Need Advice - 2 x 200 Amp Panels Possible?

[RyanEricW]

Hello

Recently my father purchased a house and had it inspected and there were some things missed that are rather alarming regarding the main panels inside the home

Originally the home was a duplex, with 2 meters, 2 power boxes and was converted into a single family home. Now it has 1 set of feed wires going to 1 box, and that box has a 60A breaker feeding the other 100AMP panel on the other side of the wall. This is definitely not correct!

He was wanting to add a circuit breaker for some really high power sound system equipment, and add a bathroom in the basement, but when I added up his total circuit breaker amperage it's wayyyyyyyy over the limit

I'll call these Basement 1 and Basement 2

Basement 1 - 100A Panel - 395A worth of circuit breakers - Main Feed IN
Basement 2 - 100A Panel - 325A worth of circuit breakers - Powered by 60A Breaker on Basement 1 Panel

IIRC, you are only supposed to have AT MAX double the capacity of the main breaker, so we are looking for solutions here.

My idea was add 2 x 200 Amp Panels next to each other, but I have never done a double panel setup, only swapped out single panels.

I'm assuming now:

- The wiring from the pole to the meter needs to be rated for 400A
- The meter needs to be able to handle 400A
- Meter base needs a double lug?
- There needs to be 2 complete sets of wires from the meter base. Each set running from the meter to each panel respectively

Am I right here, or would you change anything?

Keep in mind this is a big house now, it has 6 bedrooms, 2 bathrooms, huge kitchen, a detached 2 car garage, full finished basement, radon system, sump system, etc and needs a lot of breakers to handle modern power requirements but I think I can combine quite a few breakers and drop down many of the 20A breakers to 15s to save some "capacity"

Currently he isn't having too many issues except when he plugs a circular saw or something into the kitchen. It's amazing they aren't popping more breakers (if they even work still, panels are old)

 

[sberry]

Keep in mind this is a big house now, it has 6 bedrooms, 2 bathrooms, huge kitchen, a detached 2 car garage, full finished basement, radon system, sump system, etc and needs a lot of breakers to handle modern power requirements but I think I can combine quite a few breakers and drop down many of the 20A breakers to 15s to save some "capacity"

It wont save anything. You can have hundreds of breakers in the panel, I have near a thousand in a 200, right now drawing about 10A. 5 from 1 200, along with its own and another 75 breakers on the subs, maybe more.
The fact that it hasn't tripped a 60 feeding a panel says a lot about its real load, thousands of 100A panels are fed from 60. I have 9 on one service alone.

 

[sberry]

This doesn't mean it doesn't need to be replaced but,,, its obviously not tripping a 100A breaker. A general circuit can have several outlets, possibly hundreds of amps of connected equipment. If it pulls more than 20 the breaker trips, if 1 thing at a time is used its irrelevant how much is connected.
Changing breakers from 20 to 15 does not add capacity, only thing that does is removing actual load.

 

[sld961]

It wont save anything. You can have hundreds of breakers in the panel, I have near a thousand in a 200, right now drawing about 10A. 5 from 1 200, along with its own and another 75 breakers on the subs, maybe more.
The fact that it hasn't tripped a 60 feeding a panel says a lot about its real load, thousands of 100A panels are fed from 60. I have 9 on one service alone.

I have the same thoughts as sberry. I wouldn't worry about it.

Is there a code that says 2x?

Sent from my SM-G960U using Tapatalk

 

[nh_yota]

Breaker size doesn't matter it's the calculated load that matters, and the size of the main breaker on the secondary panel doesn't matter because it's protected by the 60A breaker in the main panel.

Sounds like it's fine.

 

[sberry]

Is he going to fill 6 bedrooms full in near future, have people working in the garage while having parties in the basement?
I have an electric heater I cant see from here, about 10A and my fridge just came on and making a pot of coffee. So I added a little load in the last few minutes for a short time and if one added up all the breakers from subs and itself would have a couple thousand amps with 20 being used now and most will quit in next few minutes.

