Transformer Secondaries (Again)

[Mike01]

Attached is an image from some manufacturers literature it indicates a transformer with a secondary conductor of 500Kcmil, and a tap of that conductor to a #1 to a disc. Sw. to the load. My question is the xfmr. Secondaries are considered taps. I thought you could not tap a tap? Is the application in this image a correct installation? what if he used 500?s to the disc. By keeping the conductors the same size would it still be considered a tap?

 

[iwire]

You are correct, you can not tap a tap even if you keep all the conductors the same size.

 

[augie47]

Bob, If its a 500 kcmil connected to a 500 kcmil is that considered a "tap". Doesn't seem to meet the definition in 240.2

 

[RUWired]

Bob, If its a 500 kcmil connected to a 500 kcmil is that considered a "tap". Doesn't seem to meet the definition in 240.2

The idea is that transformer tap conductors can not extend or leave the enclosure that it supplies.

Rick

 

[don_resqcapt19]

Bob, If its a 500 kcmil connected to a 500 kcmil is that considered a "tap". Doesn't seem to meet the definition in 240.2

Actually it does meet that definition. The conductor connected to the transformer is not protected at or below its ampacity. Neither is the conductor connected to the first conductor, no matter what size it is. Even a connection of larger conductor would be tapping a tap in this case.

 

[Pierre C Belarge]

Bob, If its a 500 kcmil connected to a 500 kcmil is that considered a "tap". Doesn't seem to meet the definition in 240.2

I do not see where it says a tap conductor cannot be spliced, as long as it conforms with the particular tap rule being referenced.


Splicing and tapping are two different topics...

 

[jim dungar]

There is a definition of "tap" in 240.2 for a reason. The NEC is specifically saying that not all connections are "taps" even though our industry calls them that name.

In the OP there would be nothing wrong with supplying two lugs on the transformer lug pads. This provides two (2) individual sets of secondary conductors.

 

[Pierre C Belarge]

There is a definition of "tap" in 240.2 for a reason. The NEC is specifically saying that not all connections are "taps" even though our industry calls them that name.

In the OP there would be nothing wrong with supplying two lugs on the transformer lug pads. This provides two (2) individual sets of secondary conductors.

It is correct to say one can supply two sets of secondary conductors, or more if necessary.
Those secondary conductors (as per 240.21(C) are treated as "tap" conductors.

 

[Smart $]

Actually it does meet that definition. The conductor connected to the transformer is not protected at or below its ampacity. Neither is the conductor connected to the first conductor, no matter what size it is. Even a connection of larger conductor would be tapping a tap in this case.

What about a primary protected secondary? Would that not make the secondary conductors feeders (i.e. not taps)?

 

[iwire]

I do not see where it says a tap conductor cannot be spliced, as long as it conforms with the particular tap rule being referenced.


Splicing and tapping are two different topics...

A conductor leaving a transformer is a tap conductor and must terminate in one over current device, not two or more.