What would it hurt to add 1 or 2 tandem breakers in a 200 amp 40 circuit panel. There's plenty of room for neutrals and grounds. It won't overload the buss, it would be perfectly code acceptable to put 1 or even 2 or 3 - 100 amp sub panel off the same buss, so what does it hurt to squeeze in one more circuit rather than forcing a customer to pay for a sub panel? Don't just point out code referrences that disallow it, but the real harm it could cause. Thanks.
We do it all the time. If we don't our competition will and I don't consider it a safety issue.
GJ
what would it
hurt? if we expose the NEC as a document of arbitrary bench marks with flimsey rationale to substaintiate it, the NFPA may fold like a cheap K-mart table..
the trade as we know it will cease to exist
![[Linked Image]](https://www.electrical-contractor.net/ubb/rolleyes.gif)
Well Sparky, What good is the NEC if they have black and white rules that sometimes aren't safety issues. I think the NEC is needed and without it and licensing we would have a lot of unsafe conditions created. But an answer basically saying the NEC is the law, right or wrong, and we should abide doesn't cut it with me. Do you ever go a little faster than the speed limit when you drive?
The question in my mind would be where would the line be drawn,and who would draw it?
If you could add 1 or 2 why not 3 or 4?
Btw Eagle, I read an article in the AJC that said a DOT study showed that the average speed on I-285 was 85 mph. That would meanroughly 50% are going over 85 mph.
That tells me that if there were no limits,some would have a lot more than 1 or 2 tandems if they could get away with it. Just mho.
Russell
[This message has been edited by ga.sparky56 (edited 07-04-2003).]
Quite simply, absolutely nothing.
I do agree that you have to draw a line somewhere, but I see more harm in putting 5 - 100 amp sub panels off 1 - 200 amp service than adding 2 circuits to a 40 circuit panel. Yet the 5 sub panels would be allowed.
First
The 2 sparky's have, IMHO given very good answers, especially the 1st one.
Scott, I also think you are right about the bus, but another reason to think about is the gutter space. Sometimes trying to find where a wire leads to in a panel is dificult at best and unsafe, also heat dissipation is a consideration, and the manufacturers have only tested their panels to these specs.
One of the hard parts of being a concerned contractor is the consideration of a customers needs (including financial).
If you have 42 existing circuits, and you need 1 or 2 more the dilema is, new subpanel or twin breakers. It can be a tough decision, only you can make.
I will ask one more thing - What separates the professional from the nonprofessional?
Pierre
The average residential panel is generally so lightly loaded at any one time that I don't see it as much of a safety issue. The load on the bus is only going to change by the amount of additional things put on it.
You could put 20 subpanels in a 40 circuit panel, and not increase the load at all.
Eagle, is there a reason that you can't increase the # to 42 anyway??
Commercial work could be a completely different story, however.
Electure, I have never seen a residential type panel that allows more than 40 circuits.
I will ask one more thing - What separates the professional from the nonprofessional?
good one Pierre
![[Linked Image]](https://www.electrical-contractor.net/ubb/smile.gif)
i would counter that it is the ability to
scrutinize all aspects of ones livelyhood objectively
however... in doing so within the NEC we are stonewalled with benchmarks like 42 circuits, 6 disco's, 24" lengths, 30 conductors, etc
sure, someone had to make the call, it's simply easier to swallow when they come with some level of justification.
(btw~ i have long suspected a six fingered NFPA past employee of stature) do i always drive 55?, no not
really ![[Linked Image]](https://www.electrical-contractor.net/ubb/tongue.gif)
, yet i suspect that there are stats supporting the safety of lower speed limitations
[This message has been edited by sparky (edited 07-05-2003).]
[This message has been edited by sparky (edited 07-05-2003).]
I know the majority here have permits and inspections,but from someone who must justify to homeowners and Gc,s daily that what's in "that little book you pull like a knife" as one Gc phrased it,it would be nice to have some human "backup" to justify why we can't "Just do it this way,nobody will ever see it".
However I don't think there's many who can say that they haven't had to fit a fix to the situation.
Russell
I almost always am asked " Is it safe ? " when somebody wants to do an installation other than per the words in the CODE.
I usually refer the questioneer to 90.1(A) and 90.1(B), especially the " This code contains provisions that are considered necessary for safety".
Why should a ' justifiable ' decision be required when an installation is not installed per "the code" ?
