FPE Breaker, Amperage & Time

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I recently replaced a faulty FPE with a new breaker. On this kitchen circuit was a 1500w micro, 1800w toaster, stove fan & light. I explained to the owner that running these appliances will trip the 20 amp breaker.
To demonstrate, I place my amp meter on the circuits wire and turned on the micro and toaster. The meter read 29 amps. I waited (~1 minute). Nothing.

My question: At what amperage and at what time will a breaker trip? Or could this be a faulty (new) breaker?
 

augie47

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Location
Tennessee
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State Electrical Inspector (Retired)
Since it was an FPE breaker, you could have gone ahead and plugged in the coffee maker also and brewed/drank a cup of cofee while you waited ;);)
 
Very funny. I must of posted this in the comedians forum not the Mike Holt's Forum.

Weeks back, just after the new owner bought the duplex, I did try to sell an upgrade of the FPE box. At the time, he chose not to.

But seriously folks:
Are NEW FPE breakers just as likely to fail as old breakers?
At what amperage should a 20 amp breaker trip?
 

jim dungar

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Location
Wisconsin
Occupation
PE (Retired) - Power Systems
Seriously,

30A will take many minutes to trip any 20A device, be it a breaker (Eaton CH120 about 10 min) or a fuse (Bussmann FRN-R20 takes about 5min).
 

480sparky

Senior Member
Location
Iowegia
.............Are NEW FPE breakers just as likely to fail as old breakers?

Where are you getting new ones?

At what amperage should a 20 amp breaker trip?

Anywhere between 22 amps and the available fault current. Depends on the current.

TripCurve.jpg
 

G._S._Ohm

Senior Member
Location
DC area
running these appliances will trip the 20 amp breaker.
The meter read 29 amps. I waited (~1 minute). Nothing.
At what amperage and at what time will a breaker trip?
From the generic graph shown, 29/20 = 1.45 =~1.5 rated current, so between 100 and 350 seconds.
By expanding the image on your screen and using a ruler and a calculator you can measure the endpoints of this interval even more accurately, but it's probably not necessary.
 
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jim dungar

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Location
Wisconsin
Occupation
PE (Retired) - Power Systems
Here is one method suggested to test breakers.
There is no reasonable way to field test the long time trip rating of small thermal magnetic breakers. Simply loading them up to 200% is not accurate.

Among other things, the trip curves are based on a specific ambient temperature, if you conduct the test at any other temp, the tripping time will be affected and there are no published adjustment factors.
 

480sparky

Senior Member
Location
Iowegia
I thought home depot or Lowes was selling new FPE breakers. I don't know who makes them but they are something like $20 each for sp breakers

It's possible, but I never shop for Fire Producing Equipment breakers so I wouldn't notice them even if they did sell them.
 

curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
Occupation
Electrical Contractor
US retailers sell replacement Stab-loc breakers manufactured in China for Connecticut Electric. You are not going to find any new breakers manufactured by Federal Pacific Electric unless they are really old new stock. In Canada Schneider Electric (owner of Square D) markets the Stab-loc design and it is one of the most commonly used today.
 

G._S._Ohm

Senior Member
Location
DC area
Among other things, the trip curves are based on a specific ambient temperature, if you conduct the test at any other temp, the tripping time will be affected and there are no published adjustment factors.
Publishing a trip curve that is valid over an ambient temperature interval should have the effect of thickening the band on the graph.

Or, if the temperature coefficient of the breaker is known the curve could be corrected for other temperatures but this kind of detail is probably rarely published by CB manufacturers.
 

Dennis Alwon

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Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
It's possible, but I never shop for Fire Producing Equipment breakers so I wouldn't notice them even if they did sell them.

Here is a picture of the new FPE breaker from Home Depot. Looks like it is made by UBI???? By the way, this breakers is a dp 30 and runs almost $70.00

8cf91096-599b-4c0f-bbba-541876893941_300.jpg



The HACR-rated Federal Pacific Thin 30 amp 1 in. Double-Pole Type F UBI Replacement Circuit Breaker is designed for use with Federal Pacific load centers. It can be used with applications up to 13,200 watts, such as hot water heaters, clothes dryers, air conditioners (240-volt, up to 36,000 BTUs) and 240-volt, 1-1/2 - 3 HP electric motors.

For typical applications up to 13,200 watts
#10-3 copper with ground wire
120/240 VAC
Type F for use in Federal Pacific load centers
Use with 240-volt, 1-1/2 - 3 HP electric motors
HACR rated
MFG Brand Name : Federal Pacific
MFG Model # : UBIF0230N
MFG Part # : UBIF0230N
 
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Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I recently replaced a faulty FPE with a new breaker. On this kitchen circuit was a 1500w micro, 1800w toaster, stove fan & light. I explained to the owner that running these appliances will trip the 20 amp breaker.
To demonstrate, I place my amp meter on the circuits wire and turned on the micro and toaster. The meter read 29 amps. I waited (~1 minute). Nothing.


My understanding is that the DP breakers from FPE were the main issue. I don't believe the replacement ones are an issue. I would think that the issues from years ago do not exist in the new breakers.
 
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