Question 240.21(B)(2)

[david luchini]

So what is considered tap? From the def would the 400 amp at the end were to be removed would it result in tap?

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From the wireway to the 400A fused switch is a tap.

Removing the 400A fused switch at the end has no effect on the tap.

 

[ActionDave]

I thought i did says 1200 amps.

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Whatever you though, clearly what you said is..

There are 2 fused disconnects one protecting OCPD 400 amps and the other 400 amps terminating at end of tap conductors.

I have to check regarding less than 25 feet or 25ft to 100ft.

Here's a pro tip, hit Preview Post and proofread what you typed. For whatever reason it's easier to see your mistakes when the formatting changes.

 

[ActionDave]

So what is considered tap? From the def would the 400 amp at the end were to be removed would it result in tap?

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You have to have overcurrent protection on your wires. 95% of the time you have to have to have it wher the circuit originates... a panel has a 400A breaker in it and 400A conductors are landed in said breaker and go out to a 400A piece of electrical gear, maybe a really big dog walker, maybe it feeds another building, whatever...

5% of the time the code allows you to put your overcurrent protection farther downstream....a 1200A buss is tapped with 400A conductors that go to 400A fused disconnect or main breaker panel, then it can go on to feed whatever .....

 

[kwired]

Size of OCPD is 1200 amps peotrcting wireway.

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Even if not intentional you misled us at first - most thought you were extending off a circuit already protected at 400 amps - that would not be a feeder tap.

If you have 1200 amp circuit and wish to make a 400 amp extension off of it - that is one situation where these tap rules apply.

for the 25 foot rule you must comply with all the three conditions in the section you asked about (code content in blue)


1. The ampacity of the tap conductors is not less than one-third of the rating of the overcurrent device protecting the feeder conductors. Since feeder overcurrent protection is 1200 amps ampacity of your tap conductor must be at least one third of that - so it must be a 400 amp conductor, you got lucky as your wanting a 400 amp tap, but if you were tapping to a 200 amp device and were over 10 but less then 25 feet long you would have still needed at least 400 amp conductor here.


2. The tap conductors terminate in a single circuit breaker or a single set of fuses that limit the load to the ampacity of the tap conductors. This device shall be permitted to supply any number of additional overcurrent devices on its load side. Your 400 amp device at the end of the tap meets this requirement - you could not feed say two 200 amp devices with this tap - has to be a single device.


3. The tap conductors are protected from physical damage by being enclosed in an approved raceway or by other approved means.

Inspector could approve other means, but for most part this says must be in a raceway. It can't be in a cable wiring method.

 

[jap]

So what is considered tap? From the def would the 400 amp at the end were to be removed would it result in tap?

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Your only actual tap conductors are where you are going to tap into the 1200 amp conductors in the wireway to feed the line side of the 1st 400 amp fused disconnect located at the wireway.

I'm curious as how your going to do this since I invision (3) parallel sets of conductors in this wireway coming from the 1200 amp OCPD, along with the 3 or 4 tap conductors your bringing into it, before you ever get started.

You may be considering Polaris connectors, power distribution blocks, or the like to make this connection but that's going to be fun and ugly, but, that's really none of my business.

The wire from the load side of the 1st 400 amp fused disconnect to the line side of the 2nd 400a disconnect is a feeder.
Not sure why your feeding a fused disconnect with a fused disconnect, but, that's really none of my business either.

JAP>

 

[jap]

I'd be calling the supply house for a price on a 1200 amp Main lug only panel with a 400 amp branch breaker in it to take the place of that gutter and save a lot of heartache.

 

[kwired]

Your only actual tap conductors are where you are going to tap into the 1200 amp conductors in the wireway to feed the line side of the 1st 400 amp fused disconnect located at the wireway.

I'm curious as how your going to do this since I invision (3) parallel sets of conductors in this wireway coming from the 1200 amp OCPD, along with the 3 or 4 tap conductors your bringing into it, before you ever get started.

You may be considering Polaris connectors, power distribution blocks, or the like to make this connection but that's going to be fun and ugly, but, that's really none of my business.

The wire from the load side of the 1st 400 amp fused disconnect to the line side of the 2nd 400a disconnect is a feeder.
Not sure why your feeding a fused disconnect with a fused disconnect, but, that's really none of my business either.

JAP>

Good point to bring up. If the 1200 amp feeder is three conductors in parallel, one must tap into all three of the set, they are only a 1200 amp conductor as a set, can't tap into just one conductor of each set.