Wire Wizard
Calculations Explained


Bambach have launched a Smartphone app called Wire Wizard.

This document will help answer questions you may have on:

  • How to use the app
  • The common scenarios where the app may be useful
  • Instructions on how to use the app and interpret the results

 

Voltage Drop

Common scenarios requiring voltage drop

  1. Determining the maximum distance that a cable can be run before it exceeds the maximum allowable voltage drop.
  2. Determine the minimum conductor size to run a given length
Instructions – Scenario 1 – Determining maximum length
  • Choose appropriate conductor size based on installation conditions and required current. See current carrying capacities.
  • Input supply voltage, current and whether its 3 phase or single phase
  • Choose the operating temperature. The operating temperature is often not known however the maximum operating temperature is. PVC is rated to 75°C, X-90 90°C etc. By inputting the maximum operating temperature, you are determining the worst case scenario for voltage drop.
  • Choose the maximum allowable voltage drop in the first roller (5% is maximum under installation guidelines).
  • Choose the appropriate conductor size based on current carrying capacity in mm² (found in point 1).
  • The maximum conductor length will be displayed in metres
Instructions – Scenario 2 – Determining minimum conductor size
  • Choose appropriate conductor size based on installation conditions and required current. See current carrying capacities.
  • Input supply voltage, current and whether its 3 phase or single phase
  • Choose the operating temperature. The operating temperature is often not known however the maximum operating temperature is. PVC is rated to 75°C, X-90 90°C etc. By inputting the maximum operating temperature, you are determining the worst case scenario for voltage drop.
  • Choose the maximum allowable voltage drop in the first roller (5% is maximum under installation guidelines).
  • Choose the required conductor length in metres.
  • The minimum conductor size to run the length will be displayed.
  • Check that this minimum conductor size is equal to or greater than the conductor size found in current carrying capacities. Both parameters need to be satisfied.

 

 

Short Circuit Current Rating

Common scenarios requiring short circuit current raiting

  1. Calculating permissible conductor short-circuit currents for majority of practical cases
Instructions
  • Select the conductor material type
  • Select the insulation. Each insulation type is rated to withstand a certain conductor temperature. The higher the temperature, the higher the current rating. The corresponding maximum temperature for each insulation material is displayed underneath the insulation designation.
  • Select the initial conductor temperature. This could be selected as ambient (considered to be 40°C) or the worst case scenario. The worst case scenario would be the temperature at which the conductor is carrying maximum load. i.e. PVC is 75°C, XLPE 90°C.
  • Select the permitted duration of the short circuit in seconds
  • Select the conductor area in mm²
  • The maximum current is displayed below in Amps

Current Carrying Capacity

Common scenarios requiring current carrying capacity
  1. To determine the maximum current that can be carried in a given cable and installation condition
  2. To determine the minimum conductor size to carry a required current in a given installation condition
Instructions – Scenario 1 – Determining maximum current
  • Select the insulation. Each insulation type is rated to withstand a certain conductor temperature. The higher the temperature, the higher the current rating. The corresponding maximum temperature for each insulation material is located next to the compound designation.
  • Select the cable type. The earth core does not count as an active core. For example a 2C + E orange circular cable would be considered a 2C sheathed cable.
  • Select the installation type. This is where the user will install the cable. If half the length of cable is exposed to the sun, then the entire length should be considered to be exposed to the sun.
  • Select conductor material. This is broken up into 3 choices. Cu solid/stranded relates to non flexing copper conductors (for example orange circular). Cu flexible is copper conductor with flexible stranding (for example panel flex). Aluminium relates to aluminium conductor.
  • Lastly, select the conductor size of the cable in mm²
  • The maximum current will be displayed in Amps
Instructions – Scenario 2 – Determining minimum conductor size
  • Select the insulation. Each insulation type is rated to withstand a certain conductor temperature. The higher the temperature, the higher the current rating. The corresponding maximum temperature for each insulation material is located next to the compound designation.
  • Select the cable type. The earth core does not count as an active core. For example a 2C + E orange circular cable would be considered a 2C sheathed cable.
  • Select the installation type. This is where the user will install the cable. If half the length of cable is exposed to the sun, then the entire length should be considered to be exposed to the sun.
  • Select conductor material. This is broken up into 3 choices. Cu solid/stranded relates to non flexing copper conductors (for example orange circular). Cu flexible is copper conductor with flexible stranding (for example panel flex). Aluminium relates to aluminium conductor.

