NEW one on me!!

[Jason Rogers]

Good afternoon all, I have a unique electrical question for any industrial guys. I have a customer relocating two 600a 480v presses into a new facility with an existing 1200a breaker in the new switch gear. Both Machines will be running at the same time--- they are over 25ft apart--- and the conductors are rated for 600a. it is my understanding that the OCPD will determine the wire size not load of the two machines. Is there a way to run both the machines off 1 1200 circuit breaker using the existing 600a conductors? Code ref? thanks for any help given

 

[augie47]

Each press would have to be protected by the appropriate overcurrent device as determined by the machine manufacturer or the appropriate NEC Article.
If each press has a 600 amp overcurrent device and disconnecting means it is possible to feed those devices from your 1200 amp breaker with conductors rated less than 1200 amps. I would suggest reviewing 240.21 to see if your situation fit any of those tap rules or, if the facility qualifies, you could use 240 Part VIII, Supervised Industrial Installations.
Reading between the lines in your original post, I am pessimistic you can meet either but the devil is in the details such as the length of the taps (as opposed to distance apart for the equipment)

 

[Jason Rogers]

Thanks For the help.

Thanks For the help.

Thanks for the help. :thumbsup:

 

[renosteinke]

I would be very surprised if these machines did not have control panels, including local circuit breakers and fuses. If that is the case, you might be able to apply tap rules to the feeders.

 

[jap]

If you meant to say that both machines were more than 25' from the 1200 Amp breaker, I think your going to be hard pressed to find any tap rule that will allow you to feed the 600 Amp Machines with 600 Amp rated wiring rom a 1200 Amp breaker,regardless of wether they have Overcurrent Protection in the Controllers or not. Seems like a 1200 Amp MLO Panelboard with 2 600 Amp Feeder Breakers or 2 600 Amp Fused disconnects tapped close to the 1200 Amp breaker might be the better ticket.
Both very pricy Options.

JAP.

 

[SG-1]

If the OCPD is external to the breaker ( as with an ANSI breaker, not molded case ) it may be possible to bifurcate the feeder. Meaning one set of conductors is routed through a set of CTs that are connected to an OCPD. The other set of conductors is routed through a second set of CTs that are connected to a second OCPD. Both OCPDs trip the same 1200 feeder breaker.