Bus Data

This dialog box includes the following areas and tabs:

See Common Tabs for information on the Location, Comments, Hyperlinks, or Collected Data tabs.

For DC buses, see also DC Bus - Base Voltage Specifications.

Figure 1: Bus Data Dialog Box

Connection Information

Option Description
ID Name

Uniquely identifies the equipment item. The program automatically assigns a name, but you can change it, if needed. The name can be up to 16 characters long.

For buses, the program automatically assigns the names BUS-1, BUS-2, BUS-3, and so on.

Base kV

Base kV for the bus. Note that the bus must have a kV entered before equipment can be connected to the bus. Anything less than 1 kV is considered low voltage, anything 1 kV or more is high voltage. MCCs and panel schedules can only be connected to low voltage buses.

For DC buses, see also DC Bus - Base Voltage Specifications.

Phase

The phase of the item. Currently, this is for reference only.

Lock Auto Sizing When this check box is selected, this item cannot be automatically sized using SmartDesign™ (the auto-design feature).
Upstream Rating

The minimum amp rating of equipment that is upstream from the bus (such as breakers, transformers, or cables). This information is for reference in certain specific configurations of EasyPower and is not generally visible.

Specifications Tab

Option Description
Bus Type

Type of equipment inside which the bus exists. The bus type definition is important for auto-design and arc flash hazard calculations. In arc flash hazard calculations, the parameters affected by type are the gap between conductors and the distance exponent. The various types are:

  • Switchgear: This can be low voltage or high voltage switchgear.
  • Open Air: The bus has no enclosures.
  • Conductor: Wire ways, bus ways, and so on.
  • MCC: Motor Control Center.
  • Panel: Small and lighting panels.
  • Panelboard: Low voltage power panelboards.
  • Switchboard: This can be a low voltage or high voltage switchboard.
  • NEMA E2 Contactor: NEMA E2 motor starter enclosures. The power voltage is at medium voltage. For low voltage control circuits this type can be used.
  • Int Switch: Interrupting or disconnect or safety switch.
  • VFD: Variable frequency drive or some type of motor drive.
  • UPS: Uninterruptible power supply.
  • ATS: Auto or manual transfer switch.
  • Transformer Terminal: Enclosure transformer terminals/bushings.
  • Vault: Underground space such as manhole for cable connections, transformers, and so on.
  • Padmount Equipment: Padmount switches, padmount transformers cabinets, and so on.
  • Control Panel: Enclosure for control circuits.
  • Junction Box – Large: Large or deep junction box.
  • Junction Box – Small: Small or shallow junction box.
  • Network Protector: Spot or grid network protectors used in network distribution systems.
  • Other: Any other type not specified.
Bus Rating
Mfr The manufacturer of the bus. User-defined, up to 15 characters.
Type The type of bus rating. User-defined, up to 15 characters.
Rating (A) Continuous current rating of the bus in amperes.
Bracing (kA)

Short circuit rating of bus bracing in kA. The testing standard unit is specified on the right as follows:

  • A high voltage bus can have asymmetrical kA or peak kA (crest) units.
  • A low voltage bus has symmetrical kA units.
Material
Material The material with which the bus is made. The options include copper, aluminum, or other.
Mounting The method by which the bus is mounted. Options include flush, surface, or free standing.
 
Area

Area numbers are used to uniquely define different areas of the electrical system. These areas can then be used for creating specific text reports from analysis operations that represent subsets of the system. For example, typical paper plant areas may be the power house (Area 1), caustic plant (Area 2), pulp mill (Area 3), and paper machine (Area 4). Area numbers are positive integers between 1 and 999.

Zone

A zone number is simply a sub-area. This enables even more specific reporting. You may want to define the pulp mill as Area 3 and the digester electrical equipment as Zone 2. Specific reports can then be generated for this combination without including the entire pulp mill or the other digesters.

One-line Graphics – Line Style The box drawn around the bus symbol in the one-line. Any line style can be selected from the box to represent an enclosure such as switchgear.
Device Code You can type letters or numbers to describe the device code for the equipment item. The information can be converted and printed as a QR code on arc flash labels.

Show Pad Symbol

When this option is selected, a rectangular pad symbol is displayed below the bus on the one-line.

Switchgear/Panelboard/Switchboard Tab

This tab allows you to calculate downstream loads on all the branches breakers connected to the bus. This tab can be labeled as Switchgear, or Panelboard, or Switchboard depending on the Bus Type selected in the Specifications tab.

