electrical parameters: get results from electrical...

Electrical Parameters: Get Results from Electrical Families and Schedules Cassandra Watts – EELD

MP5160-V

Get a jump start on total control of your Autodesk® Revit®® MEP software project with parameters and calculated values. You will learn how to find the best answer for your family or schedule if you want your fixture families to have custom features or if you need your schedules to give you the answer to a more complex question. In this class, we will walk through how to choose the right parameter for the right job.

Learning Objectives At the end of this class, you will be able to:

• Insert and Edit Nested Families

• Create Visibility Controls for Individual Instances of a Nested Family

• Move Instances of Nested Families Manually Within a Project

• Generate and Use Mechanical Schedules for Use in the Electrical World

• Formulate Calculations in Revit® to Determine Electrical Information

About the Speaker Cassandra Watts is a drafter/designer for EELD where she is the lead BIM Designer. As well as working on several projects, she is in charge of research, development, and training in the Revit® software for the company

[email protected]

Electrical Parameters: Get Results from Electrical Families and Schedules

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Introduction Parameters are the tools of our Revit® world. They allow us to control elements and information, with constraints and controls, to more effectively create interactive spaces, and information. But if you don’t know how to input the right information into the parameters, Revit® can feel frustrating and limiting.

In this class we are going to focus on understanding just what parameters can do, by helping us to know what parameters to use, and when to use them. Whether you want to customize a family, or need a better way to create schedules, having correct parameters is the key to success.

Module 1 - Insert and Edit Nested Families In the first 3 modules of this class we are going to look at a complex track family that I built for a specific project for my company, and recreate the process. The finished product will be a track light fixture that allows the track head to face forwards, and backwards, as well as move side to side along the track, without moving the other track heads.

It’s a little bit of a process, but the finished product is great, and the principles can be applied to all of your electrical families in the future.

In a complex family, like the one we are going to create, we want to be able to make changes to different components in the family, as quickly and easily as possible, once the family is made. One of the best ways to ensure edits are easy, and accurate, is by using nested families.

A nested family is merely a regular family model, which has been loaded into another family model, instead of a project file. That model then becomes part of the final family when it is inserted into the project.

There are 2 major components in any track lighting system:

1. The track

2. The track head

In any regular track system family there is typically a track head family that has been nested into the track head family, so that it can be arrayed to represent all of the track heads on the fixture. This allows you to make edits to every track head at the same time.


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But the track system we are creating is no ordinary track system. Our track head is going to flip from facing forward to facing backwards while remaining at the same location on the track as it was before. In order to accomplish this objective we need to look at the possibilities, and what the ultimate outcome will be.

1. We can mirror the entire track head in the track head family

a. In this option all of the geometry is in one place which is nice, but it’s probable that if you edit one track head, you will need to delete the other and re-mirror it.

b. There are a few problems associated with this method. The main problem being that there is only one light source in the track head family. This means that if you need to render, or measure the light, it will not be an accurate representation. So let’s explore another possibility.

2. We can load the single track head family into a generic family, and mirror it there. (We won’t be going into depth about the photometric and light source information for the track head. Just know that it is contained in the original nested family.)

Option 2 will allow us to get some control over viewing and editing the family, which is what this class is all about. Let’s see how it works in practice…

Track Light - Exercise 1 of 4: Adding Visibility Parameters to the Nested Family Let’s take a look at what our nested “Track” family looks like in our generic family.

1. Open the “Track Head” Family from the class files

a. The base point head, which will attach to the track it’s self, is a small cylinder almost directly below the lamp. Because this is our “point of attachment” we want to make sure that it is also our center point.

b. I’ve aligned my track head, so that the center of the circle is the point at which both reference planes cross.

c. And the light has been mirrored across the vertical reference plane to ensure that the cylinder attachment of both lights is the exact same point.


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d. The bottom of the connector of both heads is exactly flush with the Ref. Level, as seen from the front view.

