How to Size Conductors, breakers, conduit, meter?

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Prototype1

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Hey guys, I am trying to size the breaker, conductor, conduit and meter. From attached photo #2, I have 50 HP (65A), and 250 HP (302A).

What steps I need to take to find the size of breaker? Conductor? conduit, and meter?

This is my thought process: to how to size it:
1: I went to Article 430.120 – FLC – 65 A * 1.25 = 81.25
2: Table 310.16, look at 75deg C Copper- the AWG at 81.25 Amp is AWG 4.
3: For the breaker; Table 250.122:
4: Ch-9 Table-5: (XHHW) Wire (AWG 4) * 3 = Ans
5: Ch-9 Table- (XHHW) AWG Ground
6: Wire + GND= Answer
7: Ch-9 Table 1: Over 2 conductor: 40%: step 6 answer/ 0.4 =
8: Ch-9 Table 4: RMC article 352-353 –
value close to step 7 (over 2 wires 40%) to get trade size is


Please give your insight. It will be great if you wrote out steps. It will give me more clarity.

Thank you,

Fellow electrical guy.
 

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Prototype1 said:
This is my thought process: to how to size it:
1: I went to Article 430.120 – FLC – 65 A * 1.25 = 81.25
2: Table 310.16, look at 75deg C Copper- the AWG at 81.25 Amp is AWG 4.
3: For the breaker; Table 250.122:
4: Ch-9 Table-5: (XHHW) Wire (AWG 4) * 3 = Ans
5: Ch-9 Table- (XHHW) AWG Ground
6: Wire + GND= Answer
7: Ch-9 Table 1: Over 2 conductor: 40%: step 6 answer/ 0.4 =
8: Ch-9 Table 4: RMC article 352-353 –
value close to step 7 (over 2 wires 40%) to get trade size is
Click to expand...
Can you explain with some more detail what you're looking for in 4-9? Are you trying to find the size of the RMC raceway?
 
You mentioned 430.120.. Is a variable speed drive involved ?
If so, are you sizing conductrs/OCP to the load or the drive supply ?
 
infinity said:
Can you explain with some more detail what you're looking for in 4-9? Are you trying to find the size of the RMC raceway?
Click to expand...
diagram from my post. So, here is what I did:
Branch circuit conductors:
50 HP [FLC= 65A, 65A*125% = 81.25A got Conductor size AWG 4]
250 HP [FLC= 302A, 302A*125% = 377.5A got Conductor size AWG 500MCM table 310.16(75 ,Copper)].

Branch circuit overcurrent device: NEC 430.52(C)(1)
For 50 HP - I am doing 65 A * 250% = 162.5 Amp breaker. But from ugly book, for 50 HP size breaker-150A. For 250 HP - 302 * 250% = 755 A. But the size breaker is 500 A. Should I not go up and standard size of breaker?

Feeder Connectors:
From 250 HP - (125% * 3025A) + 65 (FLC) = 442.5. AWG-700 MCM/ 460A (table 310.16(75, copper column))

Feeder OCD:
250 HP - 500 fuse (302 (FLC)
50 HP - 200 Fuse (65 FLC) ( I got 200 A from ugly book page. 42) But for 50 HP size breaker on page: 40 it is 150 A breaker.

So largest OCD: 500 fuse +65 (FLC) - 565 Amp and that will be 600 Amp (OCD) - table 310.16 AWG 350 MCM/ 310 A (running 2 in parallel).
 
Prototype1 said:
diagram from my post. So, here is what I did:
Branch circuit conductors:
50 HP [FLC= 65A, 65A*125% = 81.25A got Conductor size AWG 4]
250 HP [FLC= 302A, 302A*125% = 377.5A got Conductor size AWG 500MCM table 310.16(75 ,Copper)].

Branch circuit overcurrent device: NEC 430.52(C)(1)
For 50 HP - I am doing 65 A * 250% = 162.5 Amp breaker. But from ugly book, for 50 HP size breaker-150A. For 250 HP - 302 * 250% = 755 A. But the size breaker is 500 A. Should I not go up and standard size of breaker?

Feeder Connectors:
From 250 HP - (125% * 3025A) + 65 (FLC) = 442.5. AWG-700 MCM/ 460A (table 310.16(75, copper column))

Feeder OCD:
250 HP - 500 fuse (302 (FLC)
50 HP - 200 Fuse (65 FLC) ( I got 200 A from ugly book page. 42) But for 50 HP size breaker on page: 40 it is 150 A breaker.

So largest OCD: 500 fuse +65 (FLC) - 565 Amp and that will be 600 Amp (OCD) - table 310.16 AWG 350 MCM/ 310 A (running 2 in parallel).
Click to expand...
You are doing too many things at once. So let's take the first couple steps and then you can do the next one from there. Amperages from table 420.147-150. If your first step is right, your second step is wrong. Overcurrent protection isn't FLC*1.25*250% It is FLC*250%. conductor size is *1.25.
 
Strathead said:
You are doing too many things at once. So let's take the first couple steps and then you can do the next one from there. Amperages from table 420.147-150. If your first step is right, your second step is wrong. Overcurrent protection isn't FLC*1.25*250% It is FLC*250%. conductor size is *1.25.
Click to expand...
I was following Motor branch circuit and feeder example from ugly book page: 42.
 
Update: I got the conductor, conduit, ground size and know how to size them now (Also breaker with help of ugly book) But got still have no idea how to size a breaker properly (still suck at it).
 
Prototype1 said:
Update: I got the conductor, conduit, ground size and know how to size them now (Also breaker with help of ugly book) But got still have no idea how to size a breaker properly (still suck at it).
Click to expand...
one motor. get the FLA from tables 430.147-430.150. The go to 430.52 select the proper column or line and do the math. That simple.
 
Strathead said:
one motor. get the FLA from tables 430.147-430.150. The go to 430.52 select the proper column or line and do the math. That simple.
Click to expand...
more than 1 motor (feeder) 430.62... rating of largest GFSC device (from above) + FLC of other motors or loads
 
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