Figure 2: Switchgear Tab of Bus Data Dialog Box

Option Description
Enable Switchgear Spreadsheet Selecting this check box enables you to modify information, enter load data and calculate downstream loads. Once you make the necessary data entry and calculations you can you can clear the check box to prevent changes. When the check box is not selected, the data can still be read, but not changed.
Calculate Downstream Load Clicking this button calculates all downstream loads for each breaker, fuse, or branch connected to this bus. All branches are considered downstream unless there exists a source such as a UPS, generator or utility in the direction of the branch. The program traverses through all the paths and determines whether or not there is a power source in the path. All loads are summed and reported in the spreadsheet if there is no power source in the path.

Results for Schedules

For the bus types ATS, switchgear, switchboard, panelboard, panel and MCC, you can fault buses and store the short circuit current and arc flash results in the database. These results can be displayed in schedules for switchgear, switchboard, panelboard, panels and MCCs. The stored results can also be viewed in the database browser and report. See Storing Short Circuit and Arc Flash Results for more information.

Unit You can display downstream loads in kVA or Amps.
Elevation You can choose the elevation layout of the switchgear such that protective devices in stacked in columns or rows. For columns, the breakers in one unit are stacked vertically. For rows, you can have a single breaker, or breakers on the left or right. See Elevation View for more information.
Diversity Enter the diversity factor for the bus. The factor is used in calculating connected, demand, code, and design kVA. The diversity factor is the ratio of the sum of the maximum demands of the individual loads to the maximum demand of the entire system, including all of those loads. Enter a value between 1 and 10.
Spreadsheet Column Headings
ID Name ID name of the equipment connected to the bus. If any branch has a protective device such as a switch, fuse or breaker connected to the bus, then the ID name of the protective device is shown. Otherwise the branch ID name is shown.
Section Space Text that describes the space for the protective device or branch.
Description Text that describes the branch connected to this bus.
Device You can specify the protective device or branch as Feeder, Main, or Tie. This is for information only and does not affect calculations.
Diversity

The number shown is the diversity factor of the downstream bus with an equipment type of Switchgear, Switchboard, or Panelboard. If another equipment type is selected, the diversity factor is set to 1. Diversity factor is used in calculating the connected, demand, code and design kVA. The diversity factor is the ratio of the sum of the maximum demands of the individual loads to the maximum demand of the entire system, include all of those loads. Click Calculate Downstream Load to update the diversity factor.

Device Rating (A) Continuous current rating of the protective devices in amps.
Cond Rating (A) Amp rating of branch conductors.
User Values Select the check box to manually enter a load. When checked, the entered values are used and the calculated downstream values from the one-line are ignored.

Equipment Elevation Tab

For information on this tab, see Elevation View.

Arc Flash Hazard Tab

The Arc Flash Hazard tab enables you to specify the necessary details of the equipment for arc-flash hazard calculations.

EasyPower calculates arc flash risk assessment results using the options set on the Arc Flash Hazard tab. The results are calculated for automatic transfer switches, buses, tool points of connection, MCCs, and panels.

Figure 3: Arc Flash Hazard Tab

Option Description
AF For This Bus

You can specify how you would like arc flash results determined for this bus using AF for this Bus.

Calculated: When the bus is faulted, EasyPower the performs arc flash hazard analysis using the calculation method specified in Short Circuit Options. EasyPower uses other settings on this tab as part of the calculations.

    Excluded: Select to exclude the bus from arc flash reports. An example of when you might select this option is for a bus that is required to model the electrical parameters of the system but does not actually represent a piece of electrical equipment. Other applications include nodes and tap-offs (junctions), where energized work is not required.

    Forced To: When you select this option, you can enter the incident energy and arc flash boundary for this bus. The incident energy and arc flash boundary values are shown on the one-line and in reports and work permits. This can be used for instances where you need to apply a calculation that is outside the scope of the industry standard calculations.

AF Output For This Bus

You can specify whether to display results on the line side or the load side of the Main protective device of the bus equipment. If the arc flash hazards output for this bus needs to be different from the global option, use this field. The choices are:

  • <<Use Global Option>>: Use the option specified in Short Circuit Options.
  • Including Main: Always display the arc flash hazard results on the load side of the Main protective device for this bus equipment regardless of what options are selected in the Short Circuit Options.
  • Excluding Main: Always display the arc flash hazard results on the line side of the Main protective device for this bus equipment regardless of what options are selected in the Short Circuit Options.
  • Both (Incl & Excl Main): Always display the arc flash hazard results on both the line side and the load side of the Main protective device for this bus equipment regardless of what options are selected in the Short Circuit Options.
Trip Times for this Bus

You can select the method for determining trip times for this bus by choosing from the following:

