Design Master Electrical and ElectroBIM can calculate and demonstrate compliance with the voltage drop requirements in the 2019 version of The Building Energy Efficiency Standards for California (commonly referred to as Title 24).

Section 130.5(c) states: “The maximum combined voltage drop on both installed feeder conductors and branch circuit conductors to the farthest connected load or outlet shall not exceed 5 percent.”
This requirement differs slightly from what is specified in NEC 210.19 Informational Note and NEC 215.2(A)(1) Informational Note No. 2. The NEC also recommends a total maximum of 5% for feeders and branch circuits, as well as a maximum value of 3% for the feeder or branch circuit separately.

Electrical for AutoCAD

Use the Insert Voltage Drop Schedule command to insert a schedule listing the feeder and branch circuit voltage drops in your project.

Set the Highlight Voltage Drops field to Yes, Feeder or Branch Circuit > 3%, Total > 5% to highlight any voltage drops that exceed the maximum values set by the NEC.

Set the Circuits to Display field to one of the following selections to display the voltage drop on all of the circuits on your panels:

• All: All circuits will be displayed, including spaces and spares.
• All with load: All circuits with a load will be displayed. Any circuits with a fixed load and no other devices connected will be displayed, but the voltage drop will be listed as 0%.
• All with voltage drop > 0: All circuits with a voltage drop greater than 0% will be displayed. Spaces and spares will not be listed, and circuits with fixed loads and no other devices connected will not be listed.

Use the Panels command to change the size of any feeders that exceed the maximum voltage drop.

Use the Circuiting command to change the size of any branch circuits that exceed the maximum voltage drop.

ElectroBIM

Use the Voltage Drop command to insert a schedule listing the feeder and branch circuit voltage drops in your project.

By default, feeder, branch circuit, and total voltage drops will be highlighted if they exceed the maximum values set by the NEC. To only highlight voltage drops that exceed the Title 24 maximum value, follow the steps below.

Select the FEEDER | VOLTAGE DROP column. Using the Modify Schedule/Quantities ribbon, set the shared parameter to DMET_VoltageDrop_Feeder_NoWarnings. Feeders that exceed the maximum value set by the NEC will not be highlighted.

Select the BRANCH CIRCUIT | MAX VOLTAGE DROP column and set the shared parameter to DMET_VoltageDrop_MaxCircuit_NoWarnings. Branch circuits that exceed the maximum value set by the NEC will not be highlighted.

Select the TOTAL VOLTAGE DROP column and set the shared parameter to DMET_VoltageDrop_Total to highlight any total voltage drops that exceed the maximum total values set by Title 24 and the NEC.

To reduce voltage drop totals that exceed 5%, use the Panel Edit command to change the size of feeders and the Circuit Edit command to change the size of branch circuits.