# 400 amps breaker fed by fusable 200 amp source.



## weflavien (Jan 10, 2014)

I have a 400 Amps circuit breaker feeds several welding machines.
I need to supply power to the breaker , I have only 200 amps source and have 200 amps fuses , my question is: can I feed the 400 amps breaker with the cable rated for 200 amps and protected by the only the 200 amps fuses? 
Please advice me ?


Thank you.


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## five.five-six (Apr 9, 2013)

weflavien said:


> Please advice me ?
> 
> 
> Thank you.


Nothing you said made sense, hire an electrician and have him tell us what your problems it.


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## weflavien (Jan 10, 2014)

Let me explain it in different way ! 
I have a 3 phase 400 amps circuit breaker, the output of this breaker is feeding 20 welding receptacles.
I need to feed the breaker with power and I only have inside the motor control center 200 amps fused power box.
the distance between the MCC and the 400 amps breaker is aprox. 300 ft.
can I do that? and use cables rated for 200 amps ?

Let me know whats your thoughts.

Thanks,


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## weflavien (Jan 10, 2014)

actually this is what an electrician wants to do , and I think the breaker for the welding receptacles should lowered to 200 amps or 225 , but the electrician is thinking the 200 amps inside the MCC will protect any over-current since its rated for the cables! what do you think?


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## Southeast Power (Jan 18, 2009)

The 400 amp breaker will only be a disconnect and would not be considered an over current device using this design.
300' is a lot to ask of a conductor if it's not properly sized for the voltage drop.
What voltage and current are you expecting to draw from each welder and how many are you expecting to use at one time?


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## weflavien (Jan 10, 2014)

Thanks Jrannis , the total continuous current will be less than 150 amps , I will consider the voltage drop in the cable size. 
the 400 amps circuit breaker will be isolating point ! 
and if I have a fault on any welding machine will take time and more damage to the cable since the 200 amps located in the MCC 300' away.
Is this acceptable or the electrician should install a proper circuit breaker on each end of the cable?!!


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## Speedy Petey (Jan 10, 2007)

As CLEARLY stated when joining, this site is for electrical professionals only. 
Please contact a professional electrician in your area.


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