In the scenario of the original question, when is just 1 or 2 more ( or 4 or 5 ) tandem CB's beyond justifiable?
The Code is not a perfect document, but it one than the electrical industry geneally adopts and allows for everyone to use the same criteria.
Why abuse it ?
Indiana indicates that all electrical installation be installed per the Indiana Electrical Code ( a modified NEC ) whether it is inspected or not.
Seems to me that the "next person will install the tandem breakers if I don't" is asking for a possible future costly reprimand.
Trouble is "Everyone makes mistakes" is just TOO easy to say, - - - me included.
[This message has been edited by Gwz (edited 07-05-2003).]
A coupleof years ago I was called to wire a hot tub at a 3 year old custom home. When I opened the 40 circuit 200A main breaker panel, I discovered 54 circuits via added tandems. This was done at the time of construction. My first thought was what other code rules did the electrician violate on this job. I started at the meter and looked at the whole system and soon found several. The metering was at the pad mount with a 320A meterbase feeding (2) 200A disconnects. One fed this house and one fed a 40'x100' workshop. Neither the house or the workshop had a grounding electrode system, just one ground rod driven at the meterbase/disconnects. The house and workshop were each fed with 4/0 URD triplex, no EGC. There is CATV, telephone and intercom wiring run between this house and workshop as well as metal water piping and copper LP gas line.
I guess the point I'm trying to make is when I see one basic NEC article disregarded, I automatically become suspicious of the rest of the job. This wasn't a must fix situation, this was wrong from the get-go on a $500,000.00 new construction project executed by a long established licensed electrical contractor in a county with no inspection program at the time.
"that little book you pull like a knife" as one Gc phrased it,
What a professional
![[Linked Image]](https://www.electrical-contractor.net/ubb/frown.gif)
"Just do it this way,nobody will ever see it".
Makes you wonder how many times he has said that with structural elements of his buildings.
I am glad I work in an area that we have regular inspection of the trades.
ga.sparky56 It sounds like your always working against the tide in your area, it must be tough not to "fall in line" with the unprofessional.
I also am glad I live in an area with regular inspections, but this one (seemingly) arbitrary rule is one I question. How can we have a 200 amp 20/40 that can take 40 circuits, yet a 40/40 panel that's more than twice the size take the same amount of circuits and not 1 more?
You have to stop somewhere. I recently bid a project to correct a non licensed "electrician's" work. This guy had a 200amp 40 circuit panel as a 100 amp sub panel off another 200 amp panel. Both panel had over 60 circuits in each. Numerous other problems were found.
I was hoping someone knew a real, technical reason for the limit. But it appears the only answer is "because the code says so." I've never liked an answer like that whether in school, or city government, or home ownwers associations, etc. That is why I questioned this rule. I don't like having to give this answer to a homeowner when they ask me why they have to spend $XXX for a sub panel to add one circuit.
Bob,it's not as bad as I make it sound sometimes.
There's several good professional builders and tradesmen of all kinds here,but the lack of code enforcement still seems to be an excuse to "do as you please" for some.
Case in point,I was in the supply house this past Wed. and a Licensed EC came in and asked for 6-3"plain" no ground. The counterman gave him a funny look,and the EC said" I see no reason to run the 4th wire when the neutral and ground is all bonded together on the range" he left for another supplier in search of 6-3 plain.
It's gotten better over the last few years but we still have a long way to go.
I don't think Electric Eagle is in any way suggesting to "just make it work".Adding one tandem breaker is along way from being unsafe imho. I know a bit about the area he works in,and I know it's very competetive there and they probably have tough code enforcement, but there again I just think that the line has to be drawn someplace.
Russell
I copied this interesting history of the 42 circuit requirment from this website:
http://www.tradeslang.com/tradeslang_oldtimer.htm Why are there only 42 circuits in a Lighting Panel?
According to Anthony Montuori, Chief Inspector for the NY Board of Fire Underwriters, a lighting panel was restricted to 42 circuits as the result of a 1928 fire at the Waldorf Astoria. The cause of that fire was determined to be from an electric panel wired with type "R" cable whose overall heat load caused the fire. The electrical apparatus of the time could safely handle a 42 circuit panel while a larger panel could not.
well then,
if it's good enough for 75 yr old
Waldorf Astoria standards.....
Come on up to Canada. No such limit here.
I have trouble accepting that there's lots of remaining room for wires- especially if the neutral bus is also the ground bus, and romex is used.
