using the NEC

[EVAN DAVIS]

while studying motor branch circuits, it became a problem for me to use the proper charts on 310.16, 310.17. no matter what, it didn't work out, what is the proper way to use those charts?

 

[augie47]

welcome to the forum

not near enough information. 310.16 is the most applicable ampacity chart. can you give an example of the problem you are having ?

 

[dcspector]

Step 1 FLC 430.248 OR 430.250
Step 2 430.32
Step 3 430.22 FLC x 125% then to 310.16
Step 4 430.52
Step 5 430.24
Step 6 430.62

 

[EVAN DAVIS]

thanks augie47, more exactly, I'm unsure of using the chart given the temperature rating since there seems to be more than onw to choose from given the insulation type

 

[EVAN DAVIS]

thanks dcspector, I will only use 310.16?

 

[jumper]

thanks augie47, more exactly, I'm unsure of using the chart given the temperature rating since there seems to be more than onw to choose from given the insulation type

If you are talking about why some conductor insulations, like THHW and XHHW, are in two different columns in T310.16, then look at T310.13. It depends on whether it is a wet or dry location. I asked Augie47 the same question and he explained it to me. See 110.14(C) also.