Tap Rules, multiple conductors tapped to a larger conductor

[jaggedben]

I'm curious how people think the tap rules in 240.21(B) would apply to the following situation. I recently surveyed a site with an old electrical service that was configured more or less as follows...

400A fused disconnect as service equipment...
400A conductors go from service disco to a tap box...
In the tap box, the 400A conductors end, but are tapped to several sets of conductors feeding other disconnects and load centers...
Let's say* those other conductors are as follows:

• A set of 200A conductors to a 200A fused disconnect that supplies a remote load center
• A set of 100A conductors to a 125A load center with a 100A main breaker
• A set of 150A conductors to a 150A breaker enclosure than supplies a remote load center

All of the equipment mentioned is within 10' of each other.

In your opinion, would this type of arrangement generally be a violation, or not?

Let me clarify that I haven't reviewed the rules to confirm whether each of the three sets would be considered an allowable tap on its own. I'm more interested in the general question of whether multiple sets of conductors can be tapped to one larger set under the rules. But the example could also serve as fodder for discussing whether only certain combinations would be permissible, if that's what people think.

(* In reality, some of the conductors lacked proper overcurrent protection for a tap or for their ampacity, but I'm trying to simplify.)

 

[iwire]

400A fused disconnect as service equipment...
400A conductors go from service disco to a tap box...
In the tap box, the 400A conductors end, but are tapped to several sets of conductors feeding other disconnects and load centers...
Let's say* those other conductors are as follows:

• A set of 200A conductors to a 200A fused disconnect that supplies a remote load center
• A set of 100A conductors to a 125A load center with a 100A main breaker
• A set of 150A conductors to a 150A breaker enclosure than supplies a remote load center

All of the equipment mentioned is within 10' of each other.

In your opinion, would this type of arrangement generally be a violation, or not?

Assuming correct use of listed wire connectors I don't see any violation in your example.

 

[electricalist]

Image 1 is split 200 amps to the left and nsi type 4 space connectors with 1 space for another tap.
2 is tapped to 3 200 amp panels inside garage.
3 all are fed from meter to each disconnect. This method to me is the better of the three . Although not always possible .others will be able to explain how and why each set up may occur . Fused properly all 3 are accepted

 

[augie47]

I agree with Iwire.
As long as your conductors from your 400 amp switch are full size, you simply have 3 taps.