Wire Sizing

This dialog helps you analyze an appropriate wire size for a selected device's connected power wiring.

Accessed when you select a component and select the Wire Sizing option from either of the following locations:

Right-click popup menu
Modify Component ribbon

The Wire/Core Sizing and Sustainability tool provides these key features on a per-picked-device basis:

Size power wiring per electrical code standards (ex: National Electrical Code: NEC 2008 and NEC 2011).
Account for de-rating factors such as fill, ambient temperature, wire type, voltage drop.
Analyze sustainability (ex: power loss cost versus oversized wire cost; option for multiple smaller conductors per phase).
Push selected wire size assignment out to selected wires for reporting.
Output report summarizing the picked device's electrical requirements, its selected wire size, and optionally some sustainability estimates comparing wire costs versus annual energy loss costs in the wiring.

Note: This tool is meant to work off of an initially picked device, not initially picked wires. It helps you analyze an appropriate wire size for the device's connected power wiring.

Step 1: Load Type

This tab identifies the selected device's load amp value (Full Load Amps : FLA). This value can then drive selection of an appropriate wire size in the subsequent tab. If additional information is provided such as system supply voltage and phase, then additional analysis related to voltage drop and power losses will be enabled on the Step 2 and 3 tabs.

Setting	Description
Symbol Property/Value	Displays properties and values carried on the selected device. This is for display only! No direct editing is supported here.
Standard	The electrical code standard that the tool should follow regarding sizing of wires / cores. If the standard is set up to cover either AWG or Metric wire sizes, then there may be two standards selections available, one for each wire size standard (ex: 2011 NEC AWG; 2011 NEC METRIC). Note: use the companion wire sizing database editor utility to view/edit/add electrical code standard settings.
Category	Drives what category of data is displayed in the dialog's lower load size selection table.
System Voltage	Supply voltage value that is used in voltage drop calculation. It also affects what data is displayed in the dialog's lower load selection table.
Phase	Supply voltage phase (single or 3-phase) and is used to filter the data displayed in the dialog's lower load selection table.
Type	Type of load based upon Category selection above. Helps drives what data is displayed in the dialog's lower load selection table.
Rated Voltage (V)	Device rated voltage that, along with device FLA, is used to filter the load selection table display and is also used to calculate the device's kVA value
Frequency (Hz)	Electrical AC power frequency (ex: 50 or 60 Hz). This value is used to filter the load selection table display.
FLA	Device Full Load Amps" value. This is either filled from data held in the selected entry of the dialog's lower load selection table or is a manually typed-in value.
kVA	Device size measured in kilo-Volt-Amps. This value is tied to the FLA edit box value and the dialog's phase selection. Manually forcing a kVA value into this edit box will trigger a recalculation of the FLA value.
FLA Multiplier	Multiplier of FLA amp value for certain load types based upon electrical code requirements (ex: 1.25 for AC induction motors per the NEC).
FLA (Other)	Optional FLA value of other loads to be fed from a common set of power wiring can be manually entered into this edit box.
kVA (Other)	Optional kVA value of other loads to be fed from a common set of power wiring. This value is tied to the FLA (Other) edit box value and the dialog's phase selection. Manually forcing a kVA value into this edit box will trigger a recalculation of the FLA(Other) value.
Maximum Load	Maximum load amp rating, the sum of (FLA x FLA_Multiplier) + FLA(Other).
Total kVA	Sum of kVA + kVA(Other).
Load Selection Table	User's row pick from this table pushes the row's FLA value into the FLA edit box. This then drives the calculated Maximum Load value which, in turn, is key in selecting the minimum wire size in the Step 2 tab below.

Manual FLA Entry

A FLA value can be manually typed into the FLA edit box and override any default FLA value held in the edit box that came from a selected row in the Load Selection Table. It will also trigger the kVA edit box value to recalculate. In like manner, any new row selection from the table will override the current FLA value held in this edit box (and the calculated kVA value), whether the original FLA value had been manually entered or not.

FLA Versus kVA Entry

The FLA and kVA edit box pairs are linked. Manually entering a value into one will update the other. Note: the conversion between FLA and kVA is affected by the row's Phase value selection.

System Voltage Versus Rated Voltage Entry

The system voltage value is used for voltage drop calculations : what percentage of the selected system voltage is lost in the power wiring as it makes its way to the connected load. The rated voltage is used for calculating the load's rated kVA value or effective impedance value based upon the load's rated FLA value. There is currently no validation that the selected system voltage is within range of a selected load's rated voltage. This is the responsibility of the user.

Step 2: Wire Size

This tab takes the Maximum load amps and the FLA values from the Step 1 tab and various settings and de-rating factors to determine the minimum wire size based upon the Step 1 tab's selected electrical code Standard.

Note: The top part of this tab shows the key selections made in the Step 1 tab. These are grayed-out and not editable from this tab (but to adjust, temporarily go Back or re-select Step 1 tab and make any needed adjustments and then return to this Step 2 tab).

