Conduit / Conductor Calculator Tool - Review

[Koosha_engX]

Hi All,

So, myself and a friend have been working on a site, which will include various engineering calcs. Currently, the conductor / conduit sizing tool is up and running (there are two calculators, which can be toggled between from the top of the page). I would appreciate any feedback. You can check it out in the following link; keep in mind though, it's a work in progress: http://engcalc.herokuapp.com

Please review with the below points in mind; any and all constructive criticism is welcome.

1) How does the calculator work for you; does it help you with your work?

2) Is anything confusing that may need to be better explained / clarified (e.g. naming, user interface, etc.)?

3) What other feature would you like added into the flow (e.g. voltage drop)?

4) Is anything wrong / inaccurate?

5) Any other calculators that you're interested to have automated?


Again, your feedback will tremendously help. Thanks in advance.

Disclaimer: please don't use this tool right now for your work, as there still may be some issues that need to be ironed out.

 

[Koosha_engX]

Does anyone have any feedback or anything they would like to see added? Any and all comments are welcome and would be appreciated

 

[kwired]

conduit fill calculator seems ok, presuming it is accurate.

the other one, don't think user should need to enter both conductor temp rating and conductor type, entering conductor type should automatically tell the application what the temp rating is.

also I entered a FLA of 19 amps, 90 deg conductor, 3 current carrying, 30 deg ambient

results said I can use 14 AWG conductor, but needed a 12 AWG equipment ground, didn't double check accuracy on fill.

Most cases you would need to multiply FLA x 1.25, and min ampacity would be based on 75C ampacity column even if using 90C conductor.

To figure EGC size one needs to at least know what the setting of overcurrent device is and then go to table 250.122 to select minimum size EGC. EGC would never need to be larger then the largest ungrounded conductor though.

That first 19 amp example was just a random number.

I then tried to enter data as would be required to determine minimum conductor size for a 3 phase 480 volt 100 hp motor.

NEC requires to use 124 as FLA for this motor, again I went with 90C conductor, and 3 current carrying conductors. Application result said to use 2 AWG conductor, 6 AWG EGC. 124 A x 1.25 = 155. 75C terminations would require 2/0 AWG conductor, pretty significant difference in size there. 6 AWG EGC is normally fine, but if the OCPD would happen to be over 200 amps it would need to be 4 AWG.

 

[Koosha_engX]

To preface, I really appreciate your thorough response. Really helps, especially as small details can so easily slip through the cracks.

conduit fill calculator seems ok, presuming it is accurate.

Was the conduit fill calculator straightforward for you; anything extra you would like to see added?

the other one, don't think user should need to enter both conductor temp rating and conductor type, entering conductor type should automatically tell the application what the temp rating is.

We have included the input for both "temp rating" and "conductor type", because some conductor types are referenced in both columns and have different ampacity ratings in Table 310.16. Example: RHH has a rating of 50A for #8 AWG in the 75C column, and 55A rating for again #8 AWG in the 90C column. I will revisit this below, as you made a valid point.

Most cases you would need to multiply FLA x 1.25, and min ampacity would be based on 75C ampacity column even if using 90C conductor.

Using the "AC Motor Load Calculator" in the program, the calculated FLA is multiplied by 1.25 on the backend of the program (when the program uses equations to solve for the FLA). This calculated FLA is then carried over to the "Conductor & Conduit Parameters" portion of the program for conductor sizing.

So this ties back to what you were stating earlier, on omitting the "temp rating" or "conductor type". Now, since the user has the option of simply always selecting 75C, should we leave the program as is, even though in the real world, the 75C column would most always be used? This gives the user greater flexibility. Thoughts?

To figure EGC size one needs to at least know what the setting of overcurrent device is and then go to table 250.122 to select minimum size EGC. EGC would never need to be larger then the largest ungrounded conductor though.

Great point regarding the EGC size. Currently, the EGC size is being calculated using the FLA. Simply, comparing the outputted FLA to the Ampere column shown in Table 250.122.

Per your comment, what do you think of the following suggestion: the program would output a suggested protective device rating using table 240.6(A), per our outputted FLA. This output would appear in the "Conductor & Conduit Parameters", and the user can change this suggested protective device rating value if they so desire. Thereafter, in the final program output, the ECG will be sized per the protective device setting.

