Overcurrent (Overload) Protection for Service Condutors and Equipment

[david luchini]

BTW, I'm not buying the argument that 215.3 figures into this issue at all. 215.3 is for feeder overcurrent protection, not service conductor overcurrent protection. The mathematics may eventually relate 215.3 to 230.90 but there is no specific link either implied or stated in the Code that I am aware of between the two.

Unfortunately, I am not somewhere where I could draw a picture an post it, but here is a simple exercise with less than 10 steps that illustrates my point...

1) Grab a piece of paper and draw a square in the center. Label the square "Service OCPD."

2) Draw a line segment leaving the left side of the square. Label this "Service Conductors."

3) Draw a line segment leaving the right side of the square. Label this "Main Feeder."

4) Indicate a load of 100A non-continuous plus 100A continuous for the Main Feeder, look under 215.2 and find that the main feeder size must have an ampacity of 225A. #4/0 meets this size requirement, so label the main feeder as #4/0 conductors.

5) Look under 215.3 and finder that the OCPD protecting the feeder must have a min size of at least 225A. Write 225A in the square as the size of the OCPD protecting the feeder conductors.

6) Sit back and celebrate your "A-ha" moment.

Much shorter than 10 steps.

 

[Clark Mason @MTC]

There is nothing in Article 230, as you pointed out in your original question, that establishes a minimum OCPD size for the service entrance conductors. You have to look elsewhere in the Code for that.

Again, I think this was, perhaps not adequately stated, the heart of my question. Why doesn't 230 give us a minimum size for the device.? 210 does, 215 does, why not 230?

 

[Clark Mason @MTC]

Unfortunately, I am not somewhere where I could draw a picture an post it, but here is a simple exercise with less than 10 steps that illustrates my point...

1) Grab a piece of paper and draw a square in the center. Label the square "Service OCPD."

2) Draw a line segment leaving the left side of the square. Label this "Service Conductors."

3) Draw a line segment leaving the right side of the square. Label this "Main Feeder."

4) Indicate a load of 100A non-continuous plus 100A continuous for the Main Feeder, look under 215.2 and find that the main feeder size must have an ampacity of 225A. #4/0 meets this size requirement, so label the main feeder as #4/0 conductors.

5) Look under 215.3 and finder that the OCPD protecting the feeder must have a min size of at least 225A. Write 225A in the square as the size of the OCPD protecting the feeder conductors.

6) Sit back and celebrate your "A-ha" moment.

Much shorter than 10 steps.

I think we're going to have to agree to disagree on this one. FEEDERS are different than SERVICES. The code, as far as I am aware, does not allow us to use rules in 215 for conductors that are governed by 230 - unless and until you can show me that connection, explicitly stated in NFPA 70, we're never gonna agree.

However, my contention is that this matter could be easily resolved with (following your logic):

230.90(A)(1) The minimum rating or setting of the overcurrent device shall be calculated in accordance with 215.3

 

[david luchini]

Again, I think this was, perhaps not adequately stated, the heart of my question. Why doesn't 230 give us a minimum size for the device.? 210 does, 215 does, why not 230?

I'm not sure how many ways I can same the same thing...There isn't anything in Art. 230 about a minimum size for the OCPD because it has already been covered by Art. 215.

I think we're going to have to agree to disagree on this one. FEEDERS are different than SERVICES. The code, as far as I am aware, does not allow us to use rules in 215 for conductors that are governed by 230 - unless and until you can show me that connection, explicitly stated in NFPA 70, we're never gonna agree.

However, my contention is that this matter could be easily resolved with (following your logic):

230.90(A)(1) The minimum rating or setting of the overcurrent device shall be calculated in accordance with 215.3

Did you take my simple exercise from post #61? Sorry, not trying to be silly, but I've given you the answer to your question and tried to explain it, but it obviously hasn't sunken in. A picture will be worth a thousand words in this case.

 

[Clark Mason @MTC]

I'm not sure how many ways I can same the same thing...There isn't anything in Art. 230 about a minimum size for the OCPD because it has already been covered by Art. 215.

