PI: 240.4 (Third)

[wwhitney]

Add "Services" to the table in 240.4(G). In this post I just list the new table row, rather than the whole table.

Cheers, Wayne

(G) Overcurrent Protection for Specific Conductor Applications.
Overcurrent protection for the specific conductors shall be permitted to be provided as referenced in Table 240.4(G).

Services 230 230.90(A)

Statement of Problem and Substantiation for Public Input

Article 230.90(A) Exception 3 permits multiple overcurrent devices to protect service conductors. Further "the sum of the ratings of the circuit breakers or fuses shall be permitted to exceed the ampacity of the service conductors, provided the calculated load does not exceed the ampacity of the service conductors."

So this is an allowable case in which conductors are not "protected against overcurrent in accordance with their ampacities." As such, it needs to be listed in 240.4 as one of the exceptions. Since this is a specific conductor application, listing it under 240.4(G) is appropriate.

 

[don_resqcapt19]

Add "Services" to the table in 240.4(G). In this post I just list the new table row, rather than the whole table.

Cheers, Wayne

(G) Overcurrent Protection for Specific Conductor Applications.
Overcurrent protection for the specific conductors shall be permitted to be provided as referenced in Table 240.4(G).

Services 230 230.90(A)

Statement of Problem and Substantiation for Public Input

Article 230.90(A) Exception 3 permits multiple overcurrent devices to protect service conductors. Further "the sum of the ratings of the circuit breakers or fuses shall be permitted to exceed the ampacity of the service conductors, provided the calculated load does not exceed the ampacity of the service conductors."

So this is an allowable case in which conductors are not "protected against overcurrent in accordance with their ampacities." As such, it needs to be listed in 240.4 as one of the exceptions. Since this is a specific conductor application, listing it under 240.4(G) is appropriate.

Already covered by the reference to Article 230 in Table 240.3.

 

[wwhitney]

Already covered by the reference to Article 230 in Table 240.3.

I don't believe so. That section says:

"240.3 Other Articles. Equipment shall be protected against overcurrent in accordance with the article in this Code that covers the type of equipment specified in Table 240.3."

So it's imposing a requirement on a broader category of items (equipment, not just conductors) for the specific cases listed in Table 240.3. While 240.4 imposes a requirement on a smaller category of items (just conductors) in all cases except those listed in 240.4(A) through 240.4(H). These are just two potentially overlapping requirements, and you have to comply with both.

For example, Table 240.3 includes "Branch Circuits Article 210," presumably because of the requirements in Part II, such as the rules prohibiting a 20A receptacle (equipment) on a 30A circuit. Nonetheless, 240.4(E) Tap Conductors refers to 210.19(C) and (D) to indicate those are allowable cases where conductors need not be protected in accordance with their ampacity. The presence of Article 210 in Table 240.3 does not negate the need to reference 210.19(C) and (D) in 240.4(E).

Similarly, the presence of Article 230 in Table 240.3 does not negate the need to reference 230.90(A) in 240.4(G).

Cheers, Wane

 

[don_resqcapt19]

I don't believe so. That section says:

"240.3 Other Articles. Equipment shall be protected against overcurrent in accordance with the article in this Code that covers the type of equipment specified in Table 240.3."

So it's imposing a requirement on a broader category of items (equipment, not just conductors) for the specific cases listed in Table 240.3. While 240.4 imposes a requirement on a smaller category of items (just conductors) in all cases except those listed in 240.4(A) through 240.4(H). These are just two potentially overlapping requirements, and you have to comply with both.

For example, Table 240.3 includes "Branch Circuits Article 210," presumably because of the requirements in Part II, such as the rules prohibiting a 20A receptacle (equipment) on a 30A circuit. Nonetheless, 240.4(E) Tap Conductors refers to 210.19(C) and (D) to indicate those are allowable cases where conductors need not be protected in accordance with their ampacity. The presence of Article 210 in Table 240.3 does not negate the need to reference 210.19(C) and (D) in 240.4(E).

Similarly, the presence of Article 230 in Table 240.3 does not negate the need to reference 230.90(A) in 240.4(G).

Cheers, Wane

That is not how the table works...you follow the rules in 230 for service conductors and do not even look at 240.

 

[wwhitney]

That is not how the table works...you follow the rules in 230 for service conductors and do not even look at 240.

240.3 just doesn't say that. There's no language there that says to ignore the rest of Article 240. Charlie's Rule.

Cheers, Wayne

 

[don_resqcapt19]

240.3 just doesn't say that. There's no language there that says to ignore the rest of Article 240. Charlie's Rule.

Cheers, Wayne

That is exactly what the table says...It very clearly says for services, you don't even look at 240.
240.3 Other Articles.
Equipment shall be protected against overcurrent in accordance with the article in this Code that covers the type of equipment specified in Table 240.3.

 

[wwhitney]

That is exactly what the table says...It very clearly says for services, you don't even look at 240.

It literally does not say anything like that. There is no language saying that the requirements in the articles mentioned in the table are exclusive of other requirements, or that the rest of article 240 does not apply. By default, all of 240 applies, and there are zero instructions to the contrary.

Cheers, Wayne

 

[wwhitney]

I mean, look at just a few of the ridiculous consequences we get from the idea that article 240 does not apply to services:

- 240.4(D) doesn't apply, so we can have a 20A service on #14 Cu in a 75C wiring method
- 240.8 doesn't apply, so if I want a 300A service disconnect, I can get an MLO panelboard and field assemble (3) 100A breakers in parallel as the service disconnect.
- 240.22 doesn't apply, so we can put a fuse in the grounded conductor.
- 240.24(B) on occupant access to OCPDs doesn't apply to service OCPD.
- 240.81 doesn't apply, so the service circuit breaker can be down for "on".

Cheers, Wayne