Tracing circuits, and identifying wires, is always an issue, especially when a neutral is part of a multi-wire branch circuit.
It may be more of a design matter, but there is a real benefit to having circuits grouped logically, and a panel readily accessible to the area it serves. Today's kitchen alone sensibly calls for at least eight circuits- doesn't a subpanel begin to make sense?
I'm tired of seeing people spend $$$$ to get appliances in exactly the right shade of off-white, then begrudge the $40 a subpanel costs. I'm also tires of tracing circuits that meander through a house like a drunken spider, and are tapped into in seemingly random intervals.
I see no reason to limit lighting and appliance branch circuit panels to 42 poles. This limit does not apply to power panels and I would think that if there was a real safety issue the same hazard would exist in both types of panels. As long as the main bus in the panel is protected at or below its rating and as long as no single bus tap is overloaded, I don't see a safety problem. Yes, it is a violation of the current code to install more than 42 poles in a lighting and appliance branch circuit panel, but maybe it is time that the code be changed.
Don
Homeowner called us to fix his panel. When I asked what the problem was, he said the home inspector told him there were too many circuit breakers in the panel.
We found 4 tandem installed, told the owner that it was a violation. His respond was Ya I know, after the home inspector told me I checked with the town inspector and he told me it was a violation, and I should call an electrician. The homeowner wanted to know if all the electricians around here know what they are doing.
So you can see this type of just one more breaker can harm the whole basket of apples.
ALthough some rules seem arbitrary, I think many are instituted in order to formally "draw the line" somewhere.
As mentioned earlier, if we leave it up to individuals to make field judgments regarding certain situations, there is an infinite range of interpretations, and rationalization.
Just for fun...
Of the guys who see no problem with installing minis in a 40 ckt. panel, how many would you be willing to install?
(No condescension, or patronization intended, just a social experiment.
)
Redsy,
I think 2 circuits over should be allowed. This is what would be required to add a sub panel without moving circuits to the new panel. Although I can see an arguement for 4 circuits.
Like I said earlier, if a 20/40 panel is half the size of a 40/40 panel, why should both be limited to 40? Just because?
You must have a limit and I think for new work the limit should be the manufacturers rating. I think there should be an exception for alterations.
John, You install a sub panel for $40? That may be what the panel cost, but what about the 100 amp breaker, the feeder wire, the labor involved? We charge a minimum of $350 to our best contractors and it goes up from there depending on the brand and distance from the original panel. So a $12 tandem breaker looks a lot better.
Not to be a buster, but something to think about.
One guy would say adding 2 circuits is fine, another guy says, hey 4 is okay I have done this plenty of times before.
Today I was at a residence and there were 68 circuits in the 200 amp panel (200amp service). This guy thought this was okay. The reason for the 42 ckt limitation is as was posted earlier - Waldorf fire- and that has been the position since. If we don't draw the line and follow the 'minimums', then we see installation like this 64 circuit panel (this job was inspected, maybe the inspector believes it is okay too). There was so much 'stuff' in this panel I didn't know where to start.
I will say that I do not always believe some parts of the code is necessary, but I follow them because I believe that it is what separates 'US' from THEM THAT DON'T CARE.
Pierre
I think I recently saw a Cutler-Hammer 200-amp residential panel with 42 spaces.
(Not the ones with 42 twist-outs and 40 spaces...oops
![[Linked Image]](https://www.electrical-contractor.net/ubb/biggrin.gif)
, but a full 42 spaces)
[This message has been edited by Redsy (edited 07-10-2003).]
Why does this so called safety hazard only exist in lighting and appliance branch circuit panels? There is no limit on the number of poles that can be installed in a power panel. See 408.15.
Don
I imagine the tandem breakers you're talking about are the twin style type. 2-15, or 20A type. The panel has to be designed to accept them. The diagram (on the panel door) will let you know. Another give away would be the bus would be notched at these locations. If not, the full size must be used. I'm refering to Murray,
and some Croise Hinds. I may be wrong in the spelling. I would hate to be the guy that worked in the panel last and created a Fire Hazard.
What happened to the second paragaraph of 408.15? "A lighting and appliance branch circuit panelboard shall be provided with physical means to prevent the installation of more overcurrent devices than that number for which the panelboard was designed, rated, and approved."
Are you guys finding ways to beat this requirement, or are the manufacturers not reading the Code?
Another feature UL tests for is wire bending space, and any circuits beyond what the panelboard is rated for is going to also violate the wire bending space.