Example: if the FLA is 37 (with 1.25 multiplied in), the program would suggest a 40A breaker. Then, if the user does not change the 40A breaker rating, the final output of the program would be a #10 AWG Cu. GRD.

I then tried to enter data as would be required to determine minimum conductor size for a 3 phase 480 volt 100 hp motor.

You caught a mistake here. I see the problem. In the program, when the user selects "Use NEC Lookup Tables" (where the program pulls the FLA value from Table 430.247 thru Table 430.250), the FLA is then not multiplied by 1.25. Currently, only when the "Use NEC Lookup Tables" is not checked, and the program uses equations to solve for the FLA, the 1.25 is multiplied in (as I referenced earlier).

Going back to our same question again: you said you selected 90C, but should we (the program) always revert back to using the 75C column? Should this be blanketed across all sizing scenarios? My concern is restricting a user again, being they have the option to always select 75C to begin with.


Thanks again - very helpful comments!

***I'm not sure how to properly quote your response as you can see. It's not showing your name. I'm still learning***

 

[kwired]

Was the conduit fill calculator straightforward for you; anything extra you would like to see added?

Pretty straight forward. Only thing to add may possibly be ampacity selection and adjustment features, this would require input of load, ambient temp, circuit details such as number of current carrying conductors, possibly the ability to determine if a neutral is current carrying or not for ampacity adjustment reasons

We have included the input for both "temp rating" and "conductor type", because some conductor types are referenced in both columns and have different ampacity ratings in Table 310.16. Example: RHH has a rating of 50A for #8 AWG in the 75C column, and 55A rating for again #8 AWG in the 90C column. I will revisit this below, as you made a valid point.

I don't see any conductor types in more then one column other then RHH will be in 90C column for copper as well as in 90C column for aluminum. Speaking of aluminum doesn't look like you have included aluminum conductors in the application.

Using the "AC Motor Load Calculator" in the program, the calculated FLA is multiplied by 1.25 on the backend of the program (when the program uses equations to solve for the FLA). This calculated FLA is then carried over to the "Conductor & Conduit Parameters" portion of the program for conductor sizing.

So this ties back to what you were stating earlier, on omitting the "temp rating" or "conductor type". Now, since the user has the option of simply always selecting 75C, should we leave the program as is, even though in the real world, the 75C column would most always be used? This gives the user greater flexibility. Thoughts?

Didn't notice the AC motor load calculator the first time using, tried 100 HP motor again and still only came up with needing a 1 AWG conductor when it should have been 2/0. In real world conductors almost always need to be no smaller then 75C column because terminations are only rated 75C, but you can still use 90C column as a starting point for any ampacity adjustments for number of conductors in raceway or ambient temp adjustments. If minimum conductor needed after ampacity adjustments is larger then minimum needed for termination rating then you use the larger conductor, if termination rating yields larger conductor you must still use that conductor size as a minimum.

Great point regarding the EGC size. Currently, the EGC size is being calculated using the FLA. Simply, comparing the outputted FLA to the Ampere column shown in Table 250.122.

EGC size is difficult to determine if you don't determine what the overcurrent protection will be. NEC allows 175% of FLA for time delay fuses and 250% for inverse time breakers, and if that doesn't allow starting of the motor you can increase it. Many fuse and breaker manufacturers charts will recommend lesser then 175% or 250% for those applications though. Square D calculators recommend 175 amp fuses or 200 amp breaker for the 100 hp 480 volt motor. Both would permit 6 AWG EGC. If you go with NEC and 175 or 250% values 6 AWG is not large enough for the EGC.

Per your comment, what do you think of the following suggestion: the program would output a suggested protective device rating using table 240.6(A), per our outputted FLA. This output would appear in the "Conductor & Conduit Parameters", and the user can change this suggested protective device rating value if they so desire. Thereafter, in the final program output, the ECG will be sized per the protective device setting.

Example: if the FLA is 37 (with 1.25 multiplied in), the program would suggest a 40A breaker. Then, if the user does not change the 40A breaker rating, the final output of the program would be a #10 AWG Cu. GRD.

Several factors can come in to play here also. If the 37 amp load is resistance heating a 40 amp breaker is just fine. If the 37 amp load is a motor, it could easily have up to an 80 amp inverse time breaker and be NEC compliant. If that don't allow the motor to start it can still be increased some.

