Wire Size

This portion of the dialog is used to create a table of wires to be used in the option.  You may create as many wire sizes as you need using the New Wire Size button. You may double-click on any row to re-type the wire size. 

Schedule Label

Wire Area

The wire area should be based on the outside diameter of the chosen wire type and its insulation.  This will be used in computing conduit fill. To edit a wire area, double-click on any row to re-type the wire area. 

Raceway Size

This portion of the dialog is used to create a table of raceways to be used in the option.  You may create as many wire sizes as you need using the New Raceway Size button. The size will appear on the plans as part of the home run wire callout, so chose a designation that matches your graphic standards. 

Raceway Area

The area should match the type of raceway for this option.  If the option includes EMT below 2” and RGS greater than 2”, then use the corresponding raceway areas.  This area will be used to compute raceway fill.  The default conduit fill maximum is 40 percent per the NEC.  If you wish a different criteria for this wire sizing option, then simply adjust the raceway area accordingly.  The area does not appear anywhere in Design Master other than this table, so it is not important what the table actually says.

Breakers and Conductors Field

Sets

This is the list of breakers and corresponding conductors that make up the standard list of feeders.  The table is organized by breaker size (or OCP size in the case where fuses are used).  This may not correspond exactly to the amp rating of the wire used, but DM default feeder selection is based on the OCP rating, and selection of the wires for each OCP size is defined in this table.  This allows for any variations on sizing you wish.  For example, the choice of 60C or 75C insulation rating is implied in the choice of wires for this table.

Amperage

This is the OCP size. Include each size that you may require for this sizing option. No fractional amps are allowed.

Wire size

This size should correspond to a wire size in the list of wire sizes. Note that it is a pulldown format that only allows selection of defined wires.

Service Ground

This is the size wire that you want for the feeder for a service ground.  This should be selected based on the NEC for service ground sizing.

Equipment Ground

This is the size wire that you want for the feeder for an equipment ground.  This applies to feeders and branch circuits.  This should be selected based on the NEC for equipment grounds.

Parallel Runs

This is the number of parallel runs of the conducts chosen to meet the amperage rating protected by the breaker size (OCP size).  For example, a 400 amp breaker might have (1) run of 500 kcmill copper or (2) runs of 3/0 copper depending on your preference for this option.  Note that the raceway selection is not included here since it is done automatically based on 40 percent conduit fill.

Impedance

This is the impedance of the feeder in ohms per 1000 feet phase to neutral divided by the number of runs.  This should take into consideration the type of wire and the type of raceway.  This impedance is used to compute fault and voltage drop.  For single phase circuits, this value is doubled to assume that the neutral is carrying the full current..

Is Standard

Check this box if this is a standard size you wish DM to use.  Otherwise, DM will use the next larger standard size and only a manual override will change this.  For example, 25 amp circuits might be included in the list, but not checked since this is a seldom used size.