Creighton
Creighton, apparantly most of the manufacturers haven't read that section. The tandems for Square D and Cutler Hammer will fit on any spot in any of their panels. Siemens makes tandems that will only fit on spaces designed for them, but also makes one that will fit any spot in their panels, Murray, ITE, Gould, Westinghouse, Challenger, and GE. These are labeled "for replacement use only".
Don
Have you ever seen any panel board listed for more than 42 circuits? If so could you please post the manufacturer's site so we can take a look? Thanks
Pierre
Electric Eagle
I install many Square D (QO & Homeline) and Cutler-Hammer loadcenters and the tandem breakers will NOT fit in any position. You must be using the old style breakers that are for replacement use only. The QO tandem breakers have a hook on them that will only fit in designated positions and the Homeline/Cutler-Hammer BR Breakers have a clip on the end of the breakers that will only fit on notched busses. I don't use any Cutler-Hamer CH so I don't know how their CTL feature works.
Curt
It seems to me, it is this idiot-proof mentality we have, not unlike being politically correct. I think like anything else, the nec goes over board. Arc-faults! All kitchen counter recept's to be gfi, no matter what the distance from the sink is. Marketing maybe ?$?$?$? The 6 switch per service rule, is that for derating reasons?? As for the tandem breakers, it is getting to the point where any house above 2500 sq. ft, requires twin 150's, not because of the load, but because of the circuits required to be dedicated. Dont get me wrong, I agree with the dedicating, but as for overloading a service, that is what calculations and main ocp's are for.
John
[This message has been edited by scjohn (edited 07-12-2003).]
Pierre,
I have installed GE and Square D power panels that had more than 42 poles. This
Square D document shows 54, 72 and 84 space panels, but notes that the 72 and 84 space panels are for use in Canada only.
Everybody likes to bring up the issue of power panels. I think they are not included because most of them don't have the ampacity for a large number of circuits. Most of the ones I've seen usually have a maximum of 12 breakers in them bucause the continuous load uses up all the capacity.
Curt, you can break out the limiting parts in a Square D panel, and put in anything you want. All it takes is a screwdriver, and a hammer.
What a shame...S
you'll please excuse me if i post today's e-mailing that seem to befit this thread....
Please join me in saying good-bye.... Today we mourn the passing of a beloved old friend by the name of Common Sense who has been with us for many years. No one knows for sure how old he was since his birth records were long ago lost in bureaucratic red tape. He will be remembered as having cultivated such valued lessons as knowing when to come in out of the rain, why the early bird gets the worm and that life isn't always fair.
Common Sense lived by simple, sound financial policies
(don't spend more than you earn) and reliable parenting strategies (adults, not kids, are in charge).
His health began to rapidly deteriorate when well-intentioned but overbearing regulations were set in place. Report of a six-year-old boy charged with sexual harassment for kissing a classmate, a teen suspended from school for using mouthwash after lunch, and a teacher fired for reprimanding an unruly student, only worsened his condition. It declined even further when schools were required to get parental consent to administer aspirin to a student but could not inform the parents when a student became pregnant and wanted to have an abortion.
Finally, Common sense lost the will to live as the Ten Commandments became contraband, churches became businesses and criminals received better treatment than their victims. Common Sense finally gave up the ghost after a woman failed to realize that a steaming cup of coffee "was hot," spilled it in her lap, and was awarded a lot of money.
Common Sense was preceded in death by his parents, Truth and Trust; his wife, Discretion; his daughter, Responsibility; and his son, Reason. He is survived by two stepbrothers; My Rights and Ima Whiner. Not many attended his funeral because so few realized he was gone.
Author Unknown
As Don says, only lighting and appliance panels are to be limited to 42 spaces. If by adding one or two mini's would not the number of total Breakers grow to 43 or 44 ? Which would violate the 408.15.
As far as the power panel goesby definition is to have 10 percent or less lighting and appliance circuits. and the rest are to be power circuits.
As far as putting in the minis I have seen electricians remove the 'fail-safe' installed in Siemens minis, and break-out the plastic in Square-D(homeline) breakers just to make them fit. This goes along with the statement of 408.15 that these panels shall be provided with a means to prevent the installation of any such breakers.
But doesnt this come down to picking and choosing the rules we comply with. In that case we could cram what 84 breakers into a 42 space panel, now that would be over stuffed.
WmColt
Boy,
Only one response to my survey.(Thanks, Eagle).