 

[RyanEricW]

This isn't fine, the main panel is overloaded. Actual load is irrelevant because right now it's possible to overload the buss bars and possibly start a fire.

Right now the house isn't being fully utilized, so sure there aren't any issues, but as more stuff is added, this is going to become an issue.

I guess I should rephrase, I'm not looking for someone to tell me if the 2 x 100 amp panels in their current configure is fine. I'm looking to see if someone can give advice swapping to 2 x 200 amp panels

 

[nh_yota]

This isn't fine, the main panel is overloaded. Actual load is irrelevant because right now it's possible to overload the buss bars and possibly start a fire.

How do you know the main panel is overloaded? Did you hook up an amp clamp?

 

[sld961]

This isn't fine, the main panel is overloaded. Actual load is irrelevant because right now it's possible to overload the buss bars and possibly start a fire.

How? Once you get 100 amp load from the main box, main breaker trips.

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[nh_yota]

I don't think you understand the point we are trying to make. The 100A panel in my house has probably 500A worth of breakers in it and that's fine because the calculated load of everything in the house is less than 100A.

 

[sberry]

This isn't fine, the main panel is overloaded. Actual load is irrelevant because right now it's possible to overload the buss bars and possibly start a fire.

Right now the house isn't being fully utilized, so sure there aren't any issues, but as more stuff is added, this is going to become an issue.

I guess I should rephrase, I'm not looking for someone to tell me if the 2 x 100 amp panels in their current configure is fine. I'm looking to see if someone can give advice swapping to 2 x 200 amp panels

We realize what your intent is but we also want you to learn something along the way that helps with load sizing and capacity needs. If I could do the job with a single 200 I would be inclined to do it. If I was going to add hot tubs, new air conditioning, electric heat or water heaters then it effects all this.

The main isn't tripping, yes it could and its almost always possible to do it but it wont overload the buss,,, hence the main, it prevents this.
The actual load is the only thing that is relevant. An alarm clock or table lamp plugs in to a 20A circuit, you do not count the load as 20A because that's what the breaker is.
Lots of dedicated equipment like this, sump pump, 1/3 hp, air cond, lots of them on 30A circuits with a draw of 13.

 

[RyanEricW]

The buss bars are theoretically overloaded by the total CB amperage

On the panels - "Maximum rating sum of all breakers 140 per a stab"
That's 280 max amps

Basement 1 is setup to allow 395A it's a safety hazard, not to mention I have zero room to add on

 

[sberry]

I will agree that you might want to do an upgrade and maybe you need to but these guys are trying to help with some faulty rationale. Your thinking about this is not dangerous but its not really correct either. Its based on some faulty assumption and this is part of the fundamentals of electric service 101. Lots of basic service design and over current protection based on applied and calculated load. This becomes important when adding future equipment.

 

[sberry]

The buss bars are theoretically overloaded by the total CB amperage

On the panels - "Maximum rating sum of all breakers 140 per a stab"
That's 280 max amps

Basement 1 is setup to allow 395A it's a safety hazard, not to mention I have zero room to add on

Again,,, you do not understand some of this, you are trying to argue with people that do. This is per stab,,, not per buss.
I will not argue that you do not need room or capacity but its not a straight line, different thing but relevant to system design.

 

[Norcal]

The buss bars are theoretically overloaded by the total CB amperage

On the panels - "Maximum rating sum of all breakers 140 per a stab"
That's 280 max amps

That does not mean what you think it is. That means if a 100A breaker was plugged in on one side the maximum size breaker opposite it would be 40A. And that applies only to that bus stab, what is really important is the calculated load the sum of the breaker rating is irrelevant.

 

[RyanEricW]

I get that and appreciate that, I'm always down to learn new things probably like the rest of us.