The next wrench in the gears with the EGC is if there is any increase in ungrounded conductor sizes for things like voltage drop - then the EGC must be proportionally increased in size.

Is difficult to cover all possibilities, but not impossible, just depends on what you want to put into your application or what you want it to do.

Going back to our same question again: you said you selected 90C, but should we (the program) always revert back to using the 75C column? Should this be blanketed across all sizing scenarios? My concern is restricting a user again, being they have the option to always select 75C to begin with.

As I already mentioned most of the time conductors can not be any smaller then the 75C column because terminations on almost all 600 volt and less equipment will never be 90C, nearly all terminations today will be 75C, some older equipment (like over 35 -40 years old) may only have 60C termination rating.

Thanks again - very helpful comments!

***I'm not sure how to properly quote your response as you can see. It's not showing your name. I'm still learning***

You are welcome.

Kind of a pain to make it include name and link to the post unless you are quoting the entire post with the "reply with quote" button near bottom right of the reading pane. What you (and I) did to break things up and reply to each element is about the easiest way to do it.

 

[lakecitieselectric]

Hi All,

So, myself and a friend have been working on a site, which will include various engineering calcs. Currently, the conductor / conduit sizing tool is up and running (there are two calculators, which can be toggled between from the top of the page). I would appreciate any feedback. You can check it out in the following link; keep in mind though, it's a work in progress: http://engcalc.herokuapp.com

Please review with the below points in mind; any and all constructive criticism is welcome.

1) How does the calculator work for you; does it help you with your work?

2) Is anything confusing that may need to be better explained / clarified (e.g. naming, user interface, etc.)?

3) What other feature would you like added into the flow (e.g. voltage drop)?

4) Is anything wrong / inaccurate?

5) Any other calculators that you're interested to have automated?


Again, your feedback will tremendously help. Thanks in advance.

Disclaimer: please don't use this tool right now for your work, as there still may be some issues that need to be ironed out.

If I could upload a XLS on here I would share a old spreadsheet I got from a friend that is pretty cool and has all these calculations. Its out dated and needs to be redone.

 

[Koosha_engX]

Pretty straight forward. Only thing to add may possibly be ampacity selection and adjustment features, this would require input of load, ambient temp, circuit details such as number of current carrying conductors, possibly the ability to determine if a neutral is current carrying or not for ampacity adjustment reasons

Noted. I will need to think this over design wise, as the user interface would become cluttered. The simplicity of one row for each conductor would be lost. For this specific tool, my assumption was the user already knows the conductors they will place inside of the conduit.

Great input though for an advanced supplemental feature to later add.

Didn't notice the AC motor load calculator the first time using, tried 100 HP motor again and still only came up with needing a 1 AWG conductor when it should have been 2/0.

Yes, there seems to be a problem on the backend of the program. I need to revisit the calculation for the motors. Curious, what power factor value did you input into the calculator?

I don't see any conductor types in more then one column other then RHH will be in 90C column for copper as well as in 90C column for aluminum. Speaking of aluminum doesn't look like you have included aluminum conductors in the application.

My mistake with the RHH reference. It's actually THHW and XHHW that cross over between 75C and 90C (as seen in the image below). And thanks for pointing out Aluminum. Noted to be added.



Regarding the 75C column: let me ask this then; if we are to always err on the side of caution (be more conservative), would it be more prudent for us to simply remove this 90C column from the tool from your perspective? At this stage, I'm not even sure in what scenario someone would even use the 90C column then?

EGC size is difficult to determine if you don't determine what the overcurrent protection will be. NEC allows 175% of FLA for time delay fuses and 250% for inverse time breakers, and if that doesn't allow starting of the motor you can increase it. Many fuse and breaker manufacturers charts will recommend lesser then 175% or 250% for those applications though. Square D calculators recommend 175 amp fuses or 200 amp breaker for the 100 hp 480 volt motor. Both would permit 6 AWG EGC. If you go with NEC and 175 or 250% values 6 AWG is not large enough for the EGC.

Great point! This becomes a little tricky then without added increased functionality for the user. What I am thinking is to give the user both the 175% time delay fuse and 250% inverse time breaker option output, and thereafter, the user can edit this figure if they desire. This will allow for greater accuracy with the selection of the EGC as you stated.