 

Maximum Bending Radius

Common scenarios requiring maximum bending radius
  1. Calculate the general minimum bending radius for cables. Manufacturer may advise a different value
Instructions
  • Enter the outer diameter of the cable in mm
  • Select whether the cable is armoured or unarmoured
  • The minimum bending radius will be displayed in mm

 

Characteristic Impedance

Common scenarios requiring characteristic impedance
  1. Calculate the characteristic impedance on a uniform line such as coaxial cable or shielded twisted pair, based on measured capacitance and inductance
  2. Calculate the characteristic impedance on a uniform line such as coaxial cable or shielded twisted pair, based on dimensions of cable
Instructions – Scenario 1 – Measured capacitance and inductance values
  • Select the cable type from the available options
  • Input the capacitance measured between the cores or conductor and shield in pF/m
  • Input the inductance of the pair or coaxial cable in μH/m
  • The characteristic impedance will be displayed in Ω
Instructions – Scenario 2 – Dimensions of the cable
  • Select the cable type from the available options
  • Select the arrow on the right hand side of the input field
  • Select the cable type
  • Choose the insulation type. This will input the generic dielectric constant
  • Input the conductor diameter in mm
  • Input the distance between the midpoint of the 2 conductors or the diameter over insulation in mm
  • Input the outer diameter of the bunched pair, excluding the shield in mm (Applicable to shielded twisted pair)
  • Select Impedance at the top left section of the screen
  • The calculated capacitance will be inputted
  • Select the arrow on the right hand side of the input field
  • Input the distance between the midpoint of the 2 conductors or the diameter over insulation in mm
  • Input the conductor diameter in mm
  • Select Impedance at the top left section of the screen
  • The calculated inductance will be inputted
  • The characteristic impedance will be displayed in Ω

 

 

Conductor Size

Common scenarios requiring conductor size
  1. Calculate the conductor size based on the number of wires and wire size
Instructions
  • Input the number of wires in the conductor
  • Input the diameter of the wire strand in mm
  • The conductor area will be displayed in mm²

 

 

AC Resistance

Common scenarios requiring AC resistance
  1. To calculate the total core resistance due to inductive, capacitive and conductor current resistance.
Instructions
  • Select the cable type from the available options.
  • Select the conductor material. Tinned copper has a slightly higher resistance value than plain copper.
  • Select the conductor temperature. This could be selected as ambient (considered to be 40°C) or the worst case scenario. The worst case scenario would be the temperature at which the conductor is carrying maximum load. i.e. PVC is 75°C, XLPE 90°C.
  • Select the conductor area in mm²
  • The AC resistance is displayed is Ω/km at 50Hz

 

 

Capacitance

Common scenarios requiring capacitance
  1. Calculate the capacitance of a uniform line based on cable dimensions
Instructions
  • Select the cable type
  • Choose the insulation type. This will input the generic dielectric constant
  • Input the conductor diameter in mm
  • Input the distance between the midpoint of the 2 conductors or the diameter over insulation in mm
  • Input the outer diameter of the bunched pair, excluding the shield in mm (Applicable to shielded twisted pair)
  • The capacitance will be displayed in pF/m

 

 

Reactance

Common scenarios requiring reactance
  1. Calculate the reactance caused by the conductors of the cable(s)
Instructions
  • Select the cable type from the available options
  • Select whether it’s a multi-core or single core cable(s)
  • The layout at which the cable(s) are being installed
  • Select the insulation type. Each material type has its own dielectric value and will have different capacitance and inductance effects
  • Select the conductor area in mm²
  • The reactance is displayed is Ω/km at 50Hz

 

 

Resistance (Serial and parallel)

Common scenarios requiring resistance
  1. Finding series or parallel resistance of a simple circuit
Instructions
  • Select whether the circuit has series or parallel elements
  • Enter the number of elements
  • Enter the resistive values of each elements in Ω
  • The total resistance is displayed in Ω

 

 

Ohms Law + Power + Conductance

Common scenarios requiring Ohms Law, power and conductance
  1. Calculate the power, current, voltage or resistance of a simple circuit
Instructions
  • Select whether you want resistance or conductance
  • Select whether you want to calculate power, current or voltage
  • Enter in 2 of the 3 required values
  • The required value will be displayed