I'm heartbroken.
Electric Eagle ---
After reading all of the discussion, there is no reason for the limitation.
If the code wants to solve a problem, such as too much heat generated in the panel, it should tate the goal and let people solve the problem according to the particular circumstances.
According to the code I could put a 60amp service in and have 42 circuits in the panel. Or I could put a 200amp service in and have the same restriction.
There is something wrong with the code when those two situations are both limited to 42 circuits.
I have used tandem breakers. I only use them after an amp reading with all loads on in the building. If the actual load will allow the main to still be under 80% of rated capacity, I do not see a safety issue.
I have also turned down jobs were continual additions have maxed out the main panel and the owner would not go for a new upgraded service.
This is a judgement call based on the actual load possible. I think that our training and professionalism can allow us to make those calls. I also get the local AHJ involved when necessary and when he is compentent to help.
(We still have a few grandfathered all in ones around here, some of whom have never opened a NEC code book. Fortunatly almost all will retire soon.)
Lets face it, a major part of our job is to be THE electrical expert for our customers. We owe our customers our livelihood and our business sucess. Thier lives and property depend on our work. A fire or shock caused by something we did is a violation of that trust they have in us. Knowing and using the CODE is our responsibility.
Make your own judgements and good luck
The way I've always looked at it is if the labeling instructions say not to do something I won't do it. I don't understand all the reasons why, but just don't want the potential liability.
My understanding is that if anything ever goes wrong with an Electrical system someone has worked on and they see one thing done against code or UL Listing that person will be on the short list when Ins. Companies go looking to recover for damages. Remember, even if you're innocent it costs money to defend yourself. Why open yourself up to that?
Bill
My answer to customers when they ask "What would it hurt?"<
I tell them straight........"If anything happens, like a fire, overload,damaged equipment,electrocution, ............the LAWYERS are going to come after ME"......
I don't need the Liability.
[This message has been edited by rowd (edited 09-04-2003).]
Liability??
90.7 Examination of Equipment for Safety.
For specific items of equipment and materials referred to in this Code, examinations for safety made under standard conditions provide a basis for approval where the record is made generally available through promulgation by organizations properly equipped and qualified for experimental testing, inspections of the run of goods at factories, and service-value determination through field inspections.
This avoids the necessity for repetition of examinations by different examiners, frequently with inadequate facilities for such work, and the confusion that would result from conflicting reports on the suitability of devices and materials examined for a given purpose.
It is the intent of this Code that factory-installed internal wiring or the construction of equipment need not be inspected at the time of installation of the equipment, except to detect alterations or damage, if the equipment has been listed by a qualified electrical testing laboratory that is recognized as having the facilities described in the preceding paragraph and that requires suitability for installation in accordance with this Code.
FPN No. 1: See requirements in 110.3.
FPN No. 2: Listed is defined in Article 100.
FPN No. 3: Annex A contains an informative list of product safety standards for electrical equipment.
If a panel is full it is full. To install a tandem is not only against code but a denial of the problem at hand. If you had seen a receptical with a broken top would you have fixed it or just told them to use the bottom? If the panel is so full that you could not fit another in it, it's time to upgrade or expand the service. If the client wants a reason why it is for their own safety, the safety of the property and your peace of mind that you did not add to the problem most of us are faced with daily. I would not want to imagine the world without the nec and even if I do not personally agree with each one of them, I do have to take my hat of to them for what they stand for.
i didnt read every reply so this may have been covered already:
i have added a tandem breaker or two and exceeded the limit. nothing negative will probably ever happen as a result. but that was back when i was naive and un-defiled by genuine meaness.
nowdays, instead of giving the standard answer, 'because the code says so' i say 'because if anything EVER goes wrong i'll be liable'. that usually ends the discussion. lol
(i should add, there are people who will ask for work done without inspection and not up to code and when a money dipute arises, use that fact against you. in a nutshell, it aint worth it.)
[This message has been edited by targetshootr (edited 09-05-2003).]
That's also my standard response targetshtr.My home area has no inspections so it's not umcommon to see strange things here.Oftentimes the NEC must be"sold" to gc and homeowner alike to justify things like no porceline lampholders in closets,gfci receps etc.
Russell
I thought by Section 384-20 that you can only put one neutral conductor per set screw on the neutral bar and no more than three equipment grounding conductors per set screw on the ground bar.
Maybe we could use this to limit the number of circuits in a panel.