2. Add parameters to visibility

a. Select the head on the left

b. In the Properties Pallet click on the expansion box to the far right of the “Visible” option.

i. This will open an “Associate Family Parameter” Dialog box

c. Click “Add parameter” in the Associate Family Parameter dialog box

d. Call this parameter “Front” i. Family Parameter ii. Name: Front iii. Discipline: Common iv. Type of Parameter: Yes/No (Creates a check box control) v. Group Parameter Under: Visibility vi. In order to see and control these parameters once the family is loaded

into the “Track” family, any parameters in this family must be instance parameters.


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e. Click ok> and click OK in the Associate Family Parameter dialog box

f. The parameter for Visible is now grayed out when the track head on the left is selected.

g. Select the head on the right and follow the same process, except call this parameter “Back”.

3. Open the “Track” family from the class files folder

4. Load the “Track Head” family, into the “Track” Family

a. Place it anywhere along the track.

b. Center the Track head on the center of the track, and check to make sure that the bottom of the head (Or mounting point) lines up with the top of the track

5. Save and close the “Track Head” family.


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Module 2 – Creating Controls For Individual Instances of a Nested Family

When you want an instance of the nested family to act independently of the other instances of that nested family, use control parameters (For the sake of our exercise, visibility parameters), for each instance of the nested family in the family file. Once the family is loaded into a project, those parameters will give us flexibly and control over our family.

Track Light - Exercise 2 of 4: Creating Controls to Flip Each Instance of the Track Head In Exercise 1, we created visibility controls for the nested track head family. Now we will create several instances of the track head, and add controls and formulas to help us determine whether each head in our family faces forwards or backwards, once loaded into our family.

This first step is very similar to the visibility over rides in Exercise 1.

1. Select the track head 2. In the properties pallet, select the expansion box for the “Front” Parameter. 3. Add a parameter

a. Name: LT 1 F (Light #1 Front) b. Discipline: Common c. Type of Parameter: Yes/No d. Group Parameter Under: Other (You Won’t want to see it later) e. This parameter needs to be an “Instance” Parameter f. Click OK > and click OK

4. With the track head still selected, click the expansion box for the “Back” Parameter. a. Add a parameter b. Family Parameter c. Name: Flip 1 d. Discipline: Common e. Type of Parameter: Yes/No f. Group Parameter Under: Visibility g. This parameter also needs to be an “Instance” Parameter h. Click OK > and click OK

Don’t want to keep track of visibility parameters for each instance of the track head twice? Neither do I. Let’s tell Revit®, that the two heads should not be seen at the same time. We do this with a formula.

5. In the Properties Palette under the Modify Tab, click on (Family Types) to open the family types Dialog box.

6. Locate the two parameters just created (LT 1 F, and Flip 1) 7. In the Formula Box Under “LT 1 F”, type “Not (Flip 1)

a. This formula tells the “LT 1 F” parameter to turn off when the “Flip 1” is selected, and vice versa.


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Now let’s create the same visibility Parameters (IE: LT 1 F, and Flip 1) for each track head in our system. This may limit the number of track heads that you choose to have on in your track system. Determine how many heads you will typically need in this type of system, because each head will need to have its own set of parameters. Let’s stick with 9 heads for now.

8. Copy the Track head 9 times along the track – it doesn’t matter how far apart they are. 9. Follow the Previous Steps for “Creating Visibility Overrides for the Track Head” to create

the parameters for each of the nine heads. 10. The parameters for the “Front” heads will read as LT 2 F, LT 3 F, LT 4 F, etc. 11. The parameters for the “Back” heads will read as: Flip 2, Flip 3, Flip 4, etc. 12. Don’t forget to enter the Not (Flip #) Formulas for each of the LT # F Parameters.

This is what is should look like complete.

Try importing the track family into a project and flip each track head back and forth.


