Work with electrical circuit paths and wire sizing

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When working with electrical circuits in rev.

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It,

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it's important to understand how circuit lengths and wire sizes are determined.

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In this project, we will consider the settings and values used to establish both.

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Then by reviewing circuit properties and calculated values in a schedule,

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we will monitor changes to voltage drop,

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circuit length and wire size

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information that can be used to check.

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We are conforming to design requirements and to drive change in a project

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within the electrical settings of rev is the option to

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define the maximum voltage drop for branch and feeder circuits.

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The values can be altered to suit the installation.

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For example, if it's a private or public supply

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and are set by default at 2% and 3% respectively.

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If the voltage drop for a circuit exceeds the defined values,

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the calculated wire size for that circuit will be automatically increased.

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Voltage drop values can be displayed in panel schedules and in the system browser.

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But to monitor the circuits in a project more closely and to

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understand how near to the maximum voltage drop each circuit is,

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it can be advantageous to create an electrical circuit schedule

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from the view tab create a new electrical circuit schedule

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and name it branch circuit.

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Then at the following fields,

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circuit number

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length,

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voltage

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and voltage drop

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from the filter tab filter by voltage values that equal 120 volts

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then select ok. To finish the schedule,

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you'll see from the schedule that the voltage drop value is measured in volts

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rather than as a percentage as defined in the electrical settings as such.

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It's not immediately obvious how close to

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the maximum allowable value each circuit is.

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So let's go ahead and display the value as a

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percentage by creating a calculated field in the schedule.

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Select the edit button against fields in the properties window,

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then add a calculated parameter,

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call it percentage voltage drop.

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Leave the discipline and type options and enter the following formula.

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Voltage drop

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divided by voltage

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multiplied by 100.

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It's now clear to see

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all of the branch circuits are within the maximum allowable

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voltage drop of 2% with the current wire size.

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Open the view one lighting and use the tab key and

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the left mouse button to highlight and select the hallway circuit.

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Then review the wire size in the properties.

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This status can change due to additional loads. And if the circuit path is altered,

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use tile windows to display the floor plan and the schedule

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start by seeing how much the voltage drop is

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affected by adding more lighting fixtures to circuit three,

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edit the circuit

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and add the lighting fixtures from the room in

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the bottom left corner of the floor plan,

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a review of the calculated value shows the

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voltage drop has increased from approximately naught 0.8%

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to 1.2%.

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And the circuit properties show the wire size is the same.

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The default electrical circuit length is calculated using

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the device furthest from the point of distribution.

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But this can be edited to include all devices

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which will of course increase the length of the circuit

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and affect the voltage drop value.

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Select the hallway circuit again and choose edit path from the ribbon

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from the path mode, dropdown menu change the option to all devices

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and note the change to the voltage drop in the schedule which is now at 1.8%.

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And with the wire size remaining the same

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next

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increase the path offset value to 10 ft

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and review the values of voltage drop

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and wire size.

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Finish editing the circuit path,

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finally

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edit the hallway circuit one last time,

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then add a lighting fixture from any other circuit

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by exceeding the maximum voltage drop of 2%. For this branch circuit.

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The wire size has increased

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and the voltage drop reduced

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providing the appropriate voltage drop values in the electrical settings.

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And editing circuit paths provides invaluable feedback.

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When creating and editing circuits

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as circuit links and loads increase,

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we can use the feedback from the circuit properties and

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from schedules to monitor voltage drop and wire size,

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we can understand at what point rev,

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it will automatically increase wire size and if necessary

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alter our design to meet the required specifications.