
A double pole single throw switch.
used to switch two lines at the same time.
Can you define the term Neutral in electrical terminology?
In a single phase system the neutral wire is the return path of the circuit and may be near ground potential, in multiphase systems it carries the unbalanced current.
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A neutral wire is always needed as the return path back to the power station for any single-phase circuit in which a single live wire feeds alternating current into the connected load.
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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.
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It can be confusing. The NEC refers to "grounding" and "grounded" conductors (very different from each other) but not a neutral. The neutral is what the NEC calls a grounded conductor. This is NOT the same as the "grounding" conductor, which is the green or bare wire (US systems) providing a safety earth.
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.
Three phase power is almost never supplied to a residence. Power is supplied in two 240-volt lines, referenced to ground, which is also typically wired, giving you three overhead (or underground) lines for supply to a typical residence. A larger apartment building might use three-phase power.
AnswerSome countries do indeed supply residences with three-phase supplies instead of single phase. For example, the recently-constructed, two-bedroom, villa in which I live here is Cyprus has a three-phase service and this can be confirmed by examining the three-phase energy meter and the three-phase distribution panel. I don't really know why this should be the case, other than for the purpose of load sharing, as the villa's load is typical of residences elsewhere.
What is the safest voltage for a power tool?
tell me what tools has 15% more power than another tool of the same line general power tools , what tools has 15% more power than another tools of the same line compare such as drills, circular saws.
Can you ground an electrical system on an old two wire system without putting in new wire?
(LIFE SAFETY WARNING! [disclaimer]
Electricity is dangerous!
You can be injured or killed!
Improper installations can cause fire, injury and death!
Should you be doing this yourself?)
- It is not possible, per se, to "ground" an entire old two wire electrical system.
- It is possible, however - and allowed - to provide a ground at an individual receptacle by installing a grounding conductor according to strict limitations.
- Many simple devices are "double insulated" and designed to be used without any protective ground connection. But some are not so you have to be sure of the differences between them.
- It is recommended to install a new grounded circuit for point of use service wherever a protective ground connection is required.
- The best advice anyone should give here is to call a licensed electrician!
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The answers above are correct, you cannot ground a two wire system without running new wires, however, you can make your circuit as safe as a grounded one by using a GFCI. A GFCI does not have to be grounded to operate as it measures the current flow in both legs. It ensures the live current is equal in value (amperage) to the neutral current. In the case that the currents are not balanced, that is when you are in a hazardous situation.
In a grounded circuit, the fault current is supposed to flow to the ground, keeping you safe. The GFCI on the other hand will trip and give you as good if not better protection.
If you wish to use a GFCI receptacle to protect your circuit, you may install it at the first receptacle of your circuit and tie the remainder of the circuit to the load side of the GFCI so that it will protect the whole circuit. This is legal in Canada, I am not familiar with the American laws, but I would think it is acceptable there too. I do advise to hire a qualified electrical contractor, he should know the laws.
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Using a GFCI with no ground to the load connections is compliant with code in the US as well. The receptacles with the floating ground (protected by a GFCI) must be labeled "No Equipment Ground." However, not sure if local inspectors in all states and/or localities will accept this, especially in some big cities - e.g. New York, which have very strict wiring codes, so it's best to check with a local expert.
DO NOT connect the ground to the neutral! Unfortunately I have seen this done and it creates a very dangerous situation.
ALWAYS CHECK WITH YOUR LOCAL WIRING SAFETY OFFICE BEFORE YOU ATTEMPT TO CHANGE ANYTHING ON POWER MAINS OUTLETS
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 electricians test meter having metal-tipped probes
(not a simple proximity voltage indicator)
to insure the circuit is, in fact, de-energized.