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Track Light - Exercise 3 of 4: Control the Number of Track Heads It is very unlikely that you will need exactly 9 track heads for every instance of track in your project. The following steps walk through how to create for the number of heads using parameters and formulas.

1. In the Properties Pallet click on the expansion box to the far right of the “visible” option, to open the Associate Family Parameter dialog box.

2. Click Add Parameter 3. Call the parameter “1 Light”

a. Family Parameter b. Name: 1 Light c. Discipline: Common d. Type of Parameter: Yes/No e. Group parameter under: Other f. I like to have my number of lights be a Type Property because it is easier for me

to control information, including notes, catalog number, tags and watts. i. You can assign this parameter as an instance parameter; just make sure

that the parameters for Voltage and Watts are also instance parameters, and remember to change the parameters accordingly for each instance in the project.

4. Repeat for each of the 9 track heads. Because checking every single light parameter to turn it on/off is a pretty tedious process, I decided to control the number of lights with an integer parameter. This parameter won’t change how the family works, and so is not necessary, but makes controlling the Types in the project, a little bit smoother.

5. In the Properties Palette under the Modify Tab > Click on (Family Types) to open the family types Dialog box.> Click Add, under Parameter.

a. Family Parameter b. Name: Number of Lights c. Discipline: Common d. Type of Parameter: Integer e. Group Parameter Under: Dimensions

i. I picked Dimensions because I want the Number of Lights grouped with the same information as the length of my track. You can also move the “Length” parameter to a different location – that is all preference.

f. Make this parameter either a type or instance parameter depending on how you assigned your “1 Light” – “9 Lights” parameters. In my case it’s going to be a Type parameter.


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Let’s have the track head visibility parameters, which we created previously, be controlled by the “Number of Lights” parameter that we’ve just made, by assigning a formula to the track head visibility parameters.

6. In the Properties Palette, under the Modify Tab> Click on (Family Types) to open the family types Dialog box.

7. Scroll down to the Track Head Visibility parameters (IE: 1 light, 2 Lights, ETC) 8. In the formula column next to “1 Light” enter “Number of Lights > 0”.

a. We are telling the parameters that in order for the visibility for “1 Light” to be on, the integer in “Number of Lights” has to be greater than 0(or 1 and higher).

9. Follow the same step for 2-9 lights a. 2 Lights will read “Number of Lights > 1” b. 3 Lights will read “Number of Lights > 2” and so on.

AWESOME! Now our visible instances are determined by one single parameter. And you never need to look at the 1-9 Lights parameters again. We are almost done, just one more step and you will have a really great track system that offers flexibility of design in your project.


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Module 3: Moving Nested Families Manually Within a Project. In a traditional track family the placement of the head along the track is controlled by one length parameter, which is spaced equally with all of the other lights. This is great when you don’t need to show what the head should be pointing at, but often in the lighting world we want and need to be able to show where on the track the head is located to insure that the correct painting, piece of furniture, or just right area is lit. And as a designer, I want to be able to manually move the track head.

Track Light - Exercise 4 of 4Exercis: Length Parameters, in all Their Glory.

1. Open the Ref. Level in the Track Family. 2. Draw a reference plane running horizontally next to Light 1

a. The reference plane will become our manual pull point for the light parameter. 3. Name it “Pull for light 1” and make it a weak reference 4. Align the reference plane with the center of the track head, and lock it in place so that

the track head and reference plane move together.

Hover over the center of the light

Align and Lock

5. Repeat with all 9 track heads

6. Draw separate dimension lines to the “pull” reference plane attached to each track head, starting from the track head in front of it, to control the distance between each head.


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a. Make sure that you are selecting the reference plane that we just locked into place, and not the reference line that exists in the nested family

Reference Line in nested family (WRONG)

Reference Line (Pull) locked to nested family (RIGHT)

b. The first track head will have a dimension line from the end of the track closest to it.

c. Make sure that they are separate dimension lines, as opposed to a solid run of dimensions, because each dimension needs to have its own parameter.

