When customizing wire sizes in Design Master Electrical, it is possible to create “Sizing Options.” The option controls which wire configurations are used by default for different size breakers. It does not change the list of wire sizes, conduit sizes, or breaker sizes that are available. It is only possible to have one option active for a project.

Default Breaker Sizes

In the breaker grid at the bottom of the “Wire Sizing” dialog, there are three check boxes related to default breaker sizes:

• Standard Branch Circuit
• Equipment Branch Circuit
• Standard Feeder

You can specify one of them as each of these defaults for each size breaker. For example, you can have all three defaults use the same breaker:

Or have all the defaults use a different breaker:

Or not use the size as a default breaker. In this situation, the breaker sizes are options when manually sizing breakers and wires, but will never be automatically chosen by the software:

Standard Branch Circuit

The breakers specified as standard branch circuits are used when sizing branch circuits connected to receptacles, light fixtures, and equipment connections. The smallest standard breaker is used to size the branch circuit. Typically, uncommon breaker sizes such as 15A and 25A are not specified as standard branch circuits. This setting allows you to use them in your project when necessary, but not size to them automatically.

Equipment Branch Circuit

The breakers specified as equipment branch circuits are used when sizing equipment automatically using MCA and MOCP. For equipment, you typically want to size to uncommon breakers such as 15A and 25A when that is what the MOCP calls for.

Standard Feeder

The breakers specified as standard feeders are used when sizing wires between distribution equipment.