Feeder "taps" not actually "tapped"?

[hitehm]

It seems anytime you see images online of "feeder taps" like the example attached , they always show conductors physically tapped (spliced) onto feeder wires that have OCPD protection from the upstream source. But what if the feeders are connected straight off the MSP bus (using a lug kit or similar) with no OCPD protection at their source? Is this feeder now considered a feeder "tap" and subject to all the tap rules from 240.21B? It seems to possibly fit the definition of "Tap Conductor" in 240.2 but I'm not sure if this is actually considered a "tap"? I guess another way of asking is: Can a feeder be both a feeder and a feeder tap simultaneously by definition? I am dealing with this exact situation having feeders connected with lugs off the MSP and need to know how to size my wires.

 

[infinity]

IMO they're still tap conductors so the tap rules apply.

 

[xformer]

IMHO any conductor that receives energy without any OCPD at the point of supply is considered a tap conductor.

 

[GoldDigger]

The critical part of the definition of a tap is that the conductors are not protected at their rated ampacity by an upstream overcurrent device.

As a side note, since the tap must terminate at an OCPD, we cannot say of a feeder tap that it can be simultaneously both a feeder and a branch circuit. That argument can be made for an ordinary feeder conductor.


P.S. And, yes, a feeder tap is also a feeder conductor and is subject to both sets of rules (except for the OCPD parts).

P.P.S A feeder originating from a double lugged panel input or from anywhere the bus, including tap kits and feedthrough terminals, on an MLO panel could be a tap conductor. It is just tapped off the bus rather than off the feeder wire.

 

[GoldDigger]

IMHO any conductor that receives energy without any appropriately sized OCPD at the point of supply is considered a tap conductor.

FIFY
Although service conductors also fit your defintion but are not considered tap conductors by the NEC.

 

[jap]

It seems anytime you see images online of "feeder taps" like the example attached , they always show conductors physically tapped (spliced) onto feeder wires that have OCPD protection from the upstream source. But what if the feeders are connected straight off the MSP bus (using a lug kit or similar) with no OCPD protection at their source? Is this feeder now considered a feeder "tap" and subject to all the tap rules from 240.21B? It seems to possibly fit the definition of "Tap Conductor" in 240.2 but I'm not sure if this is actually considered a "tap"? I guess another way of asking is: Can a feeder be both a feeder and a feeder tap simultaneously by definition? I am dealing with this exact situation having feeders connected with lugs off the MSP and need to know how to size my wires.


View attachment 2560720

If I'm understanding you correctly, if there's no OCPD ahead of what you are tapping, then you'd be dealing with a Service Conductor Tap.

JAP>

 

[infinity]

IMHO any conductor that receives energy without any OCPD at the point of supply is considered a tap conductor.

Even if they're sized to greater than or equal to the size of the OCPD?

 

[xformer]

FIFY
Although service conductors also fit your defintion but are not considered tap conductors by the NEC.

I stand corrected Sir.

 

[hitehm]

If I'm understanding you correctly, if there's no OCPD ahead of what you are tapping, then you'd be dealing with a Service Conductor Tap.

JAP>

Hey JAP, sorry I'm not sure what you mean by "ahead of what your tapping". Ahead of seams to mean "in front of" which seems to imply downstream, which the feeder IS protected by at the subpanel. The only protection of the feeder upstream (what I would call "behind" the point of tap) is the main panels Main Breaker. Also, I've haven't heard of an official NEC definition of "Service Tap Conductor". Please clarify, Thanks.

 

[hitehm]

The critical part of the definition of a tap is that the conductors are not protected at their rated ampacity by an upstream overcurrent device.

As a side note, since the tap must terminate at an OCPD, we cannot say of a feeder tap that it can be simultaneously both a feeder and a branch circuit. That argument can be made for an ordinary feeder conductor.


P.S. And, yes, a feeder tap is also a feeder conductor and is subject to both sets of rules (except for the OCPD parts).

P.P.S A feeder originating from a double lugged panel input or from anywhere the bus, including tap kits and feedthrough terminals, on an MLO panel could be a tap conductor. It is just tapped off the bus rather than off the feeder wire.

Ok but you specifically mentioned tapped from an MLO panel and this case is NOT tapped from an MLO panel, it's tapped of the MSP which has a Main Breaker. Does your statement still hold true for a protected bus panel? Because this is exactly the clarity I was looking for. Basically, is the "bus" essentially the same as the feeder conductors when it comes to "taps"?

 

[GoldDigger]

Ok but you specifically mentioned tapped from an MLO panel and this case is NOT tapped from an MLO panel, it's tapped of the MSP which has a Main Breaker. Does your statement still hold true for a protected bus panel? Because this is exactly the clarity I was looking for. Basically, is the "bus" essentially the same as the feeder conductors when it comes to "taps"?

The bus is protected by the main breaker. If the conductors are protected against both short circuit and overload by the main breaker size, then the conductors are not taps. If, on the other hand, the conductors are, say, 50 A conductors and the main is 200 A, then it would be a tap off the bus. It would be subect to length constraints and must terminate on a 50 A or smaller OCPD.

