AFCIs filling up the panel

Status
Not open for further replies.

Ken Olson

Member
Location
Rocky Point, NY
Looking at a new 2400 sq ft home in 2012 . . . a 30/40 panel has been rendered to 30 circuits because of the plethora of AFCIs. If all 30 spaces are used, I could quad the A/C and Range to pick up 2 spaces. But the real question is . . . Are twin/tandem breakers still allowed in new construction?
 

templdl

Senior Member
Location
Wisconsin
If it is a 30ckt panel then you can't install more than 30. The panel must be rated for it. If the panel is rated for twin breakers, unless the specs tell you otherwise there is no problem using a panel that s "listed" for use with tandem breakers.

It appears to be as though somebody didn't consider the problem that you are having which is certainly not a fault of yours.
You have been provided a 30ckt panel and are require by the code to install a given number of AFCIs is it along with the 240v loads which could be a range, A/c, water heater, and clothes drier that's up to 8 pole spaces. Then, AFCIs take up 1 pole space apiece. It apears as though you panel is only rated for 30ckts with 30 pole spaces.
You may be dead meat on this one. Sub panel time?? Show the issue to the contractor where he would need to add time and materials to the change that may be required.
It may be that they are trying to put 10# of ____ in a 1# bag.
 
Last edited:

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
It's a 30/40 panel , what's wrong with installing tandems as long as they are rated for the use.
 

Gac66610

Senior Member
Location
Kansas
IMO as long as its rated for tandems, you can use them
I use a 32/40 and use "thin"(GE) breakers quite often
lot less expensive than use a full 40/40 panel
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
I have not had to wire a house to 2011 code yet, but had issues with 42 circuit three phase panel boards overheating with very little load, the arc faults put off a fair amount of heat, and when you have 42 of them, it warms things up quite a bit. (assisted living center) The manufacture paid us to replace all of them with an upgraded breaker, but I wonder if any other manufactures have the same issue?
 

Gac66610

Senior Member
Location
Kansas
I have in the past, but it was when we would stack the breakers it was suggested that we stagger the AFCI with regular breakers ... PITA
(wouldn't help with all breakers in panel being AFCI)
they have come out with another "mod 3" AFCI does not seem to cause problems due to heat
still have trouble with them tripping where HO's have plasma screen TVs however ... another PITA
 

kwired

Electron manager
Location
NE Nebraska
I have not had to wire a house to 2011 code yet, but had issues with 42 circuit three phase panel boards overheating with very little load, the arc faults put off a fair amount of heat, and when you have 42 of them, it warms things up quite a bit. (assisted living center) The manufacture paid us to replace all of them with an upgraded breaker, but I wonder if any other manufactures have the same issue?

Difference between a typical dwelling and your assisted living center is that there likely is not as much continuous loads in the typical dwelling - even if not heavy loads, they are creating some heat within the thermal trip mechanisims of their associated breaker continuously.


Also remember we no longer have a limit of 42 poles in the panel - so you could have even more heat in a 60 or 84 circuit panel.
 

hillbilly1

Senior Member
Location
North Georgia mountains
Occupation
Owner/electrical contractor
Difference between a typical dwelling and your assisted living center is that there likely is not as much continuous loads in the typical dwelling - even if not heavy loads, they are creating some heat within the thermal trip mechanisims of their associated breaker continuously.


Also remember we no longer have a limit of 42 poles in the panel - so you could have even more heat in a 60 or 84 circuit panel.

The load on all of these breakers was less than 1 1/2 amps, way to much heat given off for such a small load.
 

templdl

Senior Member
Location
Wisconsin
The heating comes from the electronics.
There should be no restriction as to how they are placed in the panel with regard to heating unless instructions dictate otherwise.
The warmth of each breaker by itself is small but can add up when there are a number of AFCIs involved. But, more often than not when we expect an object to be cool to the touch when that object is worm it is common to consider to be hot. Hot is when you can't hold your hand on it very long.
I is good to be prudent with installations but again it is also important to comply with the manufacturers instruction. If the manufacturer has not instructed to co otherwise install these breakers as one customarily install them.
 

rt66electric

Senior Member
Location
Oklahoma
cost comparison 30 vs 40

cost comparison 30 vs 40

The last time I added it up. The cost of a 30ckt panel with 3 tandem twin breakers was more than the cost of a 40ckt panel with normal 1P breakers.

The cost diffference between the two, was not worth the cost of -the skin off my knuckles-(and headache) required to cram 32 circuit in a 30 ckt panel.
 

electricmanscott

Senior Member
Location
Boston, MA
The last time I added it up. The cost of a 30ckt panel with 3 tandem twin breakers was more than the cost of a 40ckt panel with normal 1P breakers.

The cost diffference between the two, was not worth the cost of -the skin off my knuckles-(and headache) required to cram 32 circuit in a 30 ckt panel.

Exactly. I see this all the time. 30 ckt panels full in brand new houses. I usually badmouth the electrician and tell the homeowner how he thought he was being sly but actually spent more than he would have if he just used a 40 ckt. The homeowner usually replies with yeah, he was kind of a moron, we didn't like him but the builder used him. That's when I badmouth the builders.
 

Ken Olson

Member
Location
Rocky Point, NY
It's a 30/40 panel , what's wrong with installing tandems as long as they are rated for the use.