Several factors can come in to play here also. If the 37 amp load is resistance heating a 40 amp breaker is just fine. If the 37 amp load is a motor, it could easily have up to an 80 amp inverse time breaker and be NEC compliant. If that don't allow the motor to start it can still be increased some.

The next wrench in the gears with the EGC is if there is any increase in ungrounded conductor sizes for things like voltage drop - then the EGC must be proportionally increased in size.

Is difficult to cover all possibilities, but not impossible, just depends on what you want to put into your application or what you want it to do.

Great coverage of points with the ECG. It seems I will need the following

• A toggle option between the load type for the user from the get go (e.g. resistive, motor, etc.)
• The protective device output choice as I mentioned above. I would output per the NEC (the 175% and 250% for respective devices), yet allow the user to still edit this figure (as some motors may still need an increase as you mentioned).
• It seems I'd need to incorporate a voltage drop calculator into the mix for increased accuracy for both the ECG and current carrying conductors themselves. More real world utility would be granted.

My goal here is to provide a tool that is accurate, yet very easy to use for anyone. Hence, the importance of the UI (User Interface).

As I already mentioned most of the time conductors can not be any smaller then the 75C column because terminations on almost all 600 volt and less equipment will never be 90C, nearly all terminations today will be 75C, some older equipment (like over 35 -40 years old) may only have 60C termination rating.

We addressed this above. Thank you for the great point.

Kind of a pain to make it include name and link to the post unless you are quoting the entire post with the "reply with quote" button near bottom right of the reading pane. What you (and I) did to break things up and reply to each element is about the easiest way to do it.

That's good to know, as I was fiddling around for a good while, trying to figure out how to properly quote.

Side question: outside of this conductor / conduit sizing, is there any other calculator / tool you would find useful, to be automated? Whether from the NEC or elsewhere. The goal is to make things simple, beautiful (UI wise), and of course, accurate and helpful. Can be anything.

 

[Koosha_engX]

If I could upload a XLS on here I would share a old spreadsheet I got from a friend that is pretty cool and has all these calculations. Its out dated and needs to be redone.

That would be great! I'm new to the forums, so I'm not sure if such attachments can be made. Out of curiosity, what functionality does the Excel sheet have / serve?


By the way, on these forums, can we reference / call-out other users? Example: on social media platforms, if you use the '@' symbol, you will call another user (e.g. @lakecitieselectric).

 

[lakecitieselectric]

That would be great! I'm new to the forums, so I'm not sure if such attachments can be made. Out of curiosity, what functionality does the Excel sheet have / serve?


By the way, on these forums, can we reference / call-out other users? Example: on social media platforms, if you use the '@' symbol, you will call another user (e.g. @lakecitieselectric).

PM your email

 

[lakecitieselectric]

That would be great! I'm new to the forums, so I'm not sure if such attachments can be made. Out of curiosity, what functionality does the Excel sheet have / serve?


By the way, on these forums, can we reference / call-out other users? Example: on social media platforms, if you use the '@' symbol, you will call another user (e.g. @lakecitieselectric).

Okay, I sent them to you. Let me know what you think.

 

[Koosha_engX]

Okay, I sent them to you. Let me know what you think.

I appreciate you sending over the Excel sheets. Great reference. I had a chance to go through them, and below are my initial 3 questions, to get your insight.

1) I'm not too familiar; is the CORROSION TAPE CALCULATOR and ARC PROOF TAPE CALCULATOR, solving for the width of the roll and number of rolls, a common calculation made? Do you use this often yourself?

2) Do you think a Residential Calculator is helpful to have, for load calcs; calculating demand for appliances, thereafter sizing breakers and panels?

I do believe a load calculator for all voltage ratings would be helpful (e.g. calculating a service size or panel rating), whether for residential, water / wastewater treatment plants, industrial facilities, etc. However, I think these types of calculators are common, unless you have experienced any shortcomings with any of them. If yes, please let me know.

3) Are there any other calculators / tools that you think would be of good use to you or anyone, or simply something that needs a better interface / update? Doesn't necessarily need to be electrical related.


Furthermore, regarding the WIRE FILL CALCULATOR in your Excel sheet:
It is similar to our: engcalc.herokuapp.com/#custom-conduit-fill but without the custom conductor feature we have. Plus, we have added the option where you can easily add endless wires via the "Add Row" feature.