Since a tap must terminate on a breaker, we cannot have the situation where the wiring to a motor is considered protected against overload by the motor overload protection and the breaker only needs to provide short circuit and ground fault protection. The OCPD at the end of the tap must protect against all three.

 

[hitehm]

The bus is protected by the main breaker. If the conductors are protected against both short circuit and overload by the main breaker size, then the conductors are not taps. If, on the other hand, the conductors are, say, 50 A conductors and the main is 200 A, then it would be a tap off the bus. It would be subect to length constraints and must terminate on a 50 A or smaller OCPD.

Since a tap must terminate on a breaker, we cannot have the situation where the wiring to a motor is considered protected against overload by the motor overload protection and the breaker only needs to provide short circuit and ground fault protection. The OCPD at the end of the tap must protect against all three.

Ahh - OK, your example seems to clarify if I understand you correctly - what really defines a conductor as a "tap" is not necessarily if there is any upstream protection at the point of supply, it's whether or not ANY upstream protection, including the bus protection it derives from, is suitable to protect the feeder conductors. If it IS, then they are feeders but not feeder taps, if NOT, then they are BOTH. And just to be clear, I assume this is regardless of overload protection which my situation is not applicable (no motor loads).

 

[electrofelon]

I believe some time ago, someone submitted a proposal to add wording saying (something like) " the tap conductors shall be permitted to connect directly to the device terminals". The proposal was rejected as being not necessary. So yes, you do not need to actually tap an existing feeder conductor.

 

[don_resqcapt19]

Ahh - OK, your example seems to clarify if I understand you correctly - what really defines a conductor as a "tap" is not necessarily if there is any upstream protection at the point of supply, it's whether or not ANY upstream protection, including the bus protection it derives from, is suitable to protect the feeder conductors. If it IS, then they are feeders but not feeder taps, if NOT, then they are BOTH. And just to be clear, I assume this is regardless of overload protection which my situation is not applicable (no motor loads).

That is why the definition says:

Tap Conductor.
A conductor, other than a service conductor, that has overcurrent protection ahead of its point of supply that exceeds the value permitted for similar conductors that are protected as described elsewhere in 240.4.

 

[hitehm]

That is why the definition says:

Tap Conductor.
A conductor, other than a service conductor, that has overcurrent protection ahead of its point of supply that exceeds the value permitted for similar conductors that are protected as described elsewhere in 240.4.

Man.. sorry to beat this to death but does "ahead of" in the NEC mean upstream or downstream of whatever they are referring to? I always get this confused because "ahead of" me is something "in front" of me moving in the same direction, which you would think means downstream. If so, then the protection "ahead of" the tap conductors is the OCPD where the taps terminate, correct?

 

[infinity]

If so, then the protection "ahead of" the tap conductors is the OCPD where the taps terminate, correct?

No, upstream or ahead of protection would be at the origin of the feeder.

 

[hitehm]

No, upstream or ahead of protection would be at the origin of the feeder.

Simply stating "before" its point of supply would be a lot less ambiguous, but ambiguous is what the NEC does best. Thanks for clearing it up all the same, it makes more sense now. I assume also in GoldDigger's example with the MLO panel, which would supply NO OC protection at all to any feeders tapped off it's bus, then NO OCPD certainly "exceeds" the value permitted for similar conductors in 240.4. Although I guess if you continue upstream beyond the MLO panel you will eventually hit an OCPD that would most likely exceed the ampacity of the feeders, giving them the definition of a tapped conductor.

 

[GoldDigger]

Ahh - OK, your example seems to clarify if I understand you correctly - what really defines a conductor as a "tap" is not necessarily if there is any upstream protection at the point of supply, it's whether or not ANY upstream protection, including the bus protection it derives from, is suitable to protect the feeder conductors. If it IS, then they are feeders but not feeder taps, if NOT, then they are BOTH. And just to be clear, I assume this is regardless of overload protection which my situation is not applicable (no motor loads).

Yup!
The confusion comes when someone uses the common English sense of a tap being a T connection of a wire to an existing wire in mid span. To the NEC that is not necessarily a tap, and is not the only way an NEC tap can be created.

 

[jap]

Hey JAP, sorry I'm not sure what you mean by "ahead of what your tapping". Ahead of seams to mean "in front of" which seems to imply downstream, which the feeder IS protected by at the subpanel. The only protection of the feeder upstream (what I would call "behind" the point of tap) is the main panels Main Breaker. Also, I've haven't heard of an official NEC definition of "Service Tap Conductor". Please clarify, Thanks.

The way I read it I thought you may have been considering tapping ahead of the Main Breaker in the panel by the description, which would not be tapping a feeder, it would have been tapping Service Conductors.

Quote "(are connected straight off the MSP bus (using a lug kit or similar) with no OCPD protection at their source?)

JAP>

 

[Strathead]

I don't know if I am misinterpreting your question, but bus is a conductor, so you are tapping a conductor with a conductor.