circuit breakers - how old is too old?
- Thread starter olc
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This is area that has been hotly debated to no end. That being said, while mechanical devices such as these can degrade to an extent with age, there is no reason to think that a standard mag cb that has not been tripped repeatedly, would need replacement within the window of, imho, 50 years or so. Of course, certain brands (fpe,zinsco cb panels) need to be given the heaveho anyway.
I stated here recently that some fpe noark stuff from the '50s seem to function ok, but those panels are in their 6th decade of service, and have probably outlasted their intended life expectancy-they may not open as quickly as they could have in 1961, if at all-the thermal trip aside
As for replacing the entire panel board, I say that depends solely on condition and if it will meet the demands of the building for the foresseable
future. If you can't get those replacement cbs anymore or if the replacements would be costly ("generic" fpe) , the relic needs to go, simple as that.
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- Location
- San Francisco Bay Area, CA, USA
- Occupation
- Electrical Engineer
No rule of thumb, other than testing and finding problems, which is usually not practical for anything but large breakers (i.e. not residential stuff).
Maybe, if by "function" all you mean is pass current and trip on over current. I routinely see breakers still in service that are from the 40s and 50s. But with extreme age comes the risk that when needed most, they don't hold together when they DO trip and become shrapnel. You won't know until after it happens.
Only in that some brands were bad from the get-go, hence they no longer exist.
I would. There are almost always people willing to sell old obsolete breakers, but unless you can get a certified test report saying they have been tested and function (not just cleaned and switched), it's a risk you have to weigh against the cost to swap out the entire panel. Breaker brokers will not go to the expense of testing and certifying anything small.
DrSparks
The Everlasting Know-it-all!
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- Madison, WI, USA
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- Master Electrician and General Contractor
Testing equipment is expensive and the cost of a new panel and/or breakers (for residential applications) is worth the peace of mind that your house isn't going to burn down because a breaker failed.
:thumbsup:. Exactly. It reaches the point where there isn't any use in trying to continually revive/repair something that belongs in a museum if the customer can afford to ditch it.
Jraef also has an excellent point about used cbs-if at all possible stay away from them.
DrSparks
The Everlasting Know-it-all!
- Location
- Madison, WI, USA
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- Master Electrician and General Contractor
It also depends on the panel/breakers. I would be less likely to feel a sense of urgency about replacing an older QO panel than I would about say a Federal Pacific or Wadsworth.
petersonra
Senior Member
- Location
- Northern illinois
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- engineer
my personal opinion is that at some point it makes sense to rehab a house. when you do that, it is probably a good idea to replace the plumbing and the electrical systems. you might get another 50 years out of them, but you never really know.
DrSparks
The Everlasting Know-it-all!
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- Madison, WI, USA
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- Master Electrician and General Contractor
Especially if you have old galvanized steel plumbing!
- Location
- Wisconsin
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- PE (Retired) - Power Systems
I believe UL had done some testing of residential products, several years back. The results were available, for a while, but I don't think there was ever a formal report.
The answer partly depends on if the circuit breakers are small molded case ones, like found in residences, versus >800A ones found in industry.
The answer partly depends on if the circuit breakers are small molded case ones, like found in residences, versus >800A ones found in industry.
Other that doing a factory calibration test what it amounts to is an opinion. The UL489 testing requirements are quite vigorous which relate to mechanical and electrical testing.
The only thing that I could recommend is to exercise the breakers, turning them on asnd off numerous times.
This helps to assure that the mechanisms lubrication is distributed and that the movond and stationary contacts close together well.
When the moving contact closes against the stationary contact it actually rubs against the stationary contact to promote their proper seating against one another.
As for as the thermal and magnetic elements are concerned those won't deteriorate with age. It's just the mechanism and the contacts.
The only thing that I could recommend is to exercise the breakers, turning them on asnd off numerous times.
This helps to assure that the mechanisms lubrication is distributed and that the movond and stationary contacts close together well.
When the moving contact closes against the stationary contact it actually rubs against the stationary contact to promote their proper seating against one another.
As for as the thermal and magnetic elements are concerned those won't deteriorate with age. It's just the mechanism and the contacts.
Often times those breakers aren't operated in years if ever unlike those residential load centers.
It may be an inconvenience by exercising therm at lest once a year would help to assure that the mech is lubricated and that the contacts make good contact with one another. It is of my opinion that this is the most neglected part of a maintenance procedure.
MasterTheNEC
CEO and President of Electrical Code Academy, Inc.
- Location
- McKinney, Texas
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- CEO
There is no Rule of Thumb and you will never see a manufacturer give an End of Useful Life Statement on things like this. What contributes to the answer of when to replace is it's exposure and how it is used. A typical circuit breaker that has been tested and evaluated should long outlast you and me...it is designed for the normal exposure it gets. However, when they are exposed to things outside of the norm then anythings life can be shorter than expected. That's why us Electricians get paid the BIG BUCKS...to field evaluate and make determinations based on real life exposure.
MasterTheNEC
CEO and President of Electrical Code Academy, Inc.
- Location
- McKinney, Texas
- Occupation
- CEO
Those to me would be the least of my concern unless again they are located in areas of elevated exposure that would warrant the concern over time. In a normal situation it is not something I would be concerned with in terms of their ability to function. However, thats just my take on it as I am sure others will disagree....and we all know I support buying more Electrical Equipment if you deem you need it:angel:
And in the case of an outdated 6 circuit panel board stuck in 1955, most of the time your wish shall be granted!
donaldelectrician
Senior Member
Life of Circuit Breakers
Life of Circuit Breakers
You see me post about , " Edison Base Fuses " .
Still the best OCP and I trust the fuses to last .
I will have Edison Base Fuses in my Cabin ... Third World .
Don
Life of Circuit Breakers
You see me post about , " Edison Base Fuses " .
Still the best OCP and I trust the fuses to last .
I will have Edison Base Fuses in my Cabin ... Third World .
Don
Lets compromise-you keep your fuses, but we still get to trash the wadsworths and zinscos.
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