When you select "Other / Custom", you can enter in your own custom wire area for in the conduit. Imagine if you had 1 fiber optic cable, and the spec sheet listed the area as 0.747" squared.

The other calculators from your sheets, outside of the LIGHTING ROI CALCULATOR, we will need to infuse into http://engcalc.herokuapp.com/#standard-conduit-calculator per my discussion with kwired, if they do not already exist to some capacity.

 

[kwired]

Noted. I will need to think this over design wise, as the user interface would become cluttered. The simplicity of one row for each conductor would be lost. For this specific tool, my assumption was the user already knows the conductors they will place inside of the conduit.

Great input though for an advanced supplemental feature to later add.


Yes, there seems to be a problem on the backend of the program. I need to revisit the calculation for the motors. Curious, what power factor value did you input into the calculator?

View attachment 17545


My mistake with the RHH reference. It's actually THHW and XHHW that cross over between 75C and 90C (as seen in the image below). And thanks for pointing out Aluminum. Noted to be added.

View attachment 17544

Regarding the 75C column: let me ask this then; if we are to always err on the side of caution (be more conservative), would it be more prudent for us to simply remove this 90C column from the tool from your perspective? At this stage, I'm not even sure in what scenario someone would even use the 90C column then?


Great point! This becomes a little tricky then without added increased functionality for the user. What I am thinking is to give the user both the 175% time delay fuse and 250% inverse time breaker option output, and thereafter, the user can edit this figure if they desire. This will allow for greater accuracy with the selection of the EGC as you stated.



Great coverage of points with the ECG. It seems I will need the following

• A toggle option between the load type for the user from the get go (e.g. resistive, motor, etc.)
• The protective device output choice as I mentioned above. I would output per the NEC (the 175% and 250% for respective devices), yet allow the user to still edit this figure (as some motors may still need an increase as you mentioned).
• It seems I'd need to incorporate a voltage drop calculator into the mix for increased accuracy for both the ECG and current carrying conductors themselves. More real world utility would be granted.

My goal here is to provide a tool that is accurate, yet very easy to use for anyone. Hence, the importance of the UI (User Interface).


We addressed this above. Thank you for the great point.


That's good to know, as I was fiddling around for a good while, trying to figure out how to properly quote.

Side question: outside of this conductor / conduit sizing, is there any other calculator / tool you would find useful, to be automated? Whether from the NEC or elsewhere. The goal is to make things simple, beautiful (UI wise), and of course, accurate and helpful. Can be anything.

The calcultor would not let me change power factor or motor efficiency when I was using it. They were both at 100%.

The other thing about this though is when selecting conductor ampacity per NEC, you don't even look at power factor or efficiency, you use values from motor full load tables near the end of art 430. Those apparently take the worst possible power factor and efficiency for each motor listed, as you almost never see one that draws what the table says, but we are still supposed to select conductor ampacity based on the tables. If your calculator figured 100% power factor and 100% efficiency that may be why it came up with too small of a conductor even though it supposedly did figure as 125% of FLA.

I have no idea why THHW and XHHW are in both 75 and 90C columns in 310.15(16) They both shoudld be 90C conductors AFAIK.

You said not sure what scenario one would use 90C column -- it is used for ampacity adjustments. You must always have a conductor that meets the termination rating (these days usually 75 C, but with some older equipment it could have 60C terminations, and if using NM cable you always use 60C for termination temp, but can still make adjustments (for number of conductors in raceway or ambient temperature) from 90C ampacity if it has 90C insulation. You basically have to figure out the 75C ampacity, then figure the 90C ampacity and select whichever conductor is larger. If there is no adjustments, the 75C conductor will always be larger. If adjustment factors used are ~70% or higher usually the 75C conductor is still the larger conductor. More then 9 current carrying conductors in raceway will make you increase conductor size most of the time over what you would have if 9 or less conductors. Ambient temp and number of conductors can sometimes add up the adjustment pretty fast.

 

[Koosha_engX]

The calcultor would not let me change power factor or motor efficiency when I was using it. They were both at 100%.

The other thing about this though is when selecting conductor ampacity per NEC, you don't even look at power factor or efficiency, you use values from motor full load tables near the end of art 430. Those apparently take the worst possible power factor and efficiency for each motor listed, as you almost never see one that draws what the table says, but we are still supposed to select conductor ampacity based on the tables. If your calculator figured 100% power factor and 100% efficiency that may be why it came up with too small of a conductor even though it supposedly did figure as 125% of FLA.

