# Double panel question



## JohnJ65 (May 8, 2008)

I'm revisiting an old topic that I asked about some time ago instead of digging up an old thread. 

https://www.electriciantalk.com/f9/double-panel-design-question-214186/

So I'm putting together an estimate for a residence were they have an old panel which is chock full of tandems and a complete mess, with about 30 circuits in the panel and three small breaker enclosures next to it with breakers for the dryer and two A/C units (taped off the main lugs). Installing a 40 space panel will leave them with very little future growth or more tandems soon. 

I want to install two 30 space panels in place of this mess and ideally would like to feed both with 200 amps. I would be using a main breaker panel and feeding the panel next to it with a sub-feed kit (Siemens) which takes up four spaces in the first panel, then from there feed the main lugs in the second panel. 

I've done double panels in residences with a 200 amp main breaker then a 100 amp sub next to it fed with a 100 amp breaker. I could easily do this one the same but I would rather have the 200 amp capacity on both. 

My question are:
#1 If I feed with a sub feed kit do I need to run the water main ground to both panels bonding the neutral in both? 

#2 Is this considered one panel with two sections. circuits 1-30 in first 31-60 in second section?

Please bear with me on this I want to make sure it's right so the inspector uses the green sticker instead of the red one. I'm seeing more and more places where I would like to do double panels these days with the AFCI/GFCI requirements.

Thank you for any insight on this. 
John.


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## cdslotz (Jun 10, 2008)

#1 - No. A sub panel is still a sub panel

#2 - Two-section panel has feed thru lugs. Section #2 would have to be same amperage as section #1


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## cdslotz (Jun 10, 2008)

I may be wrong on this after reading again. I'm not familiar with a "sub-feed kit"

I'll wait for other responses....


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## HackWork (Oct 2, 2009)

cdslotz said:


> I may be wrong on this after reading again. I'm not familiar with a "sub-feed kit"
> 
> I'll wait for other responses....


Yeah, I don't know how this works. You can see an example of the sub-feed kit in the other thread. I am not sure if that counts the same as feed-thru lugs or not.


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## WPNortheast (Jun 4, 2017)

What about a 200a 40 ckt with 125a feeding a 30ckt sub? Keep all big stuff in 200 amp Think hard maybe do calculations feeding the other box more than 125 is $$.
Or
I was in a similar situation, but with 2 boxes out of the question. My Siemens and my GE dealer had nothing above 40 space. QO wasnt in the budget. Found this and it was perfect.
https://www.homedepot.com/p/GE-200-Amp-40-Space-80-Circuit-Main-Breaker-Indoor-Load-Center-Contractor-Kit-TM4020C80K/301157960


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## JohnJ65 (May 8, 2008)

Here is the link to the sub feed kit. They make them in 125 amp and 150/200 amp. I bought one awhile ago and it bites onto the buss very tightly, I was skeptical about it at first. 

https://www.homedepot.com/p/Siemens-Sub-Feed-Lugs-for-150A-225A-Load-Centers-ECLK2225/207050664

The dead front sets overtop of it, so the twist outs should remain in those four spaces.


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## JohnJ65 (May 8, 2008)

I have done a double panel setup with the 200 amp main and a 100 amp sub next to it, of course the inspector asked why I just didn't feed them both with 200! 

I should have seized that opportunity to ask his opinion on how to do that.


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## CoolWill (Jan 5, 2019)

Find a panel with feed-thru lugs. Or get one of those 60 circuit panels.


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## Going_Commando (Oct 1, 2011)

JohnJ65 said:


> I have done a double panel setup with the 200 amp main and a 100 amp sub next to it, of course the inspector asked why I just didn't feed them both with 200!
> 
> I should have seized that opportunity to ask his opinion on how to do that.


That's because the inspector is an idiot. You arent gaining anything by feeding the sub with 200A over 100A. If a house needs only a 200A service but has enough circuits to require more than 40 spaces than most of the circuits won't have any load on them worth mentioning.


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## HackWork (Oct 2, 2009)

Going_Commando said:


> That's because the inspector is an idiot. You arent gaining anything by feeding the sub with 200A over 100A. If a house needs only a 200A service but has enough circuits to require more than 40 spaces than most of the circuits won't have any load on them worth mentioning.


I agree with this. Install a 200A main and a 100A sub.

Put all of your big loads in the main. Leave a few spaces in the main for future large loads like a hot tub or vehicle charger. Then use the 100A sub just for future general circuits.

I will typically use a 90A breaker and #2 AL for the subpanel, then change out the breaker to 100A after the inspection.


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## macmikeman (Jan 23, 2007)

Going_Commando said:


> That's because the inspector is an idiot. You arent gaining anything by feeding the sub with 200A over 100A. If a house needs only a 200A service but has enough circuits to require more than 40 spaces than most of the circuits won't have any load on them worth mentioning.



This ^^^^^^^^^^^^


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## JohnJ65 (May 8, 2008)

Your right, I'm over engineering this. That panel probably only has 40 amps on it at any given time when they are home at dinner time in the summer.

The biggest problem I have with these houses with so many home runs added over the years is the fact that I'm running out of space in the top of the panels. This is not as big of a problem in a basement but when the panel is in a wall between two studs it's a challenge. 

John.


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## HackWork (Oct 2, 2009)

JohnJ65 said:


> Your right, I'm over engineering this. That panel probably only has 40 amps on it at any given time when they are home at dinner time in the summer.
> 
> The biggest problem I have with these houses with so many home runs added over the years is the fact that I'm running out of space in the top of the panels. This is not as big of a problem in a basement but when the panel is in a wall between two studs it's a challenge.
> 
> John.


Yup, that is an issue. That's why I don't care for these new panels that have more than 42 circuits in them, just too many wires. I don't like putting more than 30 circuits in a residential 14.5" wide panel.


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## wcord (Jan 23, 2011)

JohnJ65 said:


> Your right, I'm over engineering this. That panel probably only has 40 amps on it at any given time when they are home at dinner time in the summer.
> 
> The biggest problem I have with these houses with so many home runs added over the years is the fact that I'm running out of space in the top of the panels. This is not as big of a problem in a basement but when the panel is in a wall between two studs it's a challenge.
> 
> John.


60 and 84 cct panels are common up here. 
That being the case, I usually spend the extra few minutes and slot out the side studs to allow access to the knock outs. I'll use the side knockouts first and then the end ones. Don't forget to use nail plates on the studs


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## Galt (Sep 11, 2013)

I think I mentioned it before is it time to make the panels 4 inches wider and be done with it.


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## JohnJ65 (May 8, 2008)

I think two panels are going to be better then one these days, 28" of knockouts instead of 14". 

If you have a picture of how you slot out the studs to use the side knockouts I would love to see that. 

John.


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## wcord (Jan 23, 2011)

JohnJ65 said:


> I think two panels are going to be better then one these days, 28" of knockouts instead of 14".
> 
> If you have a picture of how you slot out the studs to use the side knockouts I would love to see that.
> 
> John.


Sorry, don't have one.
I drill a couple of 7/8 holes beside each other, top and bottom of what ever length i need to cut and slice out a piece of wood about 1.5 to 2 inches wide. 
Its usually big enough to get to 1 row of KOs .
Leaves about .75 to 1 inch of wood front and back of the stud.
You have to leave enough wood on the top and bottom to be able to screw the panel to the studs.
Of course you can't do this if its a bearing wall
Either that or become a Canadian and turn the panel sideways:wink:


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## mikewillnot (Apr 2, 2013)

Square D qo has 54-space and 60-space models


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