7. With the first dimension selected, > Click on the “Label” Drop-Down Menu at the top left

hand side of the screen. a. Select “Add Parameter…” b. In the Parameter Properties dialog box select the following options

i. Family Parameter ii. Name: Distance of L1 iii. Discipline: Common iv. Type of Parameter: Length v. Group Parameter Under: Other (I’m not going to use the actual

measurements very often) vi. This parameter needs to be an Instance parameter, or else you will not

have a pull in the project. 8. Repeat for each of the 9 dimension lines


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9. Make each Length parameter equal 14” so that your lights are evenly spaced when you place the family into your project.

10. Make sure that your “Number of Lights” parameter is set to show all 9 lights 11. Import your family into your project.

a. When you select the track light a little double arrow appears on each of the 9 track light heads. You can use these arrows to move the track light back and forth along the track.

12. With the track light fixture highlighted, select “Edit Type” 13. Change the “number of Lights” to 7, click ok

a. Even though the two track heads are no longer visible, the arrows to move them are.

b. As you move the track lights down the track, you will need to make sure that you do not cross any of the other track heads dimensions, or else your fixture will try to delete itself.

c. You can also change the distances to a precise distance in the instance parameter itself, under “other”.

That’s it! Now you have a fully functioning, highly controllable track light. Don’t forget that you can flip the heads around with the Flip parameters that we set up. Good luck!


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Module 4 – Mechanical Schedules for the Electrical World Electrical Engineers and Designers often create Mechanical Schedules for electrical drawings using Excel, or another spreadsheet programs because it allows us to incorporate formulas into a pre-made worksheet, which is able to do some of the calculations for us.

Revit® is designed to read and calculate schedules and other input. But out of the box it just isn’t able to give us the information that we need in order to create complex mechanical schedule information. In order have Revit® deliver the information that we want, we need to understand how to communicate to Revit® what information it needs to read, and how it should use that information. This tutorial will help you understand how to communicate the correct formulas to Revit® so that your schedule gives you the right information every time.

Mechanical Schedules Exercise1 of 3: Setting Up Mechanical Parameters Schedules which are generated in a database program, like excel, often use lookup tables to generate standard information. But because Revit® cannot directly import excel schedules, so we are left needing to either 1. Fill the information in manually to a premade schedule table, or 2. Import the excel table into AutoCAD and link the AutoCAD table into the Revit® project. Both options require extra time and maintenance, and neither utilized Revit®’s ability to store and read data.

Generating a Mechanical Schedule (For Reference) These steps are for your reference, in case you haven’t had a reason to set up this kind of schedule before, or haven’t done it in a while. I’ve already set the schedule up in the file, so don’t worry about setting this part up.

• Under the View Tab, in the Create Panel, > Select Schedules – Schedule/Quantities

• Scroll down to “Mechanical Equipment” • Rename the schedule “Mechanical Schedule” • Select the option of

“Schedule building components” • For phase “Complete” • Click OK. • In the next dialog box you will see a list of parameters.

a. Find electrical parameters for Voltage, Phase, and Wattage b. As well as “Mark”( which is how we are going to identify our equipment in our

drawings, and schedule), c. “Add” to the Scheduled Fields on the right. a. Move “Mark” is at the top of the list


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Working with the Mechanical Schedule 1. Open the “Mechanical Schedule Start” file from the class file downloads. 2. The mechanical schedule has the parameters for Voltage, Phase and Wattage loaded.

a. Because we are working with equipment from a third party, like the mechanical engineer, it is possible (or rather probable) the model, or family files come from several different sources.

b. Revit® will not be able to calculate the needed information from these conflicting parameters, so we are going to create some manual parameter or, project parameters, in our schedule.

c. Although there are different ways to add project parameters, we will be adding parameters directly in the mechanical schedule

3. In the Schedule Properties Dialog box >under the “Fields” tab click “Add Parameter…” a. All of the formulas in our schedule will be determined by Phase, Voltage, and

Wattage, so we’ll need to create project parameters for those. b. The Project parameters that we are creating will require us to manually input

information. In order to distinguish them from the actual parameter put “MECH” in front of the Parameter name.