  • Pre-defined Fixed Times: Obtains arc clearing time for the bus from the library default values. This is not the same as the trip times calculated form the TCC curves of the upstream trip device. The values stored in the library are simply predefined approximate trip times. This is a legacy method and is not recommended.
  • User-defined Times: With this option you can specify the protective device clearing time for each bus. The details of arcing time for the bus can be specified in the fields Device ID, Relay Function and Time (s). When this option is selected, a time must be specified.
  • TCC Times (Automatically Calculated): Arc flash incident energy are calculated based on time characteristic current curves specified in each protective device data dialog box. The trip clearing time of the equipment where the device is a relay controlled breaker is the sum of the breaker mechanism opening time (for example, 3, 5, or 8 cycle), the relay trip time, and any time entered into the Relay Data, System, and Aux Time data fields.
  • User-defined and TCC Times: Provides results for both user-defined times and TCC times as described above.
  • User-defined One-line Device: With this option, you can specify which device you want to use for the TCC time, and the program will obtain the trip time automatically. You can select a device type (relay fuse, or low voltage breaker) and device ID. If you select a relay, you also select the relay function.
Working Distances

You can specify the working distances shown on the one-line and in reports and work permits.

  • Default from Options: When selected, the program uses the workings distances from the Default Working Distances spreadsheet in the Arc Flash Hazard Options.
  • User Specified: Selecting this option enables you to enter the working distance for this item.

The units displayed are based on the units selected in Arc Flash Hazard Options on the System tab. For inches, the range is 1-1000. For meters, the range is 0.1 to 1000.

Electrode Gap

You can specify the electrode gap shown on the one-line and in reports and work permits.

  • Default from Library: When selected, the program uses the electrode gap from the device library.
  • User Specified: Selecting this option enables you to enter the electrode gap for this item. The range is between 0.1 and 25,000 mm.

Electrode Configuration

You can specify the electrode configuration shown on the one-line and in reports and work permits.

  • Default from Library: When selected, the program uses the electrode configuration from the device library.
  • User Specified: Selecting this option enables you to select the electrode configuration for this item. The options available are based on the orientation of the electrodes, whether they are inside an enclosure, and in one instance, whether they terminate into a barrier.
  • Electrodes in Enclosures:

    • VCB: Vertical electrodes inside an enclosure.
    • VCBB: Vertical electrodes terminating in an insulating barrier inside an enclosure.
    • HCB: Horizontal electrodes inside an enclosure.

    Electrodes in Open Air:

    • VOA: Vertical electrodes in open air.
    • HOA: Horizontal electrodes in open air.

You can select more than one configuration to represent the multiple types of conditions that can occur for the equipment. EasyPower evaluates each configuration and then provides values for the highest incident energy based on the existing electrode configurations. Annex C in the IEEE 1584-2018 standard describes examples where you might use more than one electrode configuration.

Tip: To change the electrode configuration for multiple items on the one-line, select the items in the Database Edit focus and then on the Home tab, click Change > AF Bus Electrode Configuration.

Electrode configurations are only applicable to the IEEE 1584-2018 standard. For more information, see Electrode Configuration.

Enclosure Size

You can specify the enclosure size shown on the one-line and in reports and work permits.

  • Default from Library: When selected, the program uses the enclosure size from the device library. The library provides typical values based on the equipment type and voltage.
  • User Specified: Selecting this option enables you to enter the enclosure size for the item. This enables you to get more accurate calculation results, assuming the correct dimensions are entered.
  • The units displayed are based on the units selected in Arc Flash Hazard Options on the System tab. For inches, the range is .01-1000. For millimeters, the range is 0.1 to 25,000.

Labels to Print

Enter the number of labels you want to print for arc flash hazard analysis. If you enter "0," no labels will print.

Comment

You can type a comment that appears on the arc flash label when it is printed. For example, you could type a location description for the equipment to assist with label placement.

Accessories Tab

Figure 4: Accessories Tab

Option Description
Accessories Description The accessories for distribution equipment types can be specified in the panel, MCC, and bus dialog boxes. You can add or delete the accessory items as needed per equipment. Only the selected items are displayed in the schedule outputs.
Meter Data
Note An accessory note of up to 1,024 characters.
Maximum Demand The maximum demand load at this equipment.
Power Factor The power factor for the equipment.
Reading Date The date the meter was read or the information was gathered.
kVA
Safety Factor Percentage above the kVA that will be multiplied to calculate the new safety factor load.
Load with Safety Factor Load amount after calculating the safety factor.
Added (New) Demand Load User-specified load amount to add to the equipment.
Total New Demand Load Total of the load with safety factor and the added demand load.
Total Amps Amps based on the total demand load.

Change Management Tab

Note: This information is used in certain specific configurations of EasyPower and is not generally visible.

See Buses and Panels in Change Management Help for details.

Other Tabs

See Common Tabs for information on the Location, Comments, Hyperlinks, or Collected Data tabs.

More Information

Database Technical Reference Common Tabs
DC Bus - Base Voltage Specifications Electrode Configuration
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Help was last updated on 3/22/2019