I was looking thru the code book as it relates to feeder taps. Pretty obvious [or at least I thought] the definition of a feeder tap would be a tap of a feeder downstream from an overcurrent protective device. [transformer secondary conductors also considered a tap], now if there is a disconnect switch [non fused] with double load lugs would it be acceptable to install small conductors [for example incoming line conductors are 1/0, and load secondaries are #4] each secondary would not exceed the distance requirement of the tap rule and call this a "tap", however with these connected to the load side of a disconnect is it still considered a "tap" or would you have to provide full 1/0 to a dist. block and then tap. We were having this debate on weather or not a a reduced conductor connected to the load side of a fused or non fused disc. or even a breaker would be considered a tap or is this always a feeder?
Feeder Tap
- Thread starter Mike01
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- Connecticut
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- Engineer
I would think the general consensus is that your #4 conductors on the load side of the disconnect are tap conductors. They would have to comply with 240.21(B).
However, transformer secondary conductors would not be considered tap conductors by the definition given in Art. 240.
And feeder tap conductors are still considered a feeder. They're just a portion of a feeder that is not properly protected for their ampacity at the point at which they receive their supply.
However, transformer secondary conductors would not be considered tap conductors by the definition given in Art. 240.
And feeder tap conductors are still considered a feeder. They're just a portion of a feeder that is not properly protected for their ampacity at the point at which they receive their supply.
- Location
- Illinois
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- retired electrician
A "feeder tap" can originate at the load side of an OCPD. It does not have to be a tap of an acutal feeder conductor.
kwired
Electron manager
- Location
- NE Nebraska
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- EC
A feeder tap is any conductor that has overcurrent protection that is higher than the ampacity of the conductor, except where allowed to be next standard size up overcurrent device. In the case of motors the rules are a little different, but the conductor is still protected via the combination of short circuit and ground fault protection provided by the branch circuit device and overload protection provided by the motor overload protection device.
Any conductor does not have to be art 310 conductors either. Could be bus, or other assembly, though you may not run into that as often as a tap and not have it be part of a listed assembly.
Any conductor does not have to be art 310 conductors either. Could be bus, or other assembly, though you may not run into that as often as a tap and not have it be part of a listed assembly.
petersonra
Senior Member
- Location
- Northern illinois
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- Semi-retired engineer
Based on this definition, a feeder tap is actually part of the feeder, and not part of the branch circuit.
I have never seen anything that prohibits installation of a disconnecting means in a feeder circuit, or a tap conductor. the tap conductor cannot terminate at a non-fused disconnect, but it can start at one.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Bob brought up a good point that I missed the first time I read the OP.
A feeder tap needs to terminate at an overcurrent device.
Your feeding an unfused disconnect and then tapping again is effectively "tapping a tap" and is not allowed by any of the feeder tap rules.
petersonra
Senior Member
- Location
- Northern illinois
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- Semi-retired engineer
I think based on the OP that he was going to feed the unfused DS with full size conductors and then come out of the DS with smaller conductors which appears to be acceptable as long as the smaller conductors terminate at an OCPD. Although it is not completely clear that is what he is actually doing.
- Location
- Connecticut
- Occupation
- Engineer
That's the way I read it as well.
I think his question is whether or not the lugs on the switch (or c/b) are part of the "feeder."
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
If an unfused switch it needs to be rated at least as much as the feeder in this case.
Each tap will need to end in an overcurrent device, making the need for the unfused switch somewhat unnecessary, but maybe OP has a good reason for the need of this switch.
If the load side of the switch was not tap conductors the lugs would still need to carry the feeder current so I fail to see why they are not part of the feeder. The point at which conductor ampacity is reduced is the start of the tap.
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