All I have to go by is the panel manufacturer recommendations. If they made a 100A panel, protected by a 100A circuit breaker, and it says 280 max amps, 140 per stab and it's currently sitting at 395A, I don't think I should have to try and convince people that this isn't correct

I get that realistically it's fine, because it hasn't tripped the 100A breaker, but as they start adding high load items in the house, this is definitely going to be a nightmare and seeing as the bars have the potential to be overloaded it's a safety risk. It's current setup is completely against manufacturer specifications for how they built the panels

A 200 Amp panel will typically have 200A per stab, which if I added 2 would correct this situation inside the manufacturer parameters for both panels, but would leave little room for expansion, which is why I'm going to knock down many of the breakers or combine some for added "capacity"

 

[nh_yota]

If you go to an electrician and say "I need you to upgrade my service to 400A and install two 200A panels" they likely say "okay" and take your money.

If you go to an electrician and say "I think my panels are overloaded and I need space for new circuits, can you look at it and provide a recommendation" they will likely say "okay" and save you some money.

 

[RyanEricW]

That does not mean what you think it is. That means if a 100A breaker was plugged in on one side the maximum size breaker opposite it would be 40A. And that applies only to that bus stab, what is really important is the calculated load the sum of the breaker rating is irrelevant.

Well then maybe the electrician I learned all of this from was completely wrong. Time to do more research then

 

[sberry]

The buss bars are theoretically overloaded by the total CB amperage

The hopper on a semi trailer is large enough that it can legally overloaded with steel, it can be done but someone has determined the legal applied load. Not sure that is a good example but maybe someone can come up with better analogy.
There is probably a forum that will explain a 2x200 setup but one worth a pinch of **** wont do it until there is some basic understanding of a couple fundamental principles first. This is one. There are a couple others that wont make sense when you get to them, some depends on the local utility, it will seem strange when you find out its legal to connect 2x200 to a 325 base.

 

[mm08822]

This isn't fine, the main panel is overloaded. Actual load is irrelevant because right now it's possible to overload the buss bars and possibly start a fire.

Right now the house isn't being fully utilized, so sure there aren't any issues, but as more stuff is added, this is going to become an issue.

I guess I should rephrase, I'm not looking for someone to tell me if the 2 x 100 amp panels in their current configure is fine. I'm looking to see if someone can give advice swapping to 2 x 200 amp panels

The buss bars are theoretically overloaded by the total CB amperage

On the panels - "Maximum rating sum of all breakers 140 per a stab"
That's 280 max amps What do you mean???

Basement 1 is setup to allow 395A it's a safety hazard, not to mention I have zero room to add on

The panel buss bars will not be overloaded because the main circuit breaker will prevent that from happening. The sum of all breakers installed has NOTHING to do with the actual load placed on the service.

As for the buss stab rating, it relates to the total amperage draw from two cb's horizontally adjacent to each other that are each attached to the same stab. Unless you have two loads simultaneously drawing >140A, it is nothing to worry about.

If it makes you feel better, make sure each maximum rating sum is LEQ 140A for each horizontal pair.

 

[Innovate1]

I agree with the other posters. The 100A main breaker protects the main panel. The 60A breaker limits the current to the other panel (now configured as a sub panel). The 100A main in the subpanel will never trip because of it's higher rating but can be used as a disconnect for the panel. If the panel was at another location a single shut off may be required.

I currently have a house with two 200A panels. This is apparently common in this area. The power company supplied a 325A meter base with dual lugs. Even though this isn't 400A it is allowed because it is unlikely both panels will be at full load that the same time (I am just repeating how the power company explained it to me, not saying this is the best way). For me it wasn't a matter of capacity but seemed like the best way to have room for all the breakers I needed.

The fact that you have nearly 400A of breakers in a 100A panel doesn't allow you to overload it. The 100A breaker will trip to protect the panel - that's what it is there for.

If you are getting trips of the 100A breaker (which you didn't mention) then you may want to install a bigger panel. Putting in a single 200A panel and increasing the breaker to the second one to 90 or 100A (and the interconnecting wires!) would nearly double your capacity.

The 60A breaker feeding the 100A panel isn't wrong - it's done regularly. There could be other things wrong with your electrical but from what you have posted I don't see any issue. Believe me, if there was something wrong people here would let you know.

