# Feeder sizing for machine



## Handasee (Dec 18, 2009)

Woodworking machine built in Italy.
The machine nameplate states:28Kw, 55 amps at 600 volts.
If this was a motor (28Kw= 28000/746=37.5HP), I would feed this machine with a #6AWG. (37.5HP at 600 volts would draw approximately 38 amps.) 
For this machine to be labelled 55 amps, then the efficiency X PF must be in the order of 0.49. This is my calculation. Nothing in the machine manual gives any information on efficiency or power factor. 
If I go by the nameplate then I must run a #4 awg feed. My experience tells me that this will be overkill. Italian machines that I have seen overstate the amperage. 
I would like some opions on how others would feed this machine.


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## wildleg (Apr 12, 2009)

does it state 50 or 60hz ?


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## Handasee (Dec 18, 2009)

Machine is 60 Hz.


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## captkirk (Nov 21, 2007)

I used to work for a contractor that would size RTU's by the Max breaker size....No kidding... Nothing says overkill more than runing 1/0 for a 30 amp 480 volt unit..


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## Bkessler (Feb 14, 2007)

captkirk said:


> I used to work for a contractor that would size RTU's by the Max breaker size....No kidding... Nothing says overkill more than runing 1/0 for a 30 amp 480 volt unit..


I hope the bozo at least pulled aluminum.


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## RIVETER (Sep 26, 2009)

Handasee said:


> Woodworking machine built in Italy.
> The machine nameplate states:28Kw, 55 amps at 600 volts.
> If this was a motor (28Kw= 28000/746=37.5HP), I would feed this machine with a #6AWG. (37.5HP at 600 volts would draw approximately 38 amps.)
> For this machine to be labelled 55 amps, then the efficiency X PF must be in the order of 0.49. This is my calculation. Nothing in the machine manual gives any information on efficiency or power factor.
> ...


Why are you worrying about overkill? If the nameplate calls for it...just do it.


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## Handasee (Dec 18, 2009)

This customer has been with me for over 20 years. Its a matter of trust.
He knows that any job I do for him will be a fair price. His last contractor installed material that could not be justified by code or price.


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## RePhase277 (Feb 5, 2008)

You need to upsize the conductors by 125%, at least according the NEC. Is it the same for Canada?


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## RIVETER (Sep 26, 2009)

Handasee said:


> This customer has been with me for over 20 years. Its a matter of trust.
> He knows that any job I do for him will be a fair price. His last contractor installed material that could not be justified by code or price.


If he has been a customer for 20 years, why did he have a "LAST" contractor?


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## Handasee (Dec 18, 2009)

Same thing in Canada for motors. Largest motor is 1.25xFLA + addition of FLA of each additional motor on the feeder. 
Problem is that if I add up the motors in the machine it does not add up to 55 amps.


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## Handasee (Dec 18, 2009)

RIVETER said:


> If he has been a customer for 20 years, why did he have a "LAST" contractor?


I'm still fixing the problems created by the "last" contractor


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## RIVETER (Sep 26, 2009)

Handasee said:


> I'm still fixing the problems created by the "last" contractor


Was his last contractor 20 years ago?


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## Handasee (Dec 18, 2009)

RIVETER said:


> Was his last contractor 20 years ago?


That's right.


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## RIVETER (Sep 26, 2009)

Handasee said:


> That right.


Maybe I am misunderstanding, but are you saying that you are still correcting problems from 20 years ago?


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## wildleg (Apr 12, 2009)

which NRTL is the machine labelled with ?


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## Handasee (Dec 18, 2009)

RIVETER said:


> Maybe I am misunderstanding, but are you saying that you are still correcting problems from 20 years ago?


Yes, I'm still finding problems.


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## Handasee (Dec 18, 2009)

wildleg said:


> which NRTL is the machine labelled with ?


NRTL is an American terminology. Could you explain the abbreviation?


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## wildleg (Apr 12, 2009)

national recognized testing laboratory (UL, ETL, etc). my reason for asking is that in the US if it is not listed and labeled it is generally not acceptable with the local authority (AHJ). Also, I was wondering why you would not wire it according to the label that it does have, since you are putting liability onto yourself.


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## Handasee (Dec 18, 2009)

wildleg said:


> national recognized testing laboratory (UL, ETL, etc). my reason for asking is that in the US if it is not listed and labeled it is generally not acceptable with the local authority (AHJ). Also, I was wondering why you would not wire it according to the label that it does have, since you are putting liability onto yourself.


Machine is CSA approved. Same as UL.
Customer has a 60 amp #6 line available, simple one day job. If I must go to a 80 amp #4 line then we are looking at installing a new 600 volt panel in the main electrical room. There is no room to just add a disconnect. 
I have on two occations when applying for approval discussed the labelling of European machines with the CSA inspector and after reviewing the complete schematics, the inspector reduced the current rating labelled on the nameplate.


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## noarcflash (Sep 14, 2011)

I work extensively with Italian machinery. Most are way over stated. And I have pulled heavy wire for no reason, due to name plate ratings.

Most are VFD controlled motors.

My new method is to do a temporary connection, and AMP out all 3 legs, and make a proper judgement.

I used a roll of #6, could have easily gotten away with #8's with head room.


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