# How do you compute voltage drop and cable size over distance?

# Is there a rule to distance of cable from a power source to low voltage lighting without voltage drop and do you have to put transformers or outlets in the yard?

Voltage drop depends on the size & length of the wire and the wattage of the bulbs..
If they make an LED replacement bulb , you would hardly notice the voltage drop.

# How do you compute the voltage drop over a 500-meter underground cable if you have a 440-volt three-phase system?

THIS CONSIDERATIONS SHOULD BE STRICTLY FOLLOWED: SOUND ENGINEERING AND ACCEPTABLE ECONOMICS;.
1.DEFINE DEMAND LOAD - AFTER APPLYING POWER FACTOR AND EFFICIENCY FOR MOTOR LOAD…S AND ACTUAL SYSTEM VOLTAGE AND PHASE..
2. ONE WAY LENGTH OF WIRE OR CABLE - FT. (AWG) OR MTR. (SQ.MM) SELECTION.
3. MULTIPLY BY 125% TO THE CALCULATED LINE CURRENT TO GET AMPACITY REFERENCE.
4. LOOK OR SELECT THAT NEAREST RESULT TO ANY LOCAL CABLE SUPPLIER CATALOG OR NEC TABLES AND MATCH IT TO CORRESPONDING CABLE SIZE..
5. APPLY DERATING FACTORS - ALSO AVAILABLE TO NEC OR CABLE SUPPLIERS AND DEFINE THE FF:.
A. MEDIUM OF INSTALLATION - PVC OR RSC CONDUIT, CABLE TRAY OR CABLE LADDER OR TRUNKING, THROUGH, ETC..
B. AMBIENT TEMPERATURE - INDOOR OR OUTDOOR?.
C. GROUP FACTOR - CONSIST OF CABLE SPACING AND DISTANCE TO WALL OR INSIDE CONDUIT INSTALLED IN TRAYS OR UNDERGROUND.
6. APPLY DERATION IN WHICH RESULT IS LESS THAN ONE (1) TO THE PRE-SELECTED CABLE - THIS IS NOW YOUR ACTUAL FOR SELECTED CABLE.
7. DEFINE REQUIRED OR ACCEPTED VOLTAGE DROP IN PERCENT VALUE.
8. NOW USE THIS FORMULA:.
VDapp(APPLICABLE VOLTAGE DROP) = %Voltage Drop x Actual Voltage x 1000 divided by Derated Current x One Way Length x 100.
9. THE RESULT WILL HAVE A UNIT OF -- mV/A.Mtr OR MILLIVOLT PER AMPERE-METER.
10. NOW COMPARE IT TO AVAILABLE TABLES FOR VOLTAGE DROPS OF CABLES - IF IT IS LOWER THEN SELECT THE NEXT SIZE OR WHICH EVER MEET THE REQUIREMENT.

# How do you calculate voltage drop in a cable?

The answer to this question is simply ohms law. For most cables the resistance of the cable per meter will be defined by the manufacturer, so firstly multiply this by the leng…th of the cable you are using. Then apply ohms law V=IR. This will give you the voltage drop across the cable. In most cases for domestic use, this value of R is so small the voltage drop is negligble, though using a cable with the lowest value R will give you the lowest voltage drop for any application. If you're referring to a voltage drop in an Electrical Network the calculation becomes abit more complex and involves solving some implicit and explicit equations (assuming you know the voltage and power factor at the sending end and the real and complex powers consumed at the receiving end). If you wish to know more about this calculation let me know. THIS CONSIDERATIONS SHOULD BE STRICKLY FOLLOWED: SOUND ENGINEERING AND ACCEPTABLE ECONOMICS; 1.DEFINE DEMAND LOAD - AFTER APPLYNG POWER FACTOR AND EFFECIENCY FOR MOTOR LOADS AND ACTUAL SYSTEM VOLTAGE AND PHASE. 2. ONE WAY LENGTH OF WIRE OR CABLE - FT. (AWG) OR MTR. (SQ.MM) SELECTION 3. MULTIPLY BY 125% TO THE CALCULATED LINE CURRENT TO GET AMPACITY REFERENCE 4. LOOK OR SELECT THAT NEAREST RESULT TO ANY LOCAL CABLE SUPPLIER CATALOGUE OR NEC TABLES AND MATCH IT TO CORRESPONDING CABLE SIZE. 5. APPLY DERATING FACTORS - ALSO AVAILABLE TO NEC OR CABLE SUPPLIERS AND DEFINE THE FF: A. MEDIUM OF INSTALLATION - PVC OR RSC CONDUIT, CABLE TRAY OR CABLE LADDER OR TRUNKING, THROUGH, ETC. B. AMBIENT TEMPERATURE - INDOOR OR OUTDOOR? C. GROUP FACTOR - CONSIST OF CABLE SPACING AND DISTANCE TO WALL OR INSIDE CONDUIT INSTALLED IN TRAYS OR UNDERGROUND 6. APPLY DERATION IN WHICH RESULT IS LESS THAN ONE (1) TO THE PRE-SELECTED CABLE - THIS IS NOW YOUR ACTUAL FOR SELECTED CABLE 7. DEFINE REQUIRED OR ACCEPTED VOLTAGE DROP IN PERCENT VALUE 8. NOW USE THIS FORMULA: VDapp(APPLICABLE VOLTAGE DROP) = %Voltage Drop x Actual Voltage x 1000 divided by Derated Current x One Way Length x 100 9. THE RESULT WILL HAVE A UNIT OF -- mV/A.Mtr OR MILLIVOLT PER AMPERE-METER 10. NOW COMPARE IT TO AVAILABLE TABLES FOR VOLTAGE DROPS OF CABLES - IF IT IS LOWER THEN SELECT THE NEXT SIZE OR WHICH EVER MEET THE REQUIREMENT. you'll need to know the resistance of the conductor. copper has a certain amount of resistance per length. there are charts available on this