The saw tripping a breaker sounds like an individual circuit issue and not a problem with overall capacity.

If you are convinced you want two 200A panels you can certainly do that. Same as when someone posts they want to do something that isn't to code they can do that. Usually people here like to spend others money on bigger stuff. But it isn't clear that it is really needed in this case. I suggest you contact a local electrician about this. How dual panels are handled can vary with location.

 

[sberry]

I get that realistically it's fine, because it hasn't tripped the 100A breaker, but as they start adding high load items in the house, this is definitely going to be a nightmare and seeing as the bars have the potential to be overloaded it's a safety risk. It's current setup is completely against manufacturer specifications for how they built the panels

A 200 Amp panel will typically have 200A per stab,

Its still 140 a stab, irrelevant if its 100 or 200.

Well then maybe the electrician I learned all of this from was completely wrong.

There is a difference between hearing and learning. You are doing "research here" and reading everything everywhere isn't going to help much. You need to digest this a little bit.

I don't think I should have to try and convince people that this isn't correct

You think you understand this, you don't need to convince anyone and are not going to, especially Alfred, Norcal and a couple others here been masters for decades. Some of them did this hundreds of times.

 

[nh_yota]

The difference between the panels and the meter is that the panels are rated at 80% load and the meter is rated at full load, which is why a 400A residential service has a 320A meter base.

400 x 0.80 = 320
320 x 1.25 = 400

 

[sberry]

You could go down one side of a 20 space panel with 10 100A breakers and down the other with 40. 1400A of breakers in a 100A panel and be legal. This is kind of a theoretical but legal.

 

[mm08822]

How many branch circuits is each panel rated for?
How many branch circuits are installed in each?

 

[Innovate1]

It always amazes me when people ask for advice and then object when they don't get the answer they wanted.

We aren't trying to be difficult, actually you are getting good advice. But you have some fundamental misunderstandings of how this works and what is needed to be safe and code compliant.

 

[RyanEricW]

It always amazes me when people ask for advice and then object when they don't get the answer they wanted.

We aren't trying to be difficult, actually you are getting good advice. But you have some fundamental misunderstandings of how this works and what is needed to be safe and code compliant.

Your comment is completely unnecessary

 

[sberry]

Many of the other threads I babble on about are the same thing, the brand of wrench doesn't change how tight the bolt is and the size of the comp doesn't change the demand for a tool. A bigger comp may let it run longer but a 1/2 air gun uses the same,,, basically no matter what the comp is.
There is an air line size thread right now about this, lets say 1/2 is sufficient but I am going to use a 3/4 in case I get a bigger comp. Ok,,,, are you going to use the same tool?
Its the applied load that determines demand not the size of the comp and in some cases a better comp may actually improve the function of the air line. Cheaper single stage comp may need a bigger line where a 2 stage will deliver more air on same size or smaller line.
If the goal is to later get a larger impact then it makes sense to provide a larger line.

 

[RyanEricW]

Stab clarification -

Most Square D QO or HOMELINE panels are supplied with "double row" bus
bar construction. This means that the bus bars will have branch circuit
breakers plugged onto the bus bars from the left and from the right.
The "bus stab", "bus finger" or even "connector finger" is the point on
the bus bar that the branch circuit breakers electrically connect to the
bus bar. For instance, a 40 space panel will have 20 "bus stabs". The
bus stabs accept circuit breakers from both sides, providing the
capability to plug on 40 1-pole circuit breakers.

If your panel is restricted to 125 ampere per bus stab, that means that
you cannot put two breakers onto that bus stab (one from each side)
that exceed 125 amperes between them. For instance, you could place two
60 ampere breakers (60A+60A=120A) across from one another on the same
bus stab(s), but you could not place two 70 ampere breakers
(70A+70A=140A) across from one another on the same bus stab(s).

This restriction is not applied to all QO or HOMELINE panels. The
restrictions are applied only when we must limit the total amperage on a
stab to pass applicable UL heat rise tests.

