tapping separate switchboard sections to feed a single load

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petersonra said:
I think we should not use the word tap since these are just normal feeder conductors.


Nice idea but then they would be taps and they are not close enough to meet the tap rules.

Even if there is no room for a new switchboard near the existing one perhaps there is room for some fused disconnects. Then you could potentially tap to them and then feed to the chillers.
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How hard is it to "tap" (not a tap lol) and get 8 sets of 3#500s from a single switchboard?

Here's a pic of 1 for reference:

1695754985560.png
 
synchro said:
Could you have the chillers fed from two lower rated switchboards, and where each of these switchboards is fed by its own section in the main switchboard? That way you could have 4 sets of 3#500 kcmils from each of the two sections, if that would work out.
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petersonra said:
I think we should not use the word tap since these are just normal feeder conductors.

Nice idea but then they would be taps and they are not close enough to meet the tap rules.
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I meant that if the chillers (plural) could be split into two separate loads, then they could each be fed independently by their own switchboard section and their own separate feeder. But maybe the chillers are a packaged system that needs a single feed?
 
synchro said:
I meant that if the chillers (plural) could be split into two separate loads, then they could each be fed independently by their own switchboard section and their own separate feeder. But maybe the chillers are a packaged system that needs a single feed?
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I still don't see how that would help me. I cannot tap and have less than 25 feet because there is no room
 
See 408.3(A)(3), it may be an issue, although it is not entirely clear how the word "intended" plays out.

(3) Same Vertical Section. Other than the required interconnections and control wiring, only those conductors that are intended for termination in a vertical section of a switchboard or switchgear shall be located in that section

edit: read it over a few more times, seems clear that you cant run conductors thru a section that they do not terminate in.
 
wwhitney said:
You left out the exception:

Exception: Conductors shall be permitted to travel horizontally through vertical sections of switchboards and switchgear where such conductors are isolated from busbars by a barrier.

Cheers, Wayne
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Yes, but I am assuming that barrier would be something from the factory. I am skeptical that such a barrier could be added in the field based on typically switch board construction.
 
electrofelon said:
See 408.3(A)(3), it may be an issue, although it is not entirely clear how the word "intended" plays out.

(3) Same Vertical Section. Other than the required interconnections and control wiring, only those conductors that are intended for termination in a vertical section of a switchboard or switchgear shall be located in that section

edit: read it over a few more times, seems clear that you cant run conductors thru a section that they do not terminate in.
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If I tap each section and go up through the crown box, those conductors are still in their respective vertical section without passing through other sections of the switchboard so wouldn't that still be ok?

Maybe I'm not understanding this section of code.
 
I think I just thought of an idea...

The existing 3000A service switch feeds an existing 3000A house switchboard,

I will remove the 3000A feeders serving the 3000A house switchboard, and then use the existing 3000A service switch to feed a new "tap" section with vertical busses (this is essentially a empty switchboard with vertical busses but without any switches). The 3000A house switchboard will be refed using the tap section and then the tap section will also be used to feed the new 3000A switchboard for the chillers

does anyone see anything wrong with this idea?
 
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