Tap rule question

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wwhitney said:
Well, I'm just applying Charlie's rule without any preconceptions.

Cheers, Wayne
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That's fine... but there are some instances where that gets you in trouble... and this is one of them. Some industry-accepted principles are not written as codified text simply because they are, well, industry accepted... :slaphead:

If circuit conductors are permitted to be both feeder and branch circuit conductors, why bother with the separate definitions and articles to begin with.... just sum 'em all up in an article titled "Circuits".
 
would A,B or C be exceptionable as a feeder

A. >>>>> 10 ft conductors >>>>>(60 amp device outlet)
(60 amp breaker)>>>>>feeder>>>>> (20 amp breaker)>>>>>branch circuit>>>>> 20 amp outlet
>>>>> 10 ft conductors >>>>>(60 amp device outlet)


B >>>>> 10 ft conductors >>>>>(50 amp device outlet)
(60 amp breaker)>>>>>feeder>>>>> (20 amp breaker)>>>>>branch circuit>>>>> 20 amp outlet
>>>>> 10 ft conductors >>>>>(50 amp device outlet)



C >>>>> 10 ft conductors >>>>>(60 amp device outlet)
(60 amp breaker)>>>>>feeder>>>>> (20 amp breaker)>>>>>branch circuit>>>>> 20 amp outlet
>>>>> 10 ft conductors >>>>>(50 amp device outlet)
 
Smart $ said:
If circuit conductors are permitted to be both feeder and branch circuit conductors, why bother with the separate definitions and articles to begin with.... just sum 'em all up in an article titled "Circuits".
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As I said to Don, if a conductor is a feeder and a branch circuit conductor, then it has to comply with rules for both. Since they are different roles, they have different rules. If someone could actually point out a conflict between the rules for the two uses, I'd be more than happy to concede that the NEC prohibits that situation. But absent any such conflict, it is NEC compliant.

Obviously in configurations where a conductor is both a feeder and a branch circuit conductor, that dual role could be avoided by adding more OCPD (to make it into a feeder only) or by running more conductors (to separate out the two roles). But if that serves no electrical or safety function, why waste the material?

Cheers, Wayne
 
Wow I had no idea this post would generate so much discussion. One of the responses on page 1 asked what size conductors I would use between the tap point and the 20A fuses -- my initial thought was that these would be #12, but it seems like some posters believe these conductors should be rated for 60A.

Maybe I should ask my question a different way: If you believe the circuit description in my original post to be a violation, how would you change things such that the installation is code compliant?

Thanks again for the feedback.
 
AZElectrical said:
Wow I had no idea this post would generate so much discussion. One of the responses on page 1 asked what size conductors I would use between the tap point and the 20A fuses -- my initial thought was that these would be #12, but it seems like some posters believe these conductors should be rated for 60A.

Maybe I should ask my question a different way: If you believe the circuit description in my original post to be a violation, how would you change things such that the installation is code compliant?

Thanks again for the feedback.
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Assuming that the circuit is large enough for the total load of both 60 amp rec. and the 20 amp branch circuit. Everyone here would agree if you provide overcurrent protection for both 60 amp rec, than you would have a feeder and three branch circuits.

I do not think anyone indicated that the 20 amp circuit could not tap the 60 amp circuit if the 60 amp rec. portion became branch circuits.
 
AZElectrical said:
Wow I had no idea this post would generate so much discussion. One of the responses on page 1 asked what size conductors I would use between the tap point and the 20A fuses -- my initial thought was that these would be #12, but it seems like some posters believe these conductors should be rated for 60A.

Maybe I should ask my question a different way: If you believe the circuit description in my original post to be a violation, how would you change things such that the installation is code compliant?

Thanks again for the feedback.
Click to expand...

Right that was my question. There seems to be two potential point of debate here. First imagine the situation in the OP where the conductors between the tap point and the 20 A OCPD are 60 amp rated. The debate here seem to be just over some of the conductors being both a feeder and branch circuit. Now let the conductors between the tap point and the 20 A OCPD be 20 amp rated. I dont see any allowed branch circuit tap rule for this. But was I reading correctly that Wayne was proposing that the act of tapping it, turns it into a feeder and now we can use the feeder tap rules? If so, to me it is more like feeding a device with a feeder which appears to be allowed by 240.21(B)(1)(1)(b).
 
electrofelon said:
But was I reading correctly that Wayne was proposing that the act of tapping it, turns it into a feeder and now we can use the feeder tap rules?
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If you add conductors to an OCPD to a load, those new conductors are certainly a feeder, because of the downstream OCPD. So regardless of what you call the original conductors, you can apply the feeder tap rules to them. The 'feeder' in 'feeder tap' refers to what you are making, not where you get the power.

Cheers, Wayne
 
I just remembered they got rid of the mysterious "feeder supplying a device" phrase in 240.21(B)(1)(1)(b) so scratch that idea. I was originally thinking there was another way to think about this as having two feeder taps.
 
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