4. The project parameter for Voltage will be MECH_VOLTAGE a. Discipline : Electrical b. Type: Electrical Potential c. Group: Electrical

(Personal Preference) d. The group can be anything that

will help you to locate and input the parameter later.

e. Make this a Type: Parameter (Personal preference)

i. Making this parameter a type parameter, will ensure that all equipment of the same type, has the same information for the project parameter, but may require you to make several types for one piece of equipment, that has several instances with different loads.

f. Check that the option to “Add to all elements in category” is selected

5. The project parameter for Wattage will be MECH_WATTS a. Discipline: Electrical b. Type: Apparent Power c. Group: Electrical (Personal Preference) d. This parameter will also be a Type parameter

i. If you made the MECH_VOLTAGE parameter an instance parameter, make this one an instance parameter as well.


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6. The project parameter for Voltage will be MECH_PHASE a. Discipline: Common b. Type: Integer c. Group: Electrical d. This Parameter will be an Instance Parameter (This will most likely effect your

later calculations, but we won’t be finishing them up here.)

NOTE: Make sure that your parameter names do not contain any numbers or symbols, including a dash, or else it will mess you up later. (Underscores are ok)

7. After you have finished calculating the MECH parameters, remove the Phase, Voltage, and Wattage parameters from the scheduled fields

a. Leave “Mark” there i. “Mark” is how I am identifying my equipment, in your drawing you may

choose a different parameter for identification, if this is the case, just replace “Mark”, with whatever your field is.

8. Once all of your parameters are in place click ok.

9. In the schedule, update the information for MECH_VOLTAGE, MECH_WATTAGE, and

MECH_PHASE. a. Because these are project parameters, they do not apply to the electrical

connector information used for circuiting. Always make sure that the information in your over rides and your family match.


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Module 5 – Calculating Values Using Formulas in Revit® Much like a look up table in Excel, you can program information into a Revit® schedule parameter. The main difference between the Excel and Revit® is that all of your information will be contained in a “Calculated Value” parameter, instead of a look up table… To be honest, the set up is a bit of a beast. The good news is; I’m going to walk you through how to form several of the calculations. And trust me, you’ll love this later! So put on your thinking cap, and hold on tight, this ride might get bumpy.

Understanding which parameters to create, and what information to use It is important that you understand how to get to the answer you are looking for step by step, so that you can make sure that all of the correct information is pulled. I used our existing lookup table, and my engineer for the information I needed, you may just need to write all of your equations down. Always remember to test your results. I like to put the information into my Excel data table, and Revit®, to make sure that they match up.

Using Calculated Values, and the information that we established in the last excise, we are going to tell Revit® just how we want it to get the information for each of the parameters in our schedule.

Calculated values could contain many different types of statements, we saw a few of those statements when creating the track lighting system. Most of the formula statements for this exercise, are going to be Conditional Statements ( IE: If/Then), In Revit® those statements are written as: IF (<condition>, <result-if-true>, <result-if-false>).

In the class files folder > in the Files for Mechanical Schedule folder, I’ve provided a PDF which shows an example of my company’s Excel schedule (top), as well as the finished product of my Revit® schedule. You can see that there are a lot formulas needed to determine all of the information for the schedule. We are not going to go in-depth into how to form each parameter, because you may form your parameters a little differently than I. But we will go through the steps necessary to find the Breaker Size, because that should be pretty standard, and hopefully give you a good idea of how to work these equations.

Mechanical Schedules Exercise 2 of 3: Calculating Amps We already have the wattage, voltage, and phase of the equipment, but before we can calculate the amperage, we need to tell Revit® how to find the square root of the phase.