I have no idea why THHW and XHHW are in both 75 and 90C columns in 310.15(16) They both shoudld be 90C conductors AFAIK.

You said not sure what scenario one would use 90C column -- it is used for ampacity adjustments. You must always have a conductor that meets the termination rating (these days usually 75 C, but with some older equipment it could have 60C terminations, and if using NM cable you always use 60C for termination temp, but can still make adjustments (for number of conductors in raceway or ambient temperature) from 90C ampacity if it has 90C insulation. You basically have to figure out the 75C ampacity, then figure the 90C ampacity and select whichever conductor is larger. If there is no adjustments, the 75C conductor will always be larger. If adjustment factors used are ~70% or higher usually the 75C conductor is still the larger conductor. More then 9 current carrying conductors in raceway will make you increase conductor size most of the time over what you would have if 9 or less conductors. Ambient temp and number of conductors can sometimes add up the adjustment pretty fast.

Great feedback / explanation with the 75C and 90C. I will need to see how to incorporate this in.

Regarding the PF and Efficiency: Correct, when you check the "Use NEC Lookup Tables", the program directly pulls the FLA from the end of Article 430 (these are all table values), and thus locks the PF and Efficiency input fields. To reduce confusion, our program should simply leave the Power Factor and Efficiency input fields empty in this scenario (when "Use NEC Lookup Tables" is checked), and not write in "100", as that is not a proper representation (even though these two fields are locked). What's missing is: the values pulled from Article 430 are not then being multiplied by 1.25. I need to correct this.

Now, if you do NOT check "Use NEC Lookup Tables", you have the option to input in your own PF and Efficiency values, as equations are now be used to calculate the FLA on the backend of the program (where as in the above scenario with the check, the FLA was directly pulled from the tables).

I understand this may be confusing - I'm doing my best to make the user interface as self-explanatory as possible.

 

[GoldDigger]

Two issues that need to be taken into account when doing the temp calculations:

1. Some calculations (absolute ampacity before derating) needs to use the temp columns for the termination temperature rating, not necessarily the maximum wire temp rating.
2. Temp rating to be used as the base for adjustments (CCC fill) and corrections (ambient temp) may depend on the location of the wire, e.g. NM in insulation, bundled, or free in wall cavity. Since this is conduit fill, I guess NM does not come into play. But dry versus wet does affect the column to use for THHN/THW.

 

[kwired]

There is a lot of potential variables, you need to decide what situations you want to be able to include and which you things are rare enough it may not be worth putting them into the tool.

Most of my usage of such a tool would be selecting motor current based on 430 full load tables, multiplying that by 1.25, selecting conductors based on 75C terminations, but 90C insulation for adjustments if necessary. May have other conductors in raceways at times, just depends on the application. Even a long run to a remote location with just a single motor could have control conductors pulled with the motor conductors - those control conductors which are allowed in that situation as long as it is a class 1 control circuit do not count as current carrying conductors in that case for ampacity adjustment reasons, but still need to be counted for raceway fill.

 

[Koosha_engX]

Two issues that need to be taken into account when doing the temp calculations:

1. Some calculations (absolute ampacity before derating) needs to use the temp columns for the termination temperature rating, not necessarily the maximum wire temp rating.
2. Temp rating to be used as the base for adjustments (CCC fill) and corrections (ambient temp) may depend on the location of the wire, e.g. NM in insulation, bundled, or free in wall cavity. Since this is conduit fill, I guess NM does not come into play. But dry versus wet does affect the column to use for THHN/THW.

1) So I'm clear to what you're stating, this ties to what kwired mentioned earlier:

"In real world conductors almost always need to be no smaller then 75C column because terminations are only rated 75C, but you can still use 90C column as a starting point for any ampacity adjustments for number of conductors in raceway or ambient temp adjustments."
​

2) My assumption would be that a user knows what column to select, per the conditions of their real world design. Do you see any holes in my assumption over a user's actions here? Thus, if it's a wet area the user selects X, and if it's a dry area the user selects Y.

 

[Koosha_engX]

There is a lot of potential variables, you need to decide what situations you want to be able to include and which you things are rare enough it may not be worth putting them into the tool.

