25A breakers

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southernboys

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just went out on a service call for tripping breaker. the customer has a 20A breaker that is pulling 20A. she tried to put a radio on this circuit and breaker tripped. Im wondering theareticaly if I could put in a 25A breaker in place of this 20A breaker? I know its against code but this would be a lot easier then trying to repull a new circuit. would this create any great danger thanks for your input in advance
 
Re: 25A breakers

:mad: yes it creates at least 2
first one is you could and should have your license pulled
second one is you might cause a fire

You know the code answer so why would you even think of doing this.So what if it takes all day to run another circuit.Isnt that what your in buisness to do.
 
Re: 25A breakers

It creates great legal danger for you. You will have to run a new circuit or split the load off to other less loaded circuits.
the customer has a 20A breaker that is pulling 20A. she tried to put a radio on this circuit and breaker tripped.
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Did you put an amp clamp on this circuit? How long after the radio is turned on does the circuit trip? The trip curve for a major brand of 20 amp breakers shows that the trip time for a 25 amp load would be between 45 seconds and never.
Don
 
Re: 25A breakers

since ive getting my head bit off i will be running a new circuit for this customer which i had originally wanted to do but see didnt like my price as soon as i mention fire she will see it my way. can someone help me understand if the ampacity of #12 thhn is 30a acording to table 310.16 why the overcurrent protection can only be 20a according to 240.4(D) i know to derate the 310.16 ampacity by 310.15(b2a) i just dont get 240.4 rule and yes I put an ampclamp on the wire it wouldnt trip for me but I know a breaker should only be loaded to 80% of its rating
 
Re: 25A breakers

Don't forget that by article 334, you can only load romex to the 60?C rating of 310.16.

It's a safety issue. Would you feel comfortable with a piece of romex being loaded until it's conductor temperature is 194?F? I sure wouldn't.

Hey, heads only get bit off when it's serious. This is serious. :)
 
Re: 25A breakers

I've heard from a few different people now that the NEC allows the next breaker size in "certain" Nuisance tripping situations although I have no idea if this is true or when it would apply. :confused:

A new 20 amp breaker might even solve this problem. They can get weak over time.
Is this something that just started happening with no changes in the power useage? They might just be overloading it with Heaters at night or something.

Dave
 
Re: 25A breakers

southern - even another reason to not do it -
you cannot put 15A & 20A recepts. on 25A branch ckts. for this application !!
 
Re: 25A breakers

Originally posted by dillon3c:
Your aware of the fact your in the most visited, and most popular - Electrical Code Form Site- in the US...Right.?
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:D LOL

Kind of like going to the police and asking them to back you up for speeding. :p
 
Re: 25A breakers

Originally posted by jimwalker: Was it told to you by someone you trust ?
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Well...he's been retired for many years now and although I trust his knowlege about Elec.theory, I stopped listening to his NEC "Interpretations" years ago! I really just think it's strange that another person said basically the same thing. It might have been something from "back in the day" but I think they have just misunderstood something in the 430 articles. And like you said they do not apply to this situation at all.
In fact, I'm sorry I even mentioned it!!! :)
 
Re: 25A breakers

A radio would only pull an 1 amp of power or less. I would suspect there could be another problem. I agree with the others split the circuit but would amp probe after you split the circuit to see if there is something causing it to spike as an intermitting fault.
 
Re: 25A breakers

If you think that there is an intermittent short circuit you need to do a 500 volt or 1,000 volt megger test. You would need to unscrew all light bulbs, disconnect GFCIs, and disconnect all fluorescent ballasts, not just the electronic kind.

Also, the 20 amp limitation for #12 copper revolves partly around the matter that binding screws have more than their fair share of terminal resistance and heating.

There are some instances in a factory where I protected a 10/3 UF temporary line with a 35 amp fuse to avoid extra heat due to fuse reducers which does slightly abuse the article 430 exception for motor circuits. Theoretically, a factory that does not have combustible dust can use open wiring on insulators - crane runway conductors are a form of open wiring on insulators.
 
Re: 25A breakers

You might even find a free repair.Perhaps there is something plugged in on this circuit that could be pluged into another outlet,lowering the load on the one needed.What exactly is on it now ? could some of the load be removed by using the new compact florecent light bulbs ? This sounds like a heavy load for a normal house.
 
Re: 25A breakers

jwalker it is not a house it is an office building she has a copier two computors a lap top (sometimes) a charger for her walkie talkies. plus several of those multiplug strips. I think what im going to try to do is pull a new circuit to her copier and maybe one computer. Im hoping to use the existing emt to pull my new thhn wires through. and make joints on old hots to pass it to midway point of circuit thanks to old who have replied any other suggestions would be appreciated especially price as this is the hardest thing for me to do as I only do my own jobs on the side
 
Re: 25A breakers

Your problem is not the circuit, it is the load.
Take a look at the load items first:
Copier - may require its own circuit per manufacturer's instructions
Computers - OK, but watch the amp load with several computers and peripherals
Chargers - Personally I would not like that on my computer circuit, but that is me. Maybe find another location for these.
Several Multi Outlet strips - ????

Lighten that load. Add circuits. More than one most likely. Rearrange or relocate loads.

There are many things that you could and should do, but increasing that breaker is definitely not one of them (as stated by everyone else that replied).
 
Re: 25A breakers

Originally posted by davedottcom: I've heard from a few different people now that the NEC allows the next breaker size in "certain" Nuisance tripping situations
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This is not a "nuisance tripping situation." Rather, it is a "breaker doing its job situation."
 
Re: 25A breakers

Originally posted by southernboys: I'm wondering theoreticaly if I could put in a 25A breaker in place of this 20A breaker?
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Yes. If the wire is #10 THHN. If it is, as you appear to be saying, a #12, then the cheapest solution is to replace the breaker with a new 20A (in case the old one is just too old and tired - I know that feeling :D ), and to tell the customer that she must exercise more discipline concerning using too much of her "stuff" at the same time.
 
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