Tapping a parallel feeder

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ggunn said:
A "what if":

Say I have a feeder that feeds a panel with three parallel sets of conductors and I want to connect a PV system with a single set of conductors on the line side of the panel. What if I used a four port Polaris block to split the PV output three ways and I connect each port to an IPC on a feeder conductor? All the feeder conductors would still look the same as each other.
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I think that would be fine.

To your point about why the code doesn't address this explicitly: my response is that it should. Actually this might be kind of high on the list of revisions that are really needed.
 
ggunn said:
All of which illustrates my point. If it is such a bad idea to tap single conductors in multiconductor sets, why doesn't the code explicitly proscribe it?
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The reason it probably doesn't explicitly prescribe it, is that taps were not anticipated when the rules for parallel sets were initially established. Either taps were not established yet, or taps were simply not common enough to anticipate the possibility of tapping circuits with parallel sets.
 
Carultch said:
The reason it probably doesn't explicitly prescribe it, is that taps were not anticipated when the rules for parallel sets were initially established. Either taps were not established yet, or taps were simply not common enough to anticipate the possibility of tapping circuits with parallel sets.
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Proscribe is what I said, which is the opposite of prescribe, but anyway, the NEC is an evolving document and parallel set conductor tapping has been around for several code cycles. It should be addressed, IMNSHO.

The good news is that in a symposium for the 2020 NEC I attended at Solar Power International, the moderator said that the next NEC is finally going to address what to do with the PV disco in a line side connected system. I wish I'd thought to bring up the parallel set tapping issue.
 
tnoble406 said:
New to the forum, so I ask for your patience in advance. Hope I am in the right place, and that this question falls within the TOS guidelines.
We have a 600 amp MDP with ancient breakers, and are adding a 200 amp panel for some mini-split A/C units. My intent is to install a 200 amp disconnect within 10 feet of the MDP, and use it to supply a w/p panel on the roof where the condensers will be located. The MDP is fed from a 600 amp main disconnect, in parallel. My question is, can this be accomplished by tapping one set of those parallel feeders in the MDP, or do the taps need to be in parallel as well? I hope my explanation is clear enough to be understood, and thank you in advance for your help.
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Think of it this way.

Hold your hand up and make a peace sign with your index and middle finger.
These 2 fingers represent the parallel wires you have feeding the 600 amp MDP.

You can tap these (2) fingers or (Conductors) with a single conductor, or parallel conductors, to feed whatever is new, but, the tap must be made where they join together at the common point at the hand.

Not from the individual index or middle fingers by themselves.

JAP>
 
jap said:
Think of it this way.

Hold your hand up and make a peace sign with your index and middle finger.
These 2 fingers represent the parallel wires you have feeding the 600 amp MDP.

You can tap these (2) fingers or (Conductors) with a single conductor, or parallel conductors, to feed whatever is new, but, the tap must be made where they join together at the common point at the hand.

Not from the individual index or middle fingers by themselves.

JAP>
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The "peace sign" doesn't work; the parallel conductors must be joined at both ends. But nonetheless, I don't think anyone in here needs that sort of simplistic explanation.
 
ggunn said:
The "peace sign" doesn't work; the parallel conductors must be joined at both ends. But nonetheless, I don't think anyone in here needs that sort of simplistic explanation.
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It does work as an explanation.

You don't have to make it so difficult that no one understands.

You don't have to see the whole picture at both ends to explain a tap.

Remember, the OP is only referring to the 600a MDP end, and, as far as no one needing a simplistic explanation, I know YOU may be the all knowing, but, not everyone is.

JAP>
 
If you feel a need to see the whole picture, then simply make a peace sign with both hands, and , Touch both index fingers and middle fingers together to simulate parallel conductors per phase.

Same concept still applies.

JAP>
 
jap said:
It does work as an explanation.

You don't have to make it so difficult that no one understands.

You don't have to see the whole picture at both ends to explain a tap.

Remember, the OP is only referring to the 600a MDP end, and, as far as no one needing a simplistic explanation, I know YOU may be the all knowing, but, not everyone is.

JAP>
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I didn't think anyone in here would need to consult their fingers on how to connect wiring, but maybe you do... :D
 
ggunn said:
I didn't think anyone in here would need to consult their fingers on how to connect wiring, but maybe you do... :D
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You're just pushin buttons now.

Why do you think the OP would have even asked the question if he already knew?

JAP>
 
jap said:
You're just pushin buttons now.

Why do you think the OP would have even asked the question if he already knew?

JAP>
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From reading the question there was no doubt in my mind that he knows what parallel conductors are and what the difference is between tapping one and tapping all of them without looking at his fingers. And c'mon, man, can't you take a joke?
 
ggunn said:
From reading the question there was no doubt in my mind that he knows what parallel conductors are and what the difference is between tapping one and tapping all of them without looking at his fingers. And c'mon, man, can't you take a joke?
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Go back and read post #3.

Then get back with me on clear this is to him.


JAP>
 
ggunn said:
A "what if":

Say I have a feeder that feeds a panel with three parallel sets of conductors and I want to connect a PV system with a single set of conductors on the line side of the panel. What if I used a four port Polaris block to split the PV output three ways and I connect each port to an IPC on a feeder conductor? All the feeder conductors would still look the same as each other.
Click to expand...

Size your Polaris block port quantity as N=2*F+T, where F is the number of sets in the feeder (1 for each inbound wire, 1 for each outbound wire), and T is the number of sets in the tap.
 
The whole point is, nobody was talking to you in post #25, so, there was no need for you to dog the simple peace sign explanation and confuse the issue with " it has to be joined at both ends" as you did in post #26.

JAP>
 
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