Overcurrent (Overload) Protection for Service Condutors and Equipment

[david luchini]

I think it's sloppy to say it that way. Rather I would say the same OCPD is meeting both the 230 and 215 requirements.

The is no OCPD sizing requirement in 230. The was the point of the original post.

 

[david luchini]

I still disagree 215.3 is for overcurrent protection of a feeder.

Overcurrent protection of a service conductor is covered in 230.90.

I don't think you have understood what the OP was asking.

 

[electrofelon]

The is no OCPD sizing requirement in 230. The was the point of the original post.

Ummm, part VII? I must not be understanding what you are getting at.

 

[david luchini]

Ummm, part VII? I must not be understanding what you are getting at.

Reread the original post.

 

[packersparky]

NA

 

[electrofelon]

Reread the original post.

Did several times before I replied before.

 

[david luchini]

Did several times before I replied before.

Then you must have read this...

The code specifies similar requirements for overcurrent protection for conductors and equipment in:
210.20
215.3
But I can't find any such requirement for service equipment in Article 230 Part VII (or part VI for that matter even that is only for disconnect rating).

The response to which is this...

There is nothing in Article 230 regarding the overcurrent protection sizing because 215.3 already covers it.

 

[kwired]

I don't think you have understood what the OP was asking.

Maybe, possible you took it wrong also.

I see asking why specific conductor sizing requirements is mentioned in 210, 215 and 230 with pretty much same wording and then pointing out overcurrent protection requirements are nearly the same in 210 and 215 but similar wording seems to be absent in 230 and question basically is why is it that way.

There is overcurrent protection requirements in 230, it just isn't as similarly worded as it is in 210 and 215, and has conditions that can change it up a little.

 

[Dennis Alwon]

I think what David is saying is that the overcurrent protective device in the main disconnect protects the wiring of the service conductors since the overcurrent protective device is equal to or smaller than the service conductor ampacity.

It will not protect the wiring ahead of the breaker but it will give load protection via the main breaker. Since that is there is no reason to have it again in article 230. I think that is what David is saying.

Of course, that changes when the 6 disconnect rules is used.

 

[kwired]

I think what David is saying is that the overcurrent protective device in the main disconnect protects the wiring of the service conductors since the overcurrent protective device is equal to or smaller than the service conductor ampacity.

It will not protect the wiring ahead of the breaker but it will give load protection via the main breaker. Since that is there is no reason to have it again in article 230. I think that is what David is saying.

Of course, that changes when the 6 disconnect rules is used.

There is a lot of repeating of information in the NEC. Go to the raceway articles and the .1 through .100 are often cut/pasted with only minor changes here and there. But it helps to clarify things when you are looking at 344 and realize this applies to RMC, but you are dealing with EMT and you should maybe check 358 to make sure something isn't different there, even though much of the content is similar in each article. Many things are similar in 210, 215 and 230 as well but there are differences.

 

[david luchini]

I see asking why specific conductor sizing requirements is mentioned in 210, 215 and 230 with pretty much same wording and then pointing out overcurrent protection requirements are nearly the same in 210 and 215 but similar wording seems to be absent in 230 and question basically is why is it that way.

Yes, that is what was being asked. This is the answer to the question...

There is nothing in Article 230 regarding the overcurrent protection sizing because 215.3 already covers it.

 

[kwired]

Yes, that is what was being asked. This is the answer to the question...

And you have been asked to explain how that covers it. 215 is presumably for feeders not services.

I will agree to the comment that one device can satisfy both service and feeder requirements and does happen quite often.

I gave an example of a service with overcurrent protection suitable for the service conductors, but with feeder taps only on the load side of the service disconnect. Such feeder taps still need an additional overcurrent device at the load end of the tap before 215.3 is satisfied.

 

[david luchini]

And you have been asked to explain how that covers it. 215 is presumably for feeders not services.

I gave an example of how it covers it in post #15.

I will agree to the comment that one device can satisfy both service and feeder requirements and does happen quite often.

I gave an example of a service with overcurrent protection suitable for the service conductors, but with feeder taps only on the load side of the service disconnect. Such feeder taps still need an additional overcurrent device at the load end of the tap before 215.3 is satisfied.

With your example of feeder taps on the load side of the disconnect, it is still Art. 215 which is providing the direction for sizing the main OCPD.

 

[kwired]

I gave an example of how it covers it in post #15.




With your example of feeder taps on the load side of the disconnect, it is still Art. 215 which is providing the direction for sizing the main OCPD.

Only thing I am seeing in post 15 is the protection of a feeder inherently protects the service conductor - one device fulfills two needs.

There is no indication in 215.3 or anything in 230 that points back to 215.3 that this is also considered to be service conductor overcurrent protection, it just happens to work out that way most of the time.

And I do agree that taps on load side are feeders and covered by 215, but their overcurrent protection isn't coming from 215.3, it is a special permission in 240.21. Now technically there is still a feeder before you can tap it, though it may be composed of nothing more than a multiport lug on the switch or breaker and not an art 310 conductor.

 

[david luchini]

Only thing I am seeing in post 15 is the protection of a feeder inherently protects the service conductor - one device fulfills two needs.

What you should see in post 15 is the sizing of the main OCPD based on Art. 215.

There is no indication in 215.3 or anything in 230 that points back to 215.3 that this is also considered to be service conductor overcurrent protection, it just happens to work out that way most of the time.