The panel in question is a Square D "QO" 13040M200 Load Center . . . i e 30 spaces with the last 5 on each side suitable for twins . . . Total = 40 SP breakers.. This typical house used up 3 bed AFCIs, 3 bath AFCIs, 8 spaces for the kitchen, 1 20A AFCI for the Dining Room, 4 general lighting & DRs , smokes, etc. Throw in 3 outdoor circuits + a pool. The twist outs on the cover haven't been removed and I'm already out of room - the panel ground wires are still shiny!
Maybe what I'm trying to ask, before I have to go to a subpanel,is, in NY, do I have to have 20A AFCIs in the panel for the bath circuits . . . or, can I twin them out and just go with the required GFI Receptacles in each of the 3 baths? (somebody is gonna have to make a 50 space panel in order to grow with NEC 70 reqs)
 

kwired

Electron manager
Location
NE Nebraska
The panel in question is a Square D "QO" 13040M200 Load Center . . . i e 30 spaces with the last 5 on each side suitable for twins . . . Total = 40 SP breakers.. This typical house used up 3 bed AFCIs, 3 bath AFCIs, 8 spaces for the kitchen, 1 20A AFCI for the Dining Room, 4 general lighting & DRs , smokes, etc. Throw in 3 outdoor circuits + a pool. The twist outs on the cover haven't been removed and I'm already out of room - the panel ground wires are still shiny!
Maybe what I'm trying to ask, before I have to go to a subpanel,is, in NY, do I have to have 20A AFCIs in the panel for the bath circuits . . . or, can I twin them out and just go with the required GFI Receptacles in each of the 3 baths? (somebody is gonna have to make a 50 space panel in order to grow with NEC 70 reqs)

AFCI has never been required for bathrooms in NEC.

Square D does make 60 and 84 circuit QO panels. They made them even before the 42 circuit limit was removed as they were allowed in Canada.
 

kwired

Electron manager
Location
NE Nebraska
The load on all of these breakers was less than 1 1/2 amps, way to much heat given off for such a small load.

Might not be as out of line as you may think. If you have a panel full of 1-2 amp continuous loads on every breaker it very well may operate at a higher temp than same panel with just a couple 50 amp breakers with 40 amp continuous loads. The thermal overload device within the breaker operates because of heating within the breaker. This heating is present when there is any load but increases as the current increases. 30 breakers creating a low level of heat adds up and could be more than just two with a higher level of heat given off.

Typical dwelling does not have very much load that runs continuously. Heating or cooling is the best possibility, or maybe a swimming pool pump if there is one. So you often do not notice much heating within a panel for a dwelling, except for air conditioner breaker most of the time.

Most people do not think of 15 watts as being very much. Grab ahold of the tip of a 15 watt soldering iron that has been turned on for at least a few minutes and tell me it is not hot. Just a few watts of heat in an enclosed space will start to add up.
 

templdl

Senior Member
Location
Wisconsin
What is one locked in at as far as the size of the loadcenter? Is it dependent on the service size specified, 100A, 150A, 200A? Then, what does it take to be able to step up to a 42ckt pnl?
I can remember years ago when new home were advertise with adaquate wiring which meant that it had a 100A service nd not 60A. I'm not aware what the standard service drop is but yo can be limited buy the size of the conduit used from the meter to the loadcenter and what size wire is allowed there. If my memory serves me correctly and with out getting the code book out or varifying the size of the conduit used from the meter to the load center where aluminum wire is used, using copper could allow you to go from 100a to 150a if I recall correctly with 1-1/4" conduit. Isn't a 100a service limited to a 32ckt loadcenter? Going to 150a gets you into a 42ckt by simply changing the wire from the meter to the loadcenter from aluminum to copper.
I trust that I'm not misrepresenting this scenario.
 

kwired

Electron manager
Location
NE Nebraska
What is one locked in at as far as the size of the loadcenter? Is it dependent on the service size specified, 100A, 150A, 200A? Then, what does it take to be able to step up to a 42ckt pnl?
I can remember years ago when new home were advertise with adaquate wiring which meant that it had a 100A service nd not 60A. I'm not aware what the standard service drop is but yo can be limited buy the size of the conduit used from the meter to the loadcenter and what size wire is allowed there. If my memory serves me correctly and with out getting the code book out or varifying the size of the conduit used from the meter to the load center where aluminum wire is used, using copper could allow you to go from 100a to 150a if I recall correctly with 1-1/4" conduit. Isn't a 100a service limited to a 32ckt loadcenter? Going to 150a gets you into a 42ckt by simply changing the wire from the meter to the loadcenter from aluminum to copper.
I trust that I'm not misrepresenting this scenario.

There is no limit. You could have a 100 amp main supply 1000 20 amp breakers if you wish. They would likely not all be in a single panel but could still be supplied by same 100 amp main. Size of service or feeder is determined by calculated load not how many branch circuits there is. That is what art 220 is for.
 

templdl

Senior Member
Location
Wisconsin
There is no limit. You could have a 100 amp main supply 1000 20 amp breakers if you wish. They would likely not all be in a single panel but could still be supplied by same 100 amp main. Size of service or feeder is determined by calculated load not how many branch circuits there is. That is what art 220 is for.

I agree entirely, I know the drill. My point is, what is the actual service drop size? What does the utility actualy use in real life? Is is possible that you could upsize the panel from 100a to 150a with the existing service drop without having to upgrade the service drop? What I'm looking for is some latitude in ampacity by thinking outside the box.

Who specifies the panel size? When electricians come in after the fact what is the latitude that they have to work within. They often time have very lttle to no input other than bidding to the plans and specifications and you know what happens when you start do add extras to do the job the way you think it should be done. Can you even get a 42 ckt pnl with a 100a main should you want to upgrade a 100a panel? Or are you forced to add a sub panel because you have no choice?
The electrical contractors sometimes have their hands tied when you're dealing with plans and specifications and you have had no input up front.
 
Status
Not open for further replies.
Top