480 v machines

[mike90040]

Hi, I am doing some work and I have a row of 10 machines. Each machine draws 21 amps @480v. I want to feed them using a 1 1/4 conduit to a 16x16 pull can and feed each machine with a 1/2 conduit to the disconnect at the machine. Is that up to snuff per code or is there something I'm missing?

 

[George Stolz]

How many current carrying conductors in that 1.25" conduit?
What size?

 

[mike90040]

Ok here goes...start with a 200 amp 3 ph 480v panel. each machine is 3ph 480v 21amp. I'm thinking if I run a 1 1/4 conduit to a 18x18 pull box an come out of the pull box to each machine with 3 # 10 an ground I could use 1/2 pipe. Make sense ?

 

[ohmhead]

Ok here goes...start with a 200 amp 3 ph 480v panel. each machine is 3ph 480v 21amp. I'm thinking if I run a 1 1/4 conduit to a 18x18 pull box an come out of the pull box to each machine with 3 # 10 an ground I could use 1/2 pipe. Make sense ?

Well 10 x 21 amps = 210 amps = bad news

1 1/4 PIPE =TOTAL[ WIRE THWN 10] #=29 # = bad news

Now derate over 3 or more you have wires 10x3 = 30 total derate is 45 % = bad news

Table 310-16 says 10 wire =35 amps 75deg 35 amps x 45 %= =15.75 amps each circuit . = bad news


It doesnt look good .

 

[augie47]

How do you plan on protecting each machine (what overcurrent device ? - located where ?)
Will the #10 s be taps ? If so, how long ?
It is possible for every machine to be operating at one time ?

 

[DAWGS]

I would suggest running seperate conduits for each circuit/machine. Because how you have it planned aint gonna work. Also like ohmhead said you may want to load calc for the panel if all these machines will be running at the same time.

 

[LarryFine]

Mike, can you place a sub-panel anywhere around where you thought of placing the J-box?

 

[weressl]

Hi, I am doing some work and I have a row of 10 machines. Each machine draws 21 amps @480v. I want to feed them using a 1 1/4 conduit to a 16x16 pull can and feed each machine with a 1/2 conduit to the disconnect at the machine. Is that up to snuff per code or is there something I'm missing?

Sounds like an ideal cable tray job to me..... But hey, if you are a hammer everything looks like a nail.....:grin:

 

[LarryFine]

... if you are a hammer everything looks like a nail.....:grin:

Laszlo the Hammer. Sounds like a pro wrestler. :grin:

 

[mike90040]

480v machines

480v machines

Thank You all who responded, will go back to drawing board as far as piping. Not all machines will be running at the same time and there is a second 480v panel board. There will also be a disconnect on each machine. Two key factors I left out. I really appricate You All who took the time to respond.
Mike

 

[weressl]

Laszlo the Hammer. Sounds like a pro wrestler. :grin:

MMA, UFC, K2, WCF.... Pro Wrestling is SOOOO yesterday.....

 

[augie47]

Thank You all who responded, will go back to drawing board as far as piping. Not all machines will be running at the same time and there is a second 480v panel board. There will also be a disconnect on each machine. Two key factors I left out. I really appricate You All who took the time to respond.
Mike

If there is a (fusible) disconnect at each machine you might want look at a 200 amp feeder with taps per 240.21.