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Wire Ampacities

Allows you to create and modify wire ampacity configurations and wire sizing options.

Opens the Wire Ampacities dialog box:

Wire Ampacities Dialog Box​

Sizing Option Section​

Each row in the grid lists a sizing option. Each sizing option controls what is used when sizing wires automatically. In the Wire Ampacity section, which ☐ Standard, Branch Circuit, ☐ Standard, Equipment Circuit, and ☐ Standard, Feeder boxes are checked is based upon the active sizing option.

  •  Name ☰ The name of the sizing option.

  •  ☐ Active The sizing option that is active in the project. Branch circuit and feeders set to size automatically are sized based upon the selected sizing option.

    Only one sizing option at a time can be selected as the project default. Other sizing options can be selected for individual branch circuits and feeders.

  •   Creates a new sizing option.

  •   Creates a copy of the selected sizing option.

  •   Deletes the selected sizing option.

Wire Ampacity Section​

Each row in the grid lists a wire ampacity configuration. Each Breaker Trip value can have multiple configurations. One row for each Breaker Trip can be set as the default used when sizing branch circuits and feeders automatically. The other configurations can be chosen when sizing them manually.

  •  Breaker Trip The trip rating of the breaker.

  •  Wire Ampacity @ 30°C The ampacity of the wire at an ambient temperature of 30°C. This value is multiplied by the number of parallel runs to determine the final wire ampacity.

  •  Temperature Rating of Conductor ▾ The temperature rating of the phase wires.

  •  Description A label used to differentiate wire ampacities of the same size. The label will be displayed in other dialog boxes. It is not displayed in the schedules or on the plan.

    The combination of the Breaker Trip and Description fields must be unique for each row.

  •  Wire Size ▾ The size of the phase wires. The values in this field are based upon settings in the Wire Sizes command.

  •  Ground Wire Size, Service ▾ The size of the service ground. This sizing should be selected based upon NEC Table 250.102(C)(1).

    This wire size is used for the ground when the branch circuit device or distribution equipment is connected to a transformer. The values in this field are based upon settings in the Wire Sizes command.

  •  Ground Wire Size, Equipment ▾ The size of the equipment ground. This sizing should be selected based upon NEC Table 250.122.

    This wire size is used for the ground when the branch circuit device or distribution equipment is connected to anything except a transformer. The values in this field are based upon settings in the Wire Sizes command.

  •  Parallel Runs The number of parallel runs of conduits. Each run contains the same size wires.

  •  X The reactance for a single run of this size wire. See NEC Table 9 for values.

    This value is divided by the Parallel Runs value to determine the final reactance.

  •  R The resistance for a single run of this size wire. See NEC Table 9 for values.

    This value is divided by the Parallel Runs value to determine the final resistance.

  •  Conduit Type ▾ The conduit group that will be used when sizing the conduit. The values in this field are based upon settings in the Conduit Sizes command.

  •  ☐ Standard, Branch Circuit Whether the breaker size is used when sizing standard branch circuits.

    Only one breaker of each size can have this box checked. You do not need to have this box checked for each breaker. Breaker sizes that are not checked can still be selected manually.

  •  ☐ Standard, Equipment Circuit Whether the breaker size is used when sizing branch circuits based upon the MCA and MOCP of equipment connected to the circuits. Those criteria are set in the Family Edit or Instance Edit command for the connected equipment.

    Only one breaker of each size can have this box checked. You do not need to have this box checked for each breaker. Breaker sizes that are not checked can still be selected manually.

  •  ☐ Standard, Feeder Whether the wire ampacity is used when sizing feeders to distribution equipment.

    Only one wire ampacity of each size can have this box checked. You do not need to have this box checked for each wire ampacity. Wire ampacities and sizes that are not checked can still be selected manually.

  •   Creates a new breaker. The new row will use the same settings as the selected row when the button was pressed.

  •   Deletes the selected breaker.

  •   Moves the selected breaker up in the list. Use this button to sort wire ampacities with the same breaker size in the list. Breaker sizes cannot be moved out of numerical order.

  •   Moves the selected wire ampacity down in the list. Use this button to sort wire ampacities with the same breaker size in the list. Breaker sizes cannot be moved out of numerical order.