Article 368 as it applies to a specific busway product

[Atlantec]

A manufacturing facility currently uses a 60A, 3-pole 300V rated busway product fed with a 60A, 3 pole over current protection device at the panelboard. The facility uses a UL listed 15A, 3-pole, 300V rated non-fused plug-in "jack" which is has (3) brass spring loaded contacts and an integral junction box with (3) #12 conductor leads. The jacks are by the same manufacturer of the busway. They feed manufacturing equipment from these "jacks" using flexible cords with strain reliefs. There are hundreds of these types of equipment connections.

If listing the specific products used is OK with the Forum rules then that might help since this type of busway is not like "most" busway in that it is more of a powered track with multiple non-fused drops to non-fixed equipment.

According to 368.17, a 15A over current protection device appears to be required for these plug-in "jacks"....or is it?

 

[charlie b]

You can post the manufacturer's information, if you think it will help. But my take on the situation is that you do need an overcurrent device at each point that power is taken from the busway using the "jack" you described. Otherwise, you have a #12 wire being protected against overcurrent by a 60 amp breaker, and that is not allowed. 368.17(C) is the specific reference.

Welcome to the forum.

 

[don_resqcapt19]

You can post the manufacturer's information, if you think it will help. But my take on the situation is that you do need an overcurrent device at each point that power is taken from the busway using the "jack" you described. Otherwise, you have a #12 wire being protected against overcurrent by a 60 amp breaker, and that is not allowed. 368.17(C) is the specific reference.

Welcome to the forum.

What about Exception #1? That sends you to 240.21 and the feeder tap rules are in 240.21(B). It appears to me that you can use the feeder tap rules for this application.

 

[Atlantec]

Thanks for the responses so far and I agree with both but its still fuzzy on if it is a feeder tap, branch circuit or other. If it is a feeder tap then we need to take into consideration the length which is greater than 10' but less than 25'. If it is a feeder tap than the conductors would need to be rated at least 1/3 of 60A which is 18A so the #12's are ok. However, these are branch circuit taps which fall under 240.21A. To me, without over current protection then the cord drop becomes the fuse if connected to a piece of equipment rated with an ampacity higher than the #12's can handle.

The specific product is Feedrail/Electrorail FRS100 busway and FRS-53P "jack". They are manufactured primarily for textile manufacturing facilities and are UL listed as busway and busway acessories.

Another tidbit is that this facility has been in operation for many years and is ISO compliant. They are moving to a new building and taking all of the equipment and Feedrail system with them.

 

[GoldDigger]

Is there an overcurrent device (not just overload) at the equipment end? A tap would require that, along with a maximum ratio between bus protection and wire ampacity.
Also, if there is no OCPD downstream, this would be branch wiring, not a feeder.

Tapatalk...

 

[charlie b]

I don't think these are feeders. There are (as I understand it) no overcurrent devices at the equipment. That makes the conductor a branch circuit. Also, if indeed there are no overcurrent devices at the equipment, then the installation does not follow the 10-25 foot tap rule. Also, all o fthe tap rules require physical protection of the conductors, and that is not available for this installation.

 

[Atlantec]

I tried to reply to the post earlier but it didn't show up. Anyway I agree that this is not a feeder tap so at the least it would fall under 240.21A for branch taps.

The product is Feedrail/Electrorail FRS-100 with a FRS-53P "jack". Just talked to manufacturer and they say this is how 90% of the installations are. There must be over current protection on the equipment itself somewhere. I did not observe the details of the equipment connection so this must be how they are getting by with it otherwise there is nothing to protect the branch circuit.

But what protects the cord drop from the busway to the equipment? The only upstream over current device is a 60A 3P breaker.

 

[GoldDigger]

The idea is that, just as for motor circuits, the upstream (60A) breaker will open soon enough in the event of a short circuit, while the OCPD at the equipment (i.e. at the end of the tap) will protect against an equipment fault that causes a current more than 15A, but less than 60.


If you are able to (allowed to) connect more than one device to a single tap, you could overload the tap even then. So this type of system has to be managed, not just randomly added to.

Tapatalk...

 

[Atlantec]

The idea is that, just as for motor circuits, the upstream (60A) breaker will open soon enough in the event of a short circuit, while the OCPD at the equipment (i.e. at the end of the tap) will protect against an equipment fault that causes a current more than 15A, but less than 60.


If you are able to (allowed to) connect more than one device to a single tap, you could overload the tap even then. So this type of system has to be managed, not just randomly added to.

Tapatalk...

While I understand your logic, are we all in agreement that this is a feeder tap falling under 240.21B(2) and not a branch circuit tap or busway tap falling under 240.21A, 368.17C or even 368.56?

If it is a feeder tap, does 240.21B(2) subsection (3) allow flexible cords as an approved enclosure of tap conductors protected from physical damage? I would think not but then again, the code as it applies to this specific situation is all over the place and some sections make no logical sense at all e.g. 240.5B.

 

[don_resqcapt19]

In my opinion the busway is the feeder and the #12s are feeder taps if you don't install OCPD at the busway. If you install OCPD at the busway then the #12s would be branch circuits.

No matter how you look at it the #12s have to be protected. If they are tap conductors they will have the OCPD remote from the busway per one of the 240.21(B) rules. If they are branch circuit conductors, they will have the OCPD at the busway.

The rule in 240.21(B)(2)(3) requires physical protection by a "raceway or other approved means". That leaves it up to the AHJ as to the use of the cord. It could be considered protected if its location is such that physical damage is not likely.

Remember that "we have always done it that way" does not make it code compliant, although that has been successfully used as a substantiation for a code change proposals.