# NEC 2008 Service Panel Question



## SPRKY (Mar 1, 2009)

Using full size breakers, what is the least number of spaces allowed in a service panel. According to 2008 NEC. AND what is the code ref.


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## 480sparky (Sep 20, 2007)

What do you mean by 'spaces'? How many circuits? How many breakers must be installed? How many spares must be left after loading the panel?


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## MDShunk (Jan 7, 2007)

I don't think a service panel needs any spaces. Your service can stop at a service rated disconnect, for instance. Everything after that, like a subpanel with all the "spaces", would be load side equipment. 

I say ONE.... since you are allowed 20 and 30 amp 120V services for things like billboards and school crossing signs. One is all you'd need for the disconnect.


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## SPRKY (Mar 1, 2009)

This is a res. single-family 120/240 volt, 1 phase, 3-wire dwelling.

The question is "Using full size breakers, a panel with spaces for___ breakers is the smallest that can be used for a service panel" I need the 2008 NEC code ref. that specifies the least number of spaces available in a service panel.


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## 480sparky (Sep 20, 2007)

SPRKY said:


> This is a res. single-family 120/240 volt, 1 phase, 3-wire dwelling.
> 
> The question is "Using full size breakers, a panel with spaces for___ breakers is the smallest that can be used for a service panel" I need the 2008 NEC code ref. that specifies the least number of spaces available in a service panel.


 
Then I'd say four. 210.11(C)(1), (2), and (3).


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## william1978 (Sep 21, 2008)

What is the point of your question? Why are wanting to buy the smallest panel? I would want atleast some empty spaces left for future cirs to be added.


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## MDShunk (Jan 7, 2007)

Since "service panel" has no definition in the code, I say the whole question is invalid. 

I still say you don't need any spaces. Your spaces can all be in a subpanel.


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## SPRKY (Mar 1, 2009)

Well to answer William1978's question, it is a question on an exam same as "What is the maximum spaces" and the answer to it is 42 found in code ref. 408.15.

Thank you 480sparky although it's not quite the answer I am looking for.

I like MDShunk's answer also. It may be a trick question.

Thanks guys,
signing off.

Thks,
SPRKY


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## 480sparky (Sep 20, 2007)

SPRKY said:


> Well to answer William1978's question, it is a question on an exam same as "What is the maximum spaces" and the answer to it is 42 found in code ref. 408.15.........


408.15 has been deleted in the 2008. There is no maximum any more.

I'm not sure what you're asking for now. If four isn't the answer (2 SABC, 1 kitchen, 1 bath) then I guess the answer would be zero.


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## SPRKY (Mar 1, 2009)

My mistake. We will see what the teacher has to say. I will let you know later.


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## SPRKY (Mar 1, 2009)

I got on the Mike Holt forum: 

_You can have a service that consists of a single 15 amp circuit. So my answer would be "one." Reference 230.79(A). I can't think of any other way to answer this question. I strongly suspect that its author has an incorrect understanding of the code._

Thank you guys


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## BEAMEUP (Sep 19, 2008)

Here is my take on the question, Since the "service panel" is installed, you would need one circuit. For a light & a gfi. You need to have these by code. We do this set up all the time for strip malls that have no tenants.


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## SPRKY (Mar 1, 2009)

Thanks Beameup.

Here is a new question.

My daughter has an older house. It has 10 amp breakers. She has a dimmer (Older style) switch in her kitchen. The top and bottom screws (that hold the cover on) gets hot to the touch after the switch is been on for a while. The switches are 15 amp switches.

What do you think.


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## BEAMEUP (Sep 19, 2008)

I would check and see how much wattage is on the dimmer. If the dimmer is a standard 600 watt dimmer, and any of the heat sink fins are broken off, you need to derate the dimmer. After this step count how much wattage is on the dimmer. 

*Dimmer *600 W 
*No sides removed *600 W max.
*1 side removed *500 W max
*2 sides removed *400 W max.​ 
*Dimmer *1000 W 
*No sides removed 10*00 W max.
*1 side removed *800 W max
*2 sides removed 65*0 W max.​ 
This will cause the screws to get warm or even hot. They shouldn't be hot enough that you would have to remove your finger from the screws.


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## ralpha494 (Oct 29, 2008)

I'll betcha that you're reading the larger 10 and not the smaller comma and 000 on an older Square D breaker. (the 10,000 AIC) The amperage is raised on the very end of the handle, probably a 15, maybe a 20. 

Older dimmers used a resister/heat sink to dissipate the heat, sometimes the metal front of the dimmer switch, so I'll guess that the metal 6-32 screws are screwed into that, and will heat up. If they get hot enough to burn you when you touch them they might get hot enough to do worse. You would have noticed the plastic switch cover melting or discoloring. You might want to check into newer electronic dimmers.


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## william1978 (Sep 21, 2008)

SPRKY said:


> My daughter has an older house. It has 10 amp breakers.


 Do you have a picture of the breaker, because I've never seen a 10a breaker.


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## drsparky (Nov 13, 2008)

10 amps are available from Square D, I'm sure everyone else offers them to.


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## SPRKY (Mar 1, 2009)

Thanks again Guys,

I will post a photo tomorrow.


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## william1978 (Sep 21, 2008)

SPRKY said:


> Thanks again Guys,
> 
> I will post a photo tomorrow.


 That would be cool. I googled it and found a few pictures of some 10a breakers,but I still would like to see your picture.:thumbsup:


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## prldrp1 (Jun 1, 2009)

the question states for *reidential use* so...2 cir. for kitchen...1 for lighting...1 for general power....1 for bathroom....1 for arc/fault bedrooms...1 for furnace....1 for laundry....if equiped 1 for sump pump...so I come up with 8...possibly 9 circuits min.


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## MDShunk (Jan 7, 2007)

prldrp1 said:


> the question states for *reidential use* so...2 cir. for kitchen...1 for lighting...1 for general power....1 for bathroom....1 for arc/fault bedrooms...1 for furnace....1 for laundry....if equiped 1 for sump pump...so I come up with 8...possibly 9 circuits min.


WRONG! The "service panel" could be little more than an outdoor disconnect. All those circuits you talk about could be in an indoor subpanel.


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## prldrp1 (Jun 1, 2009)

MDShunk said:


> WRONG! The "service panel" could be little more than an outdoor disconnect. All those circuits you talk about could be in an indoor subpanel.


 
that is true if there is a private power pole on the property, but in my area...the first point of diconnect besides the meter itself is in the home...that is the service panel where all the branch circuits begin, only exception to this would be if your panel was mounted more than 5 feet away from the point the conductors enter the building, than a disconnecting means is required outside on the wall. In the Chicagoland area almost all metering is mounted on or in the building itself.....very rarely is there a private power pole


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## 480sparky (Sep 20, 2007)

prldrp1 said:


> that is true if there is a private power pole on the property, but in my area...the first point of diconnect besides the meter itself is in the home...that is the service panel where all the branch circuits begin, only exception to this would be if your panel was mounted more than 5 feet away from the point the conductors enter the building, than a disconnecting means is required outside on the wall. In the Chicagoland area almost all metering is mounted on or in the building itself.....very rarely is there a private power pole


 
I'd like to see a meter socket that's rated as a disconnect.


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