AMPS = Watts/(Voltage*√Phase)

Equipment will either be Single Phase, or Three Phase. So the square root of the phase will either be √1=1, or √3=1.73

1. Open the practice project that we started in Module 4. 2. Navigate to the Mechanical Schedule that we created


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a. In the Project Browser > Schedules/Quantities>Mechanical Schedule. 3. In your Properties Pallet, click the “Edit” button next to the “Fields” option

a. This will open the Schedule Properties window. 4. Select the option “Calculated Value” 5. Name this Parameter SR Phase_hide

a. This is a parameter that you need in order for the future calculations to be correct, but it is not a number or parameter that you want to show in your final schedule, and will be hidden later.

b. There will be a few other parameters that are purely for the purpose of calculating another parameter, Just identify them so that you remember to hide them later in the project.

c. Remember to NEVER use any numbers, or mathematical symbols (like a “-“ or “#”) in the names of your parameters, or else your calculations will not function correctly.

6. This parameter is going to be a formula a. Discipline : Common b. Type: Number c. Next to formula, select the expand box

7. The 4 parameters that were created in the last excersize appear in the list. Any of these

four parameters may be used when calculating different values. 8. Select MECH_PHASE > Press ok. 9. In the formula box highlight, and copy MECH_PHASE

a. Our full formula, for any of our calculated values, has to be entered into this formula box. There is no limit for how long a formula can be (or at least I haven’t found one yet), but the box does not expand, which makes it nearly impossible to create a full formula (especially a complicated one), in the formula box.

b. Use a word processing tool like Notepad, (notepad is great, because it is a plain text editor) to create your formulas, and then copy/paste them into the formula box.

10. Open your text editor, on a new/blank page paste the MECH_PHASE. a. The reason that we select and copy the parameter name that we are using is so

that we can make sure that what our formula says matches perfectly, caps in all of the right places, with the way that we’ve named the parameter. If it does not match perfectly, the formula will not work.

11. The equation will look like this. if(MECH_PHASE = 1, 1, 1.73) a. Remember, we are telling it to look at the Parameter, so we have to make sure

that our parameter is written exactly as it is named (MECH_PHASE) parameter, or Revit® may not be able to calculate it.

12. Copy and paste the formula into the Formula box in Revit® 13. Click ok >Click ok in the Schedule Properties Dialog box 14. Make sure that your SR Phase_hide shows 1 for all of our single phase equipment, and

1.73 for our three phase equipment.


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Now that we have our base parameters taken care of, we can calculate our Amps.

15. Open the Schedule Properties Dialog box 16. Create a new calculated Value 17. Name this value AMPS

a. Formula b. Discipline: Common c. Type: Number d. This is not a conditional Format, but is very

similar. The formula should something like this:

i. MECH_WATTS/(MECH_VOLTAGE*SR Phase_hide) e. But, if you write it like that, you are going to get an error, because Watts and

Volts are two different parameter types, and therefore two different parameter units, which mean that they can’t be calculated.

Canceling out Units.

1. Divide the parameter by 1 of the unit. If you were to look at the parameters for the units you would see that the unit for Watts = w, and Volts = V

2. Here is what your formula looks like with your units canceled out a. (MECH_WATTS/1w)/((MECH_VOLTAGE/1v)*SR Phase_hide)

3. Copy and paste that into your formula box 4. Click ok>Click ok

I SUGGEST: Saving a copy of each of your formulas into a Mechanical Formulas folder, especially as they get more complex. That way if you need to make changes to the formula later, or make a new schedule, you have an easy to read record what each formula is. DO IT! You will thank me later.

Formatting the Schedule Parameters A few of the numbers for our calculated value of AMPS are pretty long, let’s format that parameter so that we don’t see all of the decimal points in our final schedule.

1. Open the Schedule Properties Dialog box 2. In the Formatting tab, select AMPS


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3. On the right hand side there are options to

change the Heading, the heading orientation, the alignment, and the field formatting.

