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Is there a violation of NEC to change a 200amp main breaker to a 100 breaker?

Is there a violation of NEC to change a 200amp main breaker to a 100 breaker?

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  #1  
Old 01-13-11, 04:44 PM
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Is there a violation of NEC to change a 200amp main breaker to a 100 breaker?

I realize people are usually asking if they can go in the opposite direction,
here's the scenario,
there is an existing 200 amp panel in place. there is a new 100 amp comercial panel installation.

the local utility , PG&E, has stated that doing a new drop to the lovcation is acctually 300 amps, 200 res.+ 100comm.= 300amp, and they would have to change out the transformer and would cost the owner at least 5000.00.
But if we can change out the main breaker in the residential panel to a 100amp then we only have 200amp total and a transformer 'MAY' not be required.
and they would only charge 4999.99)..joke

Would this be a code violation? ( this will be inspected by city and utility..btw)

my thoughts: would not think it would be a violation, so as long as the 100 amp breaker was the proper fit and attached in the same way. not sure if the thickness of the buss bars would be a large factor or not..

thanks for any help, advise.
 
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  #2  
Old 01-13-11, 04:48 PM
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Some panel brands will allow for different size main breakers to be installed.

What is the calculated load for the two usages.

Here the cost of an infrastructure upgrade would be handled by the power company, not the consumer.
 
  #3  
Old 01-13-11, 05:04 PM
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loads are fairly low.

yes I remember when the utility would do a new service drop and there was a 103.00 charge..split over 3 months, not you must Prove you absolutely need a new drop now.. here is the load calc., note PG$E will only allow a 30 amp welder on a commercial or residential panel if the drop is not 3Phase. ( initial surge on transformer)
so basically that means you can only use, a very small plug into the wall welder.. ( 20 amps ) PG$E wanted to see a full list of all equipment to be used with all specs.
3200 SQ. feet home ( 3200 SQFT x 3 VA = 9600VA )
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

general lighting and recepttacle load: 9600VA

small appliance load... 3000
laundry washer 1500
clothes dryer 3000

fixed appliances, dish/ disp 2567

3.5 ton A/c unit 5088 VA




residence total load factor: 25755VA



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
buisness load factor estimate

welder 60 amp 240v 14,400VA ( VA = volt amps )

recepticals 2 @ 1500 VA 3,000VA

lighting: 1 @ 1500VA 1500VA

Commercial total load factor 18900VA


total load factor for panel

43,655VA or 43.6Kva
 
  #4  
Old 01-13-11, 05:29 PM
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How much will the welder be used per day?
 
  #5  
Old 01-13-11, 05:40 PM
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you mean the 20 amp welder?

maybe 2 hours use a day at the peek., I was told they measure every pieces of equipment for the full 100% 'constant on the load.

but to come back to center square, is changing the breaker a code violation?
 
  #6  
Old 01-13-11, 05:51 PM
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No, as long as you follow the directions and use the correct parts.
 
  #7  
Old 01-13-11, 07:05 PM
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thank you pcboss!

.. now i just need to locate that exact breaker type in 100amp.
 
  #8  
Old 01-14-11, 07:11 AM
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If the mfr doesn't make a 100A main breaker for the panel, you may be able to backfeed a 100A branch circuit breaker as long as it is a bolt-on or held down with a retainer clip.
 
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