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Electrical Wiring
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4,935 Questions
I can see that the best answer has already been given (the units aren't even remotely close). But suppose that what the asker meant was 125 kVA? In that case, it can be answered.
VA (or Volt-Amperes) is what's used to represent current consumption when the circuit runs on any form of alternating current (AC). Watts (W) don't apply, because of the inherent properties of a changing waveform. To properly calculate the actual put-into-use (or effective) power, one would have to take the entire circuit into account.
But, to answer the speculated question, I would say - anywhere between 125 kW and 0 kW, depending if the load is purely resistive, or purely capacitive in nature, respectively.
(this answer provided for the benefit of Google click-throughs, mostly)
How do you wire a single voltage 3-phase motor with 12 leads?
12 Lead, Single Voltage, Wye Start - Delta Run. Wye start; L1 to 1 and 7. L2 to 2 and 8. L3 to 3 and 9. All joined together 6,12,4,10,5 and 11.
Delta run; L1 to 1, 6, 7, and 12. L2 to 2, 4, 8, and 10. L3 to 3, 5, 9, and 11.
To reverse the direction of the motor interchange L1 and L2 of the supply voltage.
What size wire is used for a 7.5 hp 240 volt single phase motor?
The rule of thumb for a single phase 240 volt electric motor is 7 amps for each horsepower. As this is a 7.5 h.p. motor you should use a 60 amp breaker wired with AWG # 6 copper to be safe.
How can you get a 240V single-phase power from a 120V 3-phase service?
First of all there is no common three phase 120 volt service. There is in North America a three wire 120/240 volt single phase service. That being said, if you want to change a 120 volt source to 240 volts it must be done with a transformer. Its classification is a step up transformer. The primary side of the transformer H1 - H2 will be connected to the 120 volts. The secondary side of the transformer X1 - X2 will be connected to the 240 volt load. The transformer is sized by the current required by the 240 volt load.
Do you derate for a three phase line and load conductors in the same conduit?
Yes, there will be a de-rate applied to this type of installation. In the electrical code book the amperage rating of conductors is for allowable ampacities for not more than three copperconductors in raceway or cable. This is based on an ambient temperature of 30 degrees C.
If the ambient temperature of the conductors where the raceway is installed is over 30 degrees C the conductor amperages have to be reduced.
Where the number of conductors are from 4 to 6 conductors in a raceway, the conductors amperage has to be reduced by .8
What tester do you use to test an heat exchanger?
There are different types of heat exchangers. To get an answer the type of exchanger and what type of test you want to do should be stated.
Where do you connect the two leads of a shunt trip breaker?
Usually the breaker's shunt trip coil is tied to a corresponding current transformer that is sized to the amperage that is allowed to be passed through the breaker. These types of breakers can also be connected into a distribution monitoring device. If the monitor detects a phase reversal or phase loss or voltage rise or drop the breakers shunt trip coil is remotely energized and isolates equipment down stream from the fault.
Shunt trip coil circuits are also used as safety circuits where the situation calls for only one breaker to be energized at a time. If the second breaker is inadvertently closed, this would allow both breakers to be on, the second breaker's auxiliary contacts that are an internally part of that breaker will close the safety circuit and energize the shunt trip in the first breaker to causing it to open. So as you can see the two wires could be part of many wiring configurations depending on what situation calls for.
How many wires in a single phase motor?
There should be 2 or 3 wires. A hot, a neutral and sometimes a ground.
What gauge wire is required to run a 220 volt dryer circuit?
Wire size is based on the amperage the device draws. The wattage of the unit has to be included in the equation. Amps = Watts/Volts. Most homes in North America today are roughed in with a two conductor #10 cable. This size wire will allow a 30 amps. The electrical code allows this conductor to be only loaded up to 80% capacity so useful amperage is 30 x 80% = 24 amps. Watts = Amps x volts = 24 x 240 = 5760 watts. If your dryer's wattage is no larger that this a #10 conductor will be fine. If it is higher go to the next size wire which is a #8 rated at 40 amps. Same de rate has to be applied.
Where is the switch allowed to be placed in the bathroom?
In North America the switch can be placed either inside the room or outside the room. When it is inside the room it is placed on the opening side of the door so that when you enter the room, the switch can be flipped on. When the switch is located on the outside of the room a convenient placement is close to the door opening so that when you open the door the switch can be turned on in one continuous motion.