# How do you compute the voltage drop over a 500 Meter underground Teck cable if you have a 230 115 Volt single phase system?

You have to know the connected load amperage is at the end of the cable to do the calculation.

# How do you compute voltage drop?

The answer will depend on many factors such as: .
distance between the two points for which a voltage drop is to be calculated i.e the length of the cable run .
wire size …and material (copper, aluminum...) .
type of insulation used in the cable .
type of cable fixing (in the open air, along a wall, in a duct, underground, etc.) .
expected ambient temperature at full load For more information please see the Related Link and the answers to the Related Question s shown below.

# How can you limit voltage drop in a power cables?

To do this you effectively have to reduce the resistance of the cables. This normally would mean changing the cables for some made from a material of lower resistivity or larg…er cross sectional area or both. If you are restricted in the choice of cable you can run them in tandem to halve the resistance or use greater multiples still, providing that standard safety procedures are observed. If mains voltages are concerned the work must conform to part P of the building regulations.

# You have load 200Amp long 200meter how calculate voltage drop and what size cable can used?

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.

# Can you apply a 5 percent voltage drop on a 600 meter run to reduce your cable size?

This depends upon your application. What is the tolerance of the end device? In other words what is the manufacturers specified Voltage range? The % of voltage drop as given i…n the NEC is a FPN (Fine Print Note) and is therefore a recommendation and not a code requirement. Some States however will specify the allowable % of voltage drop as part of their rules. Typically they will follow the NEC FPN which is 3% for a branch circuit and 5% total for feeder and branch circuit. So if you are running a 240V line 600m you should only have 5% drop (12V) from the service to the end device/equipment. If 228V is within the allowable operating range of the equipment/system it feeds then that is acceptable.

# How can voltage drop be computed for a resistor?

Ohm's Law: Voltage = Current times Resistance

# What is voltage drop when utilized with cable runs?

A: ANY CABLE will have a definite impedance and if current flow there is going to be a definite voltage drop because of it

# When is a voltage drop calculation considered when determining the cable size?

The voltage drop calculation is considered when you know the size of the load (in amperes) to be supplied and the distance the cable will need to run. In Canada the volt drop …for a branch circuit cannot exceed 3 percent. Always consult a professional when installing electrical equipment.

# Will voltage drop over cable distance?

If the voltage is supplying any current through the cable, i.e. ifthere is any 'load' at the end, then the voltage will drop through thecable.

Answered

# How do you compute the voltage drop over a 500-meter underground cable?

You need the voltage drop per meter, from data on the cable, and then multiply by 500. Alternatively find the resistance per metre of a single cable of the same wire size, fr…om wire tables, then multiply by 2 x 500 x resistance (in ohms) x current (in amps).

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# How do you compute voltage drop and cable size over distance in israel?

You can find it out from wire tables. It depends on the current inamps and the material used (copper/aluminium), but not on whichcountry you are in. Try searching for wire tab…les and look forvoltage drop per 100 metres or such.

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# How do you compute voltage drop and cable size over distance in the UK?

If you are referring to residential wiring, then refer to the appropriate tables in BS 7671:2008 Requirements for Electrical Installations (the IEE Wiring Regulations ). …It's too complicated to be answered in this forum and requires prerequesite knowledge you may not have.

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# How do you compute the voltage drop over a 500 meter underground cable if you have a 440 volt three phase system?

You need two more pieces of information: (i) what is the current being drawn, or the load in kVA, (ii) how thick is the cable. Then look up the wire resistance in ohms per met…er for the cable, multiply by the length (500) and multiply by the current, then that is the voltage drop.

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# What are formula to calculate cable size and voltage drop?

The formula to calculate cable size and voltage drop is Vdrop =current x distance times 2 times Ohms per 1000ft times 0.001.