Most of my usage of such a tool would be selecting motor current based on 430 full load tables, multiplying that by 1.25, selecting conductors based on 75C terminations, but 90C insulation for adjustments if necessary. May have other conductors in raceways at times, just depends on the application. Even a long run to a remote location with just a single motor could have control conductors pulled with the motor conductors - those control conductors which are allowed in that situation as long as it is a class 1 control circuit do not count as current carrying conductors in that case for ampacity adjustment reasons, but still need to be counted for raceway fill.

Exactly. I can't cater to everything as there are endless edge cases; the simplicity factor will then get lost as well. However, the points you have raised thus far, are a must to be fixed, as the outputted accuracy will be compromised.

The edge case you stated with the control wires is definitely a scenario. I'm not sure if I can directly cater to that now. That said, a workaround would be: size the CCC conductors in this tool: http://engcalc.herokuapp.com/#standard-conduit-calculator Thereafter, input in the CCC plus the control wires into this tool: http://engcalc.herokuapp.com/#custom-conduit-fill for calculating the total conduit fill.

On another note, please bare with me here, as I try to digest all of this information you have provided. I'm trying to layout the logic for the code. Is what I have written below correct?

Example #1
We know:

FLA = 70A​

CCC = 8​

Now, a user selects the 90C column for THHN

Per the CCC Adjustment Factor, from the 90C column, the conductor size would be #3 AWG.

For the terminations it's #4 AWG from the 75C column. Thus, we go with the 90C column here (size #3 AWG), as #3 is the larger size.


Example #2
We know:

FLA = 70A​

CCC = 3​

Now, a user selects the 90C column for THHN

From the 90C column, the conductor size would be #6 AWG.

For the terminations it's #4 AWG from the 75C column. Thus, we go with the 75C column here (size #4 AWG), as #4 is the larger size.

 

[GoldDigger]

1) So I'm clear to what you're stating, this ties to what kwired mentioned earlier:

"In real world conductors almost always need to be no smaller then 75C column because terminations are only rated 75C, but you can still use 90C column as a starting point for any ampacity adjustments for number of conductors in raceway or ambient temp adjustments."
​

2) My assumption would be that a user knows what column to select, per the conditions of their real world design. Do you see any holes in my assumption over a user's actions here? Thus, if it's a wet area the user selects X, and if it's a dry area the user selects Y.

I pretty much agree, my point being to refute the assertion that the only input needed was wire type.
But I still think that you may have to support independent selection of column for basic ampacity and for ampacity adjustments and corrections.

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[Koosha_engX]

I pretty much agree, my point being to refute the assertion that the only input needed was wire type.
But I still think that you may have to support independent selection of column for basic ampacity and for ampacity adjustments and corrections.

Sent from my XT1585 using Tapatalk

Point taken. I will add another input field for the termination rating. Thereafter, have an 'if statement' compare the termination rating to the wire rating (where the wire rating may be adjusted / corrected), and then choose the largest size output from the two. That would seemingly handle the issue at hand. And, for the termination rating input, I will default the selection onto the 75C column.

Thanks for the feedback.

 

[Koosha_engX]

Finally the calculator has been updated per all of the wonderful feedback I had received. The 2 calculators again are:

(#1) Conduit Fill Calculator: http://engineercalcs.com/calc/electrical/conduit-fill

• Size conduit and conductors (current carrying and ground) per a motor load or simply using an FLA value, with various conditions considered

(#2) Conduit Sizing Calculator: http://engineercalcs.com/calc/electrical/conduit-sizing

• Simply select your conductors (from the database or custom inputted) and number of conductors, to size a selected conduit type

Since my last posting, below is what has been updated and revised for (#1) per the feedback I had received.

• Ground conductor (EGC) is now sized using Table 430.52. The user has the option to select their desired protective device as well.
• Motor FLA is now properly multiplied by 1.25 in all applicable cases.
• A Termination input field has been added to ensure the sized conductor always meets the termination rating criteria. Thus, the Termination rating is compared to the adjusted conductor rating (if adjustment is necessary), in selecting the final conductor size.
• Voltage drop calculator has been added into the flow for sizing the conductors and conduit.

Please let me know if you have any comments, questions, added feedback, or anything at all. Every message is appreciated.