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The current-carrying capacity of a cable depends on a number of things in addition to its cross-sectional area; these include the type of conductor, number of cores, type of insulation, whether or not it is armoured, method of installation, etc. Accordingly, to determine its current-carrying capacity, you will need to refer to your national electrical code. For example, in the UK, BS 7671:2008 Requirements for Electrical Installations contains tables for all standard cable types, specifying current-carrying capacity, voltage drops, etc.

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12y ago
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14y ago

Yes, you calculate the size of cable (wire) according to current of the connected load.

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Q: How do you calculate the current capacity of a cable when the cable size is known?
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How we calculate magnitude of current in circuit?

It is nothing but how much current or voltage taken in the circuit. It is known as Magnitude.


How do you calculate the current of the secondary side of the transformer without a load are impedance known?

Without a load the secondary current is zero, by definition.


What must be known to calculate current Ohm's law?

I(current) = V(voltage)/R(resistence) Example : 220 V / 5000 Ohm = 0.044 A (Ampère) = 44mA


What muct be known to calculate current using Ohm's law?

I(current) = V(voltage)/R(resistence) Example : 220 V / 5000 Ohm = 0.044 A (Ampère) = 44mA


How do you calculate burden resistor fo current transformer?

The method I have seen employed is to estimate the maximum current that will flow in the secondary side of the CT due to fault currents on the primary side, and calculate the total load (resistance) on the secondary side, including the CT resistance, cable resistance (2 way for ground faults, 1 way for three phase and L-L), resistance of any meters/relays connected to the CT. Once this is known, the voltage rise in the CT can be determined to see if the CT is likely to saturate.Alternately, you can determine the VA burden by the above, VA = V*I = (I*R)*I, using Ohm's law.The above answers the question of how to calculate the VA burdon on a current transformer. The VA burden of a CT is determined by the resistivity of the CT, multiplied by the current squared through the secondary. In general, this will be provided by the manufacturer in the form of a CT burden characteristic, developed through testing of the CT in question, not through calculations.

Related questions

How we calculate magnitude of current in circuit?

It is nothing but how much current or voltage taken in the circuit. It is known as Magnitude.


How do you calculate the current of the secondary side of the transformer without a load are impedance known?

Without a load the secondary current is zero, by definition.


How do you calculate primary AC for 3 phase ac input if output load dc current is known?

DC Current divided by 1.225


How thick is the cable to conduct 22.5 kw of power?

Cable doesn't conduct power, it conducts current. Either the voltage and load must be known or the amperage the cable will need to conduct to determine the size of the cable. Once the amperage is known, there are multiple tables online that have cable size and amperage. Do a Google search for "conductor amperage" for examples.


How do you calculate the current?

If the wattage of a load is known then the current can be calculated. Watts equals amps times volts. You would use the following formula, Amps = Watts/Volts.


What must be known to calculate current Ohm's law?

I(current) = V(voltage)/R(resistence) Example : 220 V / 5000 Ohm = 0.044 A (Ampère) = 44mA


How do electric compainies usually calculate electrical energy?

They usually just measure current used and assume a known voltage.


To calculate the energy released within a calorimeter the volume temperature change and specific heat capacity of water must be known is this true or false?

that will be true


How many watts in 0.45volts?

Watt is the unit of power. So in order to calculate power, both the voltage and current should be known.


How do you calculate the load and cable size?

The first thing that has to be done is to determine what the amps or wattage of the connected load is. This can be done from the nameplate on the equipment or device to be connected. If only the wattage is found use the following formula Amps = Watts/Voltage. Once the current is known the cable size is determined from a table of, allowable ampacities of 3 copper conductors in a raceway, in the electrical code book that is used in your specific region.


What is cable media'?

Cable media is a type of media which is known as cable media :)


How calculate unknown resistance?

-- Connect a source of known, small voltage across the ends of the unknown resistance. -- Measure the resulting current through the unknown resistance. -- Divide (small known voltage)/(measured current). The quotient is the formerly unknown resistance.