Can the supplementary protection in 240.5(A) be upstream of a flexible cord?

Yes, the supplementary protection in 240.5(A) can be upstream of a flexible cord.

Is that what 210.19(4) Exception 2 is saying?

Yes, 210.19(4) Exception 2 allows the use of supplementary overcurrent protection for flexible cords.

Can 240.4(B) be used for sizing flexible cords in relation to 240.5(A)?

No, 240.4(B) cannot be used for sizing flexible cords in relation to 240.5(A).

Explanation

240.5(A) provides requirements for supplementary overcurrent protection of flexible cords and cables. It allows for the use of supplementary overcurrent protection devices, such as fuses or circuit breakers, to protect flexible cords and cables from overcurrents. 210.19(4) Exception 2 allows the use of supplementary overcurrent protection for flexible cords. This exception allows the overcurrent protection device to be located either upstream or downstream of the flexible cord.* 240.4(B) provides requirements for the ampacity of flexible cords and cables. It states that the ampacity of flexible cords and cables shall not exceed the values specified in Table 400.5(A) or 400.5(B). 240.4(B) opens with "other than flexible cords", which means it does not apply to flexible cords. Therefore, 240.4(B) cannot be used for sizing flexible cords in relation to 240.5(A).

Conclusion:

The supplementary protection in 240.5(A) can be upstream of a flexible cord. This is allowed by 210.19(4) Exception 2. 240.4(B) cannot be used for sizing flexible cords in relation to 240.5(A). Flag for review