Optional Calc Method

[Bernard1599]

When using the optional method to calculate a service for a dwelling, how do you size the neutral? Do you size it by using the standard method? That seems like twice the work if you have to go back and recalculate all of the loads with their respective demands.

Please point me in the right direction. Genuinely appreciate any assistance.

Regards,

 

[Dennis Alwon]

When using the optional method to calculate a service for a dwelling, how do you size the neutral? Do you size it by using the standard method? That seems like twice the work if you have to go back and recalculate all of the loads with their respective demands.

Please point me in the right direction. Genuinely appreciate any assistance.

Regards,

I am not sure how you would do it. I would think you could do an opt. cal using just the 120 volt loads but I would not bet on that. Generally I just downsize the neutral one size I am sure I can downsize it more but the trouble to calculate it isn't worth it to me ( Obviously--since I am not even sure how to calc it).

 

[Bernard1599]

Hi Dennis,

Thank you for your response.

I agree. In the real world it seems like too much effort to work out. However, I was working on some test calculations using the standard method and then they went into asking us to use the optional method for the next few problems. After I finished working out the phase loads, I could not find anything in the Code that even remotely helped me understand how to size the neutral using the op method. It is probably in there somewhere but I cannot find it.

Thanks again.

 

[Bernard1599]

Generally I just downsize the neutral one size I am sure I can downsize it more but the trouble to calculate it isn't worth it to me ( Obviously--since I am not even sure how to calc it).

Hi Dennis,

Thank you for your response.

I agree. In the real world it seems like too much effort to work out. However, I was working on some test calculations using the standard method and then they went into asking us to use the optional method for the next few problems. After I finished working out the phase loads, I could not find anything in the Code that even remotely helped me understand how to size the neutral using the op method. It is probably in there somewhere but I cannot find it.

Thanks again.

 

[Paul B]

When using the optional method to calculate a service for a dwelling, how do you size the neutral? Do you size it by using the standard method? That seems like twice the work if you have to go back and recalculate all of the loads with their respective demands.

Please point me in the right direction. Genuinely appreciate any assistance.

Regards,

I used the optional method back in the seventies taking the test and was failed because the grader could not figure out my work. I did get the chance to show him what I had done and he passed me.