And I'm not sure how many ways I can say it either; 230 DOES NOT give a citation to 215 (or anything else for that matter, which is the heart of my original concern) as a method for sizing the device. I gave an example of what I thought would make a good reference, using your logic (as fallible as it seems to me).

I think it best we part company on this issue. I am convinced you are wrong and you have done nothing, as Mr. Holt so powerfully reminds us all the time, using the actual code to prove any different. Your EE arrogance is showing a bit.

Thank you for your time and consideration.

 

[david luchini]

And I'm not sure how many ways I can say it either; 230 DOES NOT give a citation to 215 (or anything else for that matter, which is the heart of my original concern) as a method for sizing the device. I gave an example of what I thought would make a good reference, using your logic (as fallible as it seems to me).

230 DOESN'T NEED to give a citation to 215. That is completely irrelevant for the answer to your question.

Also, I don't see any example that you have given using my logic as a reference.

I think it best we part company on this issue. I am convinced you are wrong and you have done nothing, as Mr. Holt so powerfully reminds us all the time, using the actual code to prove any different. Your EE arrogance is showing a bit.

Thank you for your time and consideration.

I beg your pardon? My EE arrogance? I've given you a direct answer to your simple question, and did my best to explain the reasoning. And instead of taking to time to understand the answer to your question, you've prattled on. It is showing your arrogance to decide that the answer that you do not like is the obvious and correct answer.

 

[david luchini]

Like I said, a picture is worth a thousand words.

 

[Clark Mason @MTC]

Okay, I tried my best to disengage but if you insist....

 

[david luchini]

Okay, I tried my best to disengage but if you insist....

Disengage, if you wish.

Don't dismiss that effort that I have given to try to answer your question. That's just rude.

 

[Clark Mason @MTC]

230 DOESN'T NEED to give a citation to 215. That is completely irrelevant for the answer to your question.

Also, I don't see any example that you have given using my logic as a reference.

Here was my idea since you seemed to have overlooked it.


230.90(A)(1) The minimum rating or setting of the overcurrent device shall be calculated in accordance with 215.3

 

[Clark Mason @MTC]

Disengage, if you wish.

Don't dismiss that effort that I have given to try to answer your question. That's just rude.

I'm trying to not make you look bad - I think that's pretty nice of me but if you want....

 

[david luchini]

Here was my idea since you seemed to have overlooked it.


230.90(A)(1) The minimum rating or setting of the overcurrent device shall be calculated in accordance with 215.3

Why bother? The code already adequately cover the minimum size of the OCPD. You would just be adding words for the sake of adding words.

 

[david luchini]

I'm trying to not make you look bad - I think that's pretty nice of me but if you want....

Take your best shot. You are already making yourself look pretty foolish.

 

[Clark Mason @MTC]

Why bother? The code already adequately cover the minimum size of the OCPD. You would just be adding words for the sake of adding words.

But isn't the argument all about the fact that the code doesn't cover that sizing? If it does, exactly where?

 

[david luchini]

But isn't the argument all about the fact that the code doesn't cover that sizing? If it does, exactly where?

Again...215.3.

Did you look at Post #67?

Is it really that difficult to understand that the OCPD at the load end of the service conductors is the same OCPD at the supply end of the feeder conductors?

 

[Clark Mason @MTC]

Again...215.3.

Did you look at Post #67?

Is it really that difficult to understand that the OCPD at the load end of the service conductors is the same OCPD at the supply end of the feeder conductors?

I understand in that extremely narrow example, the OCPD for the service entrance conductors is, in fact, the OCPD for the feeder conductors.

But again, I contend that 215.3 does not apply in a more general case. 230.90 is the governing rule here. I am aware of no Code regulation that explicitly states that service conductors shall be protected by an overcurrent device whose size is calculated in accordance with any other article.

Does the Code explicitly state that the overcurrent device required in 230.90 be calculated in accordance with 215.3?

If it doesn't explicitly state it, it is NOT a rule and therefore not applicable nor enforceable .

 

[david luchini]

I understand in that extremely narrow example, the OCPD for the service entrance conductors is, in fact, the OCPD for the feeder conductors.