That isn't the OP's question.

And I do agree that taps on load side are feeders and covered by 215, but their overcurrent protection isn't coming from 215.3, it is a special permission in 240.21.

The sizing of the overcurrent protection for the feeder taps comes from 215.3, not from 240.21. But that is irrelevant to the point I am making.

Now technically there is still a feeder before you can tap it, though it may be composed of nothing more than a multiport lug on the switch or breaker and not an art 310 conductor.

The overcurrent protection for the feeder that is being tapped is sized 215.3.

 

[kwired]

Replies withing quote:

What you should see in post 15 is the sizing of the main OCPD based on Art. 215. Said OCPD coverd by 215.3 is for the feeder on the load side of the OCPD and has nothing to do with what is on the supply side of that OCPD.



That isn't the OP's question. I don't see it that way, unless OP states otherwise, I'm sticking with what I have gotten out of it so far.



The sizing of the overcurrent protection for the feeder taps comes from 215.3, not from 240.21. But that is irrelevant to the point I am making.I don't see anything about tap conductors in 215.3. Like I said the feeder may be nothing more than a multiport lug on a switch or breaker.



The overcurrent protection for the feeder that is being tapped is sized 215.3. that I do agree with, once you tap that feeder then you are looking at 240.21 for overcurrent protection limitations on the tap conductor

 

[david luchini]

Said OCPD coverd by 215.3 is for the feeder on the load side of the OCPD and has nothing to do with what is on the supply side of that OCPD.

What's on the supply side of the OCPD is not relevant to the question asked. The question is about the sizing of the OCPD.

I don't see it that way, unless OP states otherwise, I'm sticking with what I have gotten out of it so far.

See your post #28.

I don't see anything about tap conductors in 215.3. Like I said the feeder may be nothing more than a multiport lug on a switch or breaker.

The tap conductors are feeders. 215.2 and 215.3 apply to feeders.

that I do agree with, once you tap that feeder then you are looking at 240.21 for overcurrent protection limitations on the tap conductor

215.2 and 215.3 provide the minimum required size of the feeder conductors and the feeder overcurrent protection. 240.21 is "Location in Circuit." 240.21 allows you to provide overcurrent protection to the tap conductors at other than the point they receive their supply, with additional provisions that must be met.

 

[david luchini]

Let me try it this way...

The question is...why doesn't Art. 230 have OCPD sizing requirements the same way Art. 210 and Art. 215 do? After all, all 3 articles have the same requirements for conductor sizing.

I'm designing a building.

I calculate all my branch circuit loads on each subpanel. I size my branch circuit conductors and OCPD's per 210.19 and 210.20.

I add all my branch circuit loads for each panel, apply Art 220 demand factors, and size my feeder circuits conductors and OCPD's per 215.2 and 215.3 for each panel.

I add all the branch circuit loads for the entire building at the main panel (or main breaker), apply Art 220 demand factors, and size my main OCPD per 215.3.

I then go to Art 230 and size my service entrance conductors.....


What should be included in Art 230 for sizing the main OCPD (similar to Arts. 210 and 215) for the main OCPD that I just sized in step 3 above?

 

[kwired]

What's on the supply side of the OCPD is not relevant to the question asked. The question is about the sizing of the OCPD.

And mentioning the 210 and 215 and asking about 230 stuff seems to indicate to me he is asking why isn't it the same for service conductors though feeders and branch circuits are almost identically worded, and on top of that mentins the fact that minimum conductor size is almost identical for all three.

The tap conductors are feeders. 215.2 and 215.3 apply to feeders.

Yes they are, but overcurrent protection of the tap involves 240.21 Same tap size and protection could be applied to different sized feeders in some instances, can depend on if 10 or 25 foot tap rule is being used or even if inside/outside.

215.2 and 215.3 provide the minimum required size of the feeder conductors and the feeder overcurrent protection. 240.21 is "Location in Circuit." 240.21 allows you to provide overcurrent protection to the tap conductors at other than the point they receive their supply, with additional provisions that must be met.

Correct, and tap rules vary according to conditions. Nothing in 215.3 applies to protection of a tap conductor, it applies to the feeder the tap conductor is connected to, the overcurrent protection of the tap is dependent on conditions spelled out in 240.21.

 

[david luchini]

And mentioning the 210 and 215 and asking about 230 stuff seems to indicate to me he is asking why isn't it the same for service conductors though feeders and branch circuits are almost identically worded, and on top of that mentins the fact that minimum conductor size is almost identical for all three.

Exactly...And the answer is Art. 215 already covers it. See my post #38 above.

Yes they are, but overcurrent protection of the tap involves 240.21 Same tap size and protection could be applied to different sized feeders in some instances, can depend on if 10 or 25 foot tap rule is being used or even if inside/outside.

Nothing in 240.21 relates the to minimum required overcurrent protection size for the tap. If I had a 90A continuous load that I wanted to tap from a 400A feeder, 240.21 would permit me to run #3 tap conductors to a 100A c/b. Art. 215 does not.

Correct, and tap rules vary according to conditions. Nothing in 215.3 applies to protection of a tap conductor, it applies to the feeder the tap conductor is connected to, the overcurrent protection of the tap is dependent on conditions spelled out in 240.21.

215.3 tells you the minimum allowable size for the protection of the tap conductor. It is a feeder conductor.