4. Click Field Format… 5. Uncheck Use default settings. 6. Change units to “Fixed” 7. And change rounding to “2 decimal places” 8. Click OK

a. Before exiting out of the Schedule Properties, Highlight the SR Phase_hide parameter in that same Formatting window, and check “Hidden Field”.

9. Click OK

VIOLA!

PHEW!

We are almost there! The last two formulas were pretty short and simple. Calculating Breaker size is going to be a little trickier, because there are several variables.


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Mechanical Schedules Exercise 3 of 3: Calculating the Breaker Size

You probably know the breaker must be rated at 125% of the total AMPS for motors, so the calculated value for Breaker, has to do a few things.

1. Take our AMPS parameter, and multiply it by 125% (or 1.25) 2. Reference a list of Breaker sizes 3. and know which one to choose for every Amperage that we could have.

Let’s take this step by step, starting with how to multiply our AMPS by 1.25.

Revit® does that one pretty easily - it’s just (AMP * 1.25).

In Mechanical Schedules Exercise 2 of 3; we told Revit® how to determine if the square root of the phase was going to be 1 or 1.73, using an If/Then calculation. This parameter will have that similar If/Then formula.

1. Name this Parameter “BREAKER”. a. Discipline: Common b. Type: Number c. Because Amps can equal Breaker size, I’m going to tell my formula to look for

anything that is smaller than one AMP higher than my BREAKER. (IE: For a breaker size that is 20, the product of my (AMPS*1.25) can go all the way up to 21) So my equation will look something like this:

d. if((AMPS * 1.25) < 21, 20, 0) 2. Check it

a. Change EWH-1 from 4500 to 6000 and make sure that that the BREAKER size changes to “0”.

b. Change EWH-1 from 6000 to 5800 and see what happens. c. The breaker size changes back to 20, but if we check the AMPS we’ll notice a

problem. 3. The total of the (AMPS (in this case 16.12) * 1.25) is actually 20.15, which exceeds the

20 AMP breaker the formula is telling us, that we want to use. We can’t change the limit number (21) to 20 because then all of the AMPS that equal exactly 20 would be automatically bumped to a higher breaker than needed.

We need just the equation of AMPS*1.25 to round up, not the whole parameter, so using the formatting override for rounding up will not work in this case. The good news is that we can just add a “roundup” command to our equation instead. The equation will then read if(roundup(AMPS * 1.25) < 21, 20, 0)

4. Check to make sure that the EWH-1 says 0 for breaker.


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5. Find your list of breaker typical breaker sizes and continue on the calculation. a. Remember a conditional formula is: IF (<condition>, <result-if-true>, <result-if-

false>), You can add another equation as the “If false” option. b. Instead of saying if(roundup(AMPS * 1.25) < 21, 20, 0) your equation

should continue with the next breaker number. i. For breaker sizes 20, 25, and 30 my equation will read…

if(roundup(AMP * 1.25) < 21, 20,if(roundup(AMP * 1.25) < 26, 25,if(roundup(AMP * 1.25) < 31, 30, etc

1. Keep going until you have your whole list (the list I found online was to about 800).

TIP: This is where your Notepad comes really in handy. This is going to be a very long and complex calculation to enter in, and if you try to do it all in that little box you are going to curse my name, and give up.

6. Start with your first line of equation… if(roundup(AMP * 1.25) < 21, 20, 7. I found it easiest to have each breaker size on its own line when writing the equation.

Here is what my equation will look like when I’m done putting all of the information in.

The equation will end when the your answer is the last number possible (Like 800, in this equation)


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8. Revit® wants the equation to be all one line, however. So before copying and pasting the equation into Revit®, you will need to go through and make the equation one continuous line. This can be a little tricky and may require a couple of tries, so copy and paste the full set of equations below, so that you have a backup, in case you accidently delete something.