Setting	Description
Material	Wire material (ex: CU copper or AL aluminum)
Insulation Rating	Temperature rating of the wire's insulation. This affects the current carrying ampacity value for a given wire size. This is per the selected Standard.
Insulation Type	Insulation designation. This is for informational purposes only : it is not used in the ampacity calculation (the Insulation Rating listed above is the actual factor used).
Enable Parallel Wires and Max/Phase	Enable calculation for optional multiple smaller conductors per phase where the Max/Phase setting is the upper limit count of wires per phase to be considered). For the NEC standard, multiple wires per phase takes effect at wire size 1-0 AWG and higher.
Run Distance (one way) toggle, distance, and units	Turning the toggle ON and entering a one-way wire run distance and FT/Meters units enables voltage drop and sustainability calculations.
Power Factor	Optional power factor value that enters in to the voltage drop calculation.
Conduit Install Via	Optional raceway material type as defined in the selected Standard. This selection has a small effect on the voltage drop calculation.
Load Type	Optional load type characteristic that can affect a voltage-drop influenced change in the load's FLA value. Constant Amps: this load behavior assumes that the device exhibits a constant FLA amp draw and a simple voltage drop calculation. Constant Z (Constant Impedance): load device appears as a constant impedance value calculated from the load device's rated voltage, phase, and rated FLA values. The voltage drop in the power wiring is calculated based upon an adjusted FLA value that results from the reduced voltage (System Voltage : Voltage Drop) arriving at the terminals of the constant impedance load device. Constant kVA: (typical for AC induction motors) : device appears as a variable impedance load where the voltage reaching the device multiplied by the amps that flow through the device is a constant value (within a reasonable range of the device's rated voltage). For example, if the voltage reaching the device increases, the amp flow decreases (to hold the load's constant kVA rating), causing the voltage drop to decrease, causing the voltage reaching the device to increase, and so on until equilibrium reached.
Filter by Voltage Drop %	When toggled ON, the Wire Size Table will not show wire sizes that exceed the maximum allowed voltage drop percentage. For example, if this is toggled ON and the value set to 3%, only wire sizes that have a voltage drop value of 3% or less of the System Voltage value will be displayed for user selection.
Fill Correction range	This selection, per definition in the selected Standard, can apply a fill ampacity de-rating factor. The current carrying ampacity of a given wire size may be affected by the count of other current carrying conductors in the same cable or conduit/raceway. This de-rating is due to conductor mutual heating.
Ambient Temperature Correction range	This selection, per definition in the selected Standard, can apply an ampacity de-rating factor. The current carrying ampacity of a given wire size is affected by the highest ambient temperature that the cable, conduit, or raceway must pass through. The higher the temperature, the lower the ampacity limit on what a given wire with a given insulation temperature rating can safely handle.
Total Correction	The product of the above two de-rating factors. For example, if the fill correction de-rating factor is 0.8 and the ambient temperature de-rating factor is 0.91, then the total de-rating applied to the wire ampacity values if 0.73 (= 0.8 x 0.91). A 3 AWG copper wire rated at 100A maximum is de-rated to safely handle only 73A maximum (100A x 0.73).
Show All	Wire sizes that result in a Maximum Load value exceeding the wire's De-rated Ampacity value are displayed with red highlight. With Show All toggled ON, all entries are shown : even the red ones that each do not have adequate ampacity to handle the Maximum Load value. But if the Show All toggle is turned OFF, only valid wire sizes display : all red entries are suppressed.

Step 3: Usage Cost

This tab takes effect only if Step 2 tab's Run Distance toggle is turned ON. Step 3 takes the selected wire size and wire/phase counts (if the Enable parallel wires options turned ON) and various settings and de-rating factors on Step 2 tab to determine the maximum annual electrical energy losses in the power wiring. This Step 3 tab display also lists other wire sizes meeting the load's ampacity requirements. This gives the user an option to select a larger, more efficient wire size or multi-wire combination. Cost comparisons are displayed in the right-hand column of the table in the bottom half of this Step 3 tab.

Setting	Description
Usage Run-time Hours Per Year	User enters the annual hours that this set of wiring will feed the FLA value to the selected load device. This value used in the kWh energy loss calculation due to voltage drop in the power wiring.
Wire Cost	This estimate is for the power wires only and calculated for the defined one-way run distance. It does not include cost of conduit/raceway, ground/neutral wire(s), or installation / labor. Its purpose is to show the relative wire cost differential between a selected wire size and those wire sizes larger and smaller. The estimated one-time wire cost difference can be compared with the reoccurring kWh loss / year cost estimate to help guide in a sustainable design decision.
Wire Cost Editor	Displays a sub-dialog showing the current cost assigned to each wire type.
Wire commodity index	This is a correction factor temporarily applied to the wire cost data. For example, if the current design is not expected to reach the procurement phase for another year and the projected cost of copper wire is expected to be 10% higher by then, a commodity index value of 1.1 will take this anticipated increase into account in the comparison calculations.

Step 4: Reports

This tab provides means to output a customized report that summarizes the load and the selected wire size. This report includes not only information on the selected wire size but also shows valid wire sizes that met the minimum requirements.

Note: The top part of the 4 tab shows the key selections made in the Step 1 tab. These are grayed-out and not editable from this tab (but to adjust, temporarily go Back or re-select Step 1 tab and make any needed adjustments and then return to this Step 4 tab). The middle right-hand part of the dialog gives a summary of the selected load type and selected wire size.

Setting	Description
Report template selection	Browse to and select the desired .repx report template.
New	Creates a new report template.
Edit	Edit the selected report template.
Preview	Triggers report generation of the current load and wire size selection.

Wire Sizing/Sustainability Tool Dialog

This dialog displays after completing the wizard and enters you into an annotation mode.

Setting	Description
Device Properties	Rating: Load size rating value to be pushed out to the originally selected device (if the check box is toggled ON) when Update button is pressed. Amps: Load amp value to be pushed out to the originally selected device (if the check box is toggled ON) when Update button is pressed.
Wire Properties	Size: If toggled ON, this value will be pushed out to any wire or wires identified after the Select Wires button is picked followed by an Update button pick. Type: If toggled ON, this value will be pushed out to any wire or wires identified after the Select Wires button is picked followed by an Update button pick.