- Square D Company

 

[Innovate1]

Consider this... Since you have over 700A of total breakers how do you figure two 200A panels will be sufficient? Each of the 200A panels will still have WAY over 200A total breakers in it. By your way of thinking this would still be a hazard. It isn't though. I think if you look at almost any home breaker panel the total of the breakers will be significantly over the main breaker rating.

 

[sberry]

So,,,, what does that mean to you?

 

[RyanEricW]

Consider this... Since you have over 700A of total breakers how do you figure two 200A panels will be sufficient? Each of the 200A panels will still have WAY over 200A total breakers in it. By your way of thinking this would still be a hazard. It isn't though. I think if you look at almost any home breaker panel the total of the breakers will be significantly over the main breaker rating.

I was taught that the panel should never exceed double the breaker rating for reference. Meaning a 100 AMP panel should never exceed 200A worth of breakers.

A single 200A panel would mean I could put 400A worth of breakers in safely

Using 2 x 200A panels would mean I could put 800A worth of breakers in safely.

I would be below well 800 total breaker amps with two panels and combining a few low power circuits. Probably around 600-700

If you really wanted to know

 

[mm08822]

The buss is different than a stab.
For a simplistic explanation, there is a left buss and a right buss.
The left buss is offset from the right buss one position vertically.
Each buss has a rated maximum current it is designed to carry protected by the main cb.

Each buss includes stabs that typically enable 2 cb's to be connected to it in a horizontal direction.
Each stab has maximum load that it can handle. Typically less than the buss rating. In your case 140A.

If you really want to learn some thing, buy a clamp-on meter and measure the sub-panel load and the overall house load at different times. I am certain you will find those numbers very low.

Available branch circuit breaker space is another story.

It is an urban myth that 2x worth of branch cb's is the limit in a panel.

***************

So you made post 29 while was typing. Since that info is straight from the mfr, do you now realize you came here with only half of the understanding?

 

[nh_yota]

I was taught that the panel should never exceed double the breaker rating for reference. Meaning a 100 AMP panel should never exceed 200A worth of breakers.

That may have been a rule of thumb some electrician used when installing a new panel so they didn't need to do a load calculation, but it's not a fact.

 

[Innovate1]

I wasn't aware of the bus stab limit. I don't do much of this stuff so will try to remember that. Thanks.

 

[RyanEricW]

So,,,, what does that mean to you?

From what I gather it means these 2 x 40s is acceptable on a 200A stab rating shown in this picture.

But if each breaker was "100" on each side I would literally be at the limit for that stab or metal protrusion inside the box

 

[sberry]

I was taught

This is somewhat the same as I was always told and someone told me. This is somewhat what compelled me to study code. People that were telling didn't know, if they did they didn't make it clear that I understood what they meant.
There is NO rule that says that the accumulated breakers must be limited to this. Its something you were told and now assume its gospel which it isn't and not even relevant unless it is very specifically part of a calculated load,,, the kind that really doesn't apply here at this point.

 

[sberry]

From what I gather it means these 2 x 40s is acceptable on a 200A stab rating shown in this picture.

But if each breaker was "100" on each side I would literally be at the limit for that stab or metal protrusion inside the box

Not exactly. If it had a 200 rating it would allow 100 across from each other. If it was 125 would allow 100 and a 20 on the other side, if it was 140 would allow 100 and up to 40.
The 2x40 is acceptable. 2x40 is putting 80 on a stab.

 

[mm08822]

From what I gather it means these 2 x 40s is acceptable on a 200A stab rating shown in this picture.

But if each breaker was "100" on each side I would literally be at the limit for that stab or metal protrusion inside the box

Where did you get 200A rating for the stab?

Post a clear pic of the panel label that shows all of the accessory part #'s/spec for the panel.

 

[nh_yota]

Another myth-being-regarded-as-fact is the max number of receptacles allowed on a branch circuit. Some people say 12 and other say 8 or 10. Under the NEC there is no limit to the number of outlets per circuit in a dwelling, however state or local codes may impose a limit such as 12 based on assumed load per receptacle.