No. Of ways in panel board schedule

[shujath36]

I used to design the distribution panel board based on the concept shown below. Since the three phases are distributed on both sides simultaneously the total no. of ways end at multiple of six ideally.

Generally 10-20% spare is kept for future purpose. In of my projects, the govt. approving authority commented on my design and asked to reduce the no. Of ways to 22 rather then 24. Even though i corrected it according to their inputs, but could not understand how a three phase distribution of such type can have 22 ways. In such case how can there be balance in the three phases. ? And is it practically possible.? Do panel board manufacturers produce such size of boards.?




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[Smart $]

I used to design the distribution panel board based on the concept shown below. Since the three phases are distributed on both sides simultaneously the total no. of ways end at multiple of six ideally.

Generally 10-20% spare is kept for future purpose. In of my projects, the govt. approving authority commented on my design and asked to reduce the no. Of ways to 22 rather then 24. Even though i corrected it according to their inputs, but could not understand how a three phase distribution of such type can have 22 ways. In such case how can there be balance in the three phases. ? And is it practically possible.? Do panel board manufacturers produce such size of boards.?

If you corrected it, you should already know if manufacturers produce that size. :slaphead:

Or is it that you corrected on paper? :angel:

Anyway, I've run across a couple few odd-number-of-spaces panels before, but not often and I've never been the one ordering them.

What is their reason for wanting to go with a 22-space panel? Certainly, can't be motivated for economic reasons. :happyno:

 

[Smart $]

CONT'D...


The load can be balanced by arranging/rearranging single phase L-L and L-N loads.

Definitely practical and possible, save getting a custom made panelboard. :blink:

 

[infinity]

IMO the number of single pole slots should be divisible by 6 for a 3Ø panelboard. Limiting it to 22 instead of 24 is just dumb.:roll:

 

[iwire]

IMO the number of single pole slots should be divisible by 6 for a 3Ø panelboard. Limiting it to 22 instead of 24 is just dumb.:roll:

:thumbsup:

 

[Fnewman]

Is it possible that they are trying to tell you to supply 22 breakers, leaving two spaces for 'future'?

 

[shujath36]

Is it possible that they are trying to tell you to supply 22 breakers, leaving two spaces for 'future'?

Yeah possible. But we mention SPARE meaning for future purpose. We can't have two engineering languages .

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[Strathead]

Yeah possible. But we mention SPARE meaning for future purpose. We can't have two engineering languages .

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there shouldn't be two languages, but spare means with a breaker in the spot, and space means provision for a future breaker. I don't believe I have seen spare mean for future purpose.

 

[Carultch]

IMO the number of single pole slots should be divisible by 6 for a 3Ø panelboard. Limiting it to 22 instead of 24 is just dumb.:roll:

One of our utilities requires all the spaces filled, and filled with something other than spare breakers or filler blanks, when connecting a PV system on the line side of a service. Apparently they didn't think of the practical implications that panelboards only come in standard qtys of spaces, so you have no course of action when your system only fills part of a standard panelboard.

Apparently the thinking is that if you have a 200A service, and a 200A main panel, that when you add loads on a PV system connected on the line side, that you could in theory draw more than 200A. It would happen when the PV production is zero, the house loads are maximum, and the loads on the PV system are significant. Total Murphy proofing rule of a situation that will seldom happen in practice.