# 200 Amp Sub



## user5941 (Mar 16, 2009)

I am not sure what your question is but nothing is wrong with the installation


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## electricista (Jan 11, 2009)

leland said:


> I've seen it before but until just now never gave it a serious thought.
> 
> 200 A service, a sub panel added for more ckts only. Everything is in order load wise.
> 
> ...


If I understand you correctly you are asking whether a 100 amp breaker can feed a 200 amp MB panel. Is this correct?

I see no problem with it at all.


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## leland (Dec 28, 2007)

electricista said:


> If I understand you correctly you are asking whether a 100 amp breaker can feed a 200 amp MB panel. Is this correct?
> 
> I see no problem with it at all.



Yes my exact question. just something never seemed right about it. The brain said logically it's fine. The Electrical pro said 'I won't do it'.


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## william1978 (Sep 21, 2008)

I see nothing wrong with it.


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## brian john (Mar 11, 2007)

NO different then installing a MLO sub except you have a disconnect ion the sub in this case.


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## electricista (Jan 11, 2009)

leland said:


> Yes my exact question. just something never seemed right about it. The brain said logically it's fine. The Electrical pro said 'I won't do it'.



Think of it this way. If there were no breaker but main lugs rated at 200 amps you would have no issue with it. The breaker may trip due to a short circuit but overload will be covered by the 100 amp breaker thus protecting the wire.


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## frenchelectrican (Mar 15, 2007)

Leland.,

I did see that few time and there is no issue with that setup at all.

I done that from time to time it more common than you think espcally in large redentail area.

Merci,Marc


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## perry1 (Mar 18, 2009)

leland; now you can buy a 84 circuit/space panel. to take care that problem. perry


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## frenchelectrican (Mar 15, 2007)

perry1 said:


> leland; now you can buy a 84 circuit/space panel. to take care that problem. perry


 
That will only affect if your state do take in 2008 NEC code but on 2005 or before no it will not allowed.

Merci, Marc


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## leland (Dec 28, 2007)

Strange how the code cycle works.
Some things you can bring up to '08,and some you cannot.


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## perry1 (Mar 18, 2009)

frenchelectician; what happen between 2005 & 2007.364 perry


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## frenchelectrican (Mar 15, 2007)

perry1 said:


> frenchelectician; what happen between 2005 & 2007.364 perry


 
Le mot clef entier les numéros de Max de circuits dans la boîte d'interrupteur. Le vieux code dit 42 le nouveau dit 84.

(The whole key word the max numbers of circuits in the breaker box. The old code say 42 the new one say 84.)

Merci,Marc


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## JohnJ0906 (Jan 22, 2007)

frenchelectrican said:


> (The whole key word the max numbers of circuits in the breaker box. The old code say 42 the new one say 84.)
> 
> Merci,Marc


Marc, there is no longer any maximum per the NEC. 408.36 (see exception 2)


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## iamcarbman (Jan 15, 2009)

Is it proper to use a 200AMP sub coming off of a 200AMP main? (customer wants to add pole barn to his home and wants to install welders)


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## JohnJ0906 (Jan 22, 2007)

iamcarbman said:


> Is it proper to use a 200AMP sub coming off of a 200AMP main? (customer wants to add pole barn to his home and wants to install welders)


What does the load calculation say? Is the 200 amp main enough for everything?


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## electrictim510 (Sep 9, 2008)

I personally try to stray from installing a huge panel comparative to it's breaker sizing only because it gives the do it your selfers's down the road more of an ease to overload the panel with a bunch of circuits. As far as legality though, as long as load count is okay, which it's not most of the time, it's okay....I think.


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## TOOL_5150 (Aug 27, 2007)

I have a 100 amp main breaker feeding a 225 42 space panel in my own house. When all the wiring is done, I will have used most of the 42 spots.

~Matt


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## leland (Dec 28, 2007)

Ya,and checking the prices- The MB panels are less $ than the MLO.:thumbsup:
(SqD QO)


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## redbeard43 (Mar 20, 2009)

where have you checked Leland? MB are cheaper? No way, I can get MLO wayyyy less than a MB. Your set up is fine and if you get them cheaper, go for it. What if you took the main out and used a smaller breaker (100) to feed the panel, then you would have a spare 200?? ;-)


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## redbeard43 (Mar 20, 2009)

oh crap , i forgot...I have done what you said, 42 ck with 200mb and set a 125a mlo 24 ck to the side and feed it with a 100a. ive installed the AFCI in the sub for the bedrooms and maybe smaller general use circuits, this way i can leave spares in both panels for future use.


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## Archania (Mar 16, 2009)

If you want to "feel" better, I don't think you even have to have that main switch in the sub panel?? You should be able to run it without it, depending on the panel... But yea, it doesn't matter, but in a way it is kind of nice to have a disconnect right there instead of having to go back to the main panel to shut the power off to the sub.


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