How much current is need for 12 VDC to flow through water?
First thing voltage does not flow current does. Voltage is the potential or pressure needed to make the current flow.
Current is directly proportional to the applied voltage and inversely proportional to the resistance of the circuit. To make the current flow you have to adjust the resistance of the circuit and that would be the water in this case. Salt added to water will make the water conductive so the resistance can be adjusted thereby making the current rise or fall depending on the water solution's resistive properties. The equation that you should consider using is Amps = Volts/Resistance.
What is it called when a dot is placed where two or more wires come together?
On an electrical schematic it designates that the wires are all connected together. It is called a connection point.
How 220V and 110V supply both come in home?
The power is supplied to the home from a center-tapped transformer with the center tap grounded. The voltage from the center tap to each leg is 110 to 120. However, the voltage between the two outer taps is 220 to 240. Entering the home, the wires to each (hot) tap are black and red, respectively, and the neutral is white. A forth, bare, ground conductor is included for safety. It is joined to the neutral wire at the breaker box.
How you would wire an electrical circuit?
There are many types of electrical circuits and each one is wired differently. Without knowing the specific circuit that needs to be wired, this question can not be answered.
What is the acceptable value of grounding resistance for any application?
An acceptable resistance for a ground to ground plate system is 2 ohms with a maximum allowance to 5 ohms. If the measured resistance is above 5 ohms more grounding rods or plates have to be added to reduce the resistance down to the acceptable levels.
Can you use one length of 3-wire cable to provide electricity to 2 separate circuits?
In countries that use a single phase split secondary service you can. In modern homes this is the type of circuitry that is used for kitchen split receptacles. On the receptacle the tie bar is removed from the "hot" side of the receptacle. A red wire of the three wire cable is placed on the upper terminal of the receptacle. A black wire of the three wire cable is placed on the lower terminal of the receptacle. The white wire is placed on the opposite side of the receptacle under the silver coloured screw. This will give you a full 15 amps capacity on the top portion of the receptacle and a full 15 amp capacity on the bottom half of the receptacle.
Are the three conductors in a single phase 240v circuit considered to be in parallel?
If the three conductors are in a single cable they physically are positioned parallel in relationship to each other.
True parallel conductors are combined to split the current. They have to be of equal length and size so that they split the load current between the two or three or four conductors. Conductors are paralleled so that multiple smaller conductors, which are easier to work with, can carry equally the total load current. To answer the question no, the three conductors in a 120/240 circuit are not considered to be in parallel. All three of these conductors could have a different current being carried by them depending on how the load is distributed.
Yes, since the current is the same through out the complete circuit. the design size of the conductor entering the circuit should be the same size as the conductor leaving the circuit.
What are raw materials for making copper wires?
Copper. The main grade of copper used for electrical applications is electrolytic-tough pitch (ETP) copper (CW004A or ASTM designation C11040). This copper is at least 99.90% pure.
Can you run a 240v wire from the electrical panel then put a junction box to run it where you want?
A 240 volt wire is the insulation factor of the wire. If you mean a 240 supply source from a distribution panel to a junction box then the answer is yes. You have to keep in mind that the box has to be accessible, meaning that you can get to the box to check the splice within the box. Don't bury the junction box behind the wall board.
When isolating two or more wires the installer can rely on what electrical component?
Any reference to isolating electrical components, an insulator is the first choice.
How many grounding clamps are permitted on one ground rod?
As long as the clamp is of an approved type only one is needed per ground rod.
What size breaker you would use for a 110 volt window air conditioning unit?
Breaker sizing is dependant on what the load amperage is that the breaker is connected to. If the amperage is not given but just the wattage, use this equation I = W/E. Amps = Watts/Volts. This air conditioner unit should be on a dedicated circuit receptacle. On these types of loads the conductor can only be loaded to 80% of the conductors rating. So a 15 amp breaker times 80% = 12 amps or Watts = Amps x Volts, 12 x 120 = 1440 watts. A 20 amp breaker times 80% = 16 amps or Watts = Amps x Volts, 16 x 120 = 1920. Once the breaker is sized remember to use the correct wire size to correspond with the amperage of the breaker.