That is not for an extremely narrow example. That is for ALL installations. Could you illustrate just one example where the load side of the service OCPD is not protecting a feeder? And yes, I will happily point out that for a service supplying a single circuit, that the service OCPD would protecting a branch circuit. In that case 210.19 and 210.20 would apply instead of 215.2 and 215.3.

But again, I contend that 215.3 does not apply in a more general case. 230.90 is the governing rule here. I am aware of no Code regulation that explicitly states that service conductors shall be protected by an overcurrent device whose size is calculated in accordance with any other article.

230.90 has nothing with the minimum size of the OCPD. 230.90 relates to protecting conductors at their ampacity. It is irrelevant to the question you asked.

Does the Code explicitly state that the overcurrent device required in 230.90 be calculated in accordance with 215.3?

No. There is exactly ZERO reasons for the Code to explicitly state that...so it does not.

If it doesn't explicitly state it, it is NOT a rule and therefore not applicable nor enforceable .

The rule in 215.3 is applicable to all installations governed by the NEC, and is enforceable to all installations, therein.

You cannot ignore that rule no matter how much you would like.

I guess a thousand words isn't enough, because it is clear that you still do not understand the answer. I wish I could find a picture worth a million words.

 

[Clark Mason @MTC]

Well, guys and gals, I'm at my wits end. This is going round and round with no end in sight.

A few of the earlier posters in this thread questioned how a rule in 215 can apply to conductors required in 230. Mr. Luchini, I agree with those posts and would like to suggest a re-reading of them.

I've tried to plainly, and as clearly as I can possibly state, claim that Article 215 does not apply to Article 230. While I do agree that 215.3 applies to all feeders in all installations, it does not apply to any service conductors in any installation, your comment "The rule in 215.3 is applicable to all installations governed by the NEC, and is enforceable to all installations, therein." notwithstanding,

I believe Mr. Luchini's assertion at this point is that every single instance of every single service supplying every single installation is reducible to a service supplying a feeder. If that is indeed the case, I will concur that there is no use for any clarification or elucidation concerning overcurrent protection for service entrance conductors. However, does that not logically mean that at least a few rules in Part VII of Article 230 are redundant since those rules are covered in Article 215?

 

[david luchini]

Well, guys and gals, I'm at my wits end. This is going round and round with no end in sight.

A few of the earlier posters in this thread questioned how a rule in 215 can apply to conductors required in 230. Mr. Luchini, I agree with those posts and would like to suggest a re-reading of them.

I have read them all. The problem is that you (and those posts) are offering a red herring. The rule in 215 has nothing to do with the conductors required in 230.

I believe Mr. Luchini's assertion at this point is that every single instance of every single service supplying every single installation is reducible to a service supplying a feeder. If that is indeed the case, I will concur that there is no use for any clarification or elucidation concerning overcurrent protection for service entrance conductors. However, does that not logically mean that Part VII of Article 230 is redundant since all of those rules are covered in Article 215?

The rule in 215.3 applies to all OCPDs protecting feeders. And yes, all service OCPDs will be protecting feeders (unless, as I mentioned, you have a rare installation of a single branch circuit.)

And no, that does not logically mean that Part VII of Article 230 is redundant "since all of those rules are covered in Article 215." None of the requirements in Part VII of Article 230 is covered in Article 215.

You could argue that Part VII of Article 230 is redundant to Article 240, but there is enough unique to service conductors in Part VII of Article 230. In fact 240.3 and 240.21(D) specifically direct you to Article 230 for service conductors.

 

[Clark Mason @MTC]

The rule in 215.3 applies to all OCPDs protecting feeders. And yes, all service OCPDs will be protecting feeders (unless, as I mentioned, you have a rare installation of a single branch circuit.)

And no, that does not logically mean that Part VII of Article 230 is redundant "since all of those rules are covered in Article 215." None of the requirements in Part VII of Article 230 is covered in Article 215.

You could argue that Part VII of Article 230 is redundant to Article 240, but there is enough unique to service conductors in Part VII of Article 230. In fact 240.3 and 240.21(D) specifically direct you to Article 230 for service conductors.

This, I agree with, I misspoke before re-reading clearly. I would disagree that NONE of the arguments is covered because there is some overlap with the GFCI protection for each. Please excuse the mistake on my part.