ONE MORE THING before pasting your equation into Revit®. Notice how we have used a series of parenthesis to separate out our equations… You need to close your long equation with the same amount of parenthesis as you started with. I count 26 Parentheses in my example above; you will need to have all 26 parentheses in your equation before Revit® will read it as a correct parameter. Often when a parameter has not worked for me in the past it is because I have too many or too few parentheses, always check that before you assume that your equation is wrong.

Now the breaker size is calculated for you. Play around with your wattages some more and see what happens.

Additional Examples of Complex Formulas for a Mechanical Schedule in Revit®. The breaker size is a good example of a complex formula, but there were a few more complex formulas that took me a while (and in some cases, a bit of help), to figure out just how to word. Here are a few examples of some of the other complex formulas to help you along.

General Wire Size

if(AMPS < 26, "12",

Because some of my wire sizes are 2/0, 3/0, and so on I’m going to run into Revit® trying to start a new equation with the / (divide) sign. This means, that in order to get my schedule to show me the correct answer, I have to do two things.

The above 12 in quotations (IE: “12”) Means that this parameter is a TEXT parameter, and that my answer will show up exactly as whatever I put between the quotation marks.

Because some of my equations depend on the “General wire size”, Namely the Conduit size, I’m going to create a second parameter called “General Wire_Hide”, which I will hide before my project is finished. That has the actual equation of “if(AMP < 26, 12,x” This parameter will be a Number parameter, and I will use it to reference with my Conduit size. Substitute 2/0 for 2.01 or something that you can keep track of.


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Conduit Size

if(and(Size of General Wire _Hide = 10, TOTAL NUMB WIRE= 3), "3/4 in",

Because the conduit size is dependent on both the General Wire Size, and the Number of Wires, and because there could be combinations of different Wire sizes, and number of wires, it is necessary for the equation for CONDUIT SIZE, to have an “and” provision.

In this first line example above you see that in order for the conduit size to be 3/4", the

General Wire size has to equal 10 AND the Total Number of wires has to equal 3, if not there needs to be another option… Etc. Notice also that because the answer is 3/4 in, the parameter will be a TEXT parameter. If you do not set it as a “TEXT” parameter, but have the quotations in the equation you will receive an “Inconsistent Units” notification. Make sure that they match up.

RKI Fuse Type (This is my really complicated one)

if(and(roundup(AMPS * 1.25) < 2, or(MECH_VOLTAGE = 208 V, MECH_VOLTAGE = 480 V)), "1",

This final example is a very compounded Text parameter. Because the you only need fuses when you have a disconnect, this parameter will only apply to equipment that is 208 or 480 Volt. So by saying “or(MECH_VOLTAGE = 208 V, MECH_VOLTAGE = 480 V)” We are telling Revit®that to look for either 208 V or 480 V.


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But the fuse, much like the breaker, needs to be account for 125% of the Amp draw, which we saw in our Breaker calculation is found with the (roundup (Amps*1.25)… formula. In order to make sure the Revit®is looking for both the Amps requirement and the Voltage requirements you need to give it an “And” provision.

Also similarly to the breaker size, the load on the fuse, will be less than or equal to the size of the fuse, which to Revit®just means anything smaller than one number higher than the fuse.

So you end up with:

if(and(roundup(AMPS * 1.25) < 2, or(MECH_VOLTAGE = 208 V, MECH_VOLTAGE = 480 V)), "1",

You’ll notice that in the portion of my list that you can see there are no fractions which means no “/” (divide) signs. So why is this parameter a text parameter? Because at the end of my list, when I’ve reached my limit, I’m giving my field an “Error” message, so I needed to enable text. You may handle it differently, and may be able to keep it a number parameter.

I hope this helps you feel a little more confident as you move forward to create your own Mechanical Schedule in Revit, and that you will be able to form your parameters with more ease, understanding how Revit® reads the information that you need.

Thanks for checking out the class, and keep building in the world of Revit®.

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