I think they will trip at any amperage, GFI. They are suppose to trip if the ground carries the current, indicating a short, instead of only the black and white leads. ARC fault is a different matter altoghther and is problematic from what I understand.
Totally agree with that. I had a breaker triping problem in the hot summer, using the same power tools, that went away when the temperature cooled off. Winter, Spring, and Fa, there was never a problem.
Unfortunately I have experienced it with my new house and the replacement breaker. On a 20 amp dedicated circuit with a small freezer, and a compressor. One a week when both would come on at the same time the breaker would trip. Continued with the replacement. The solution was to put one on another circuit. Connections at breaker box and recepticle are tight. The electrician hinted at the solution and the problem... ;~(
Not if "the ground carries current", rather, if *not* only the hot and neutral (black and white). If there is a leakage path somewhere else they will trip also. IOW, the ground wire has nothing to do with it.
Wouldn't surprise me, though GFCI had a lot of teething problems, too. Those are pretty much gone now, so you can assume that you have a problem if there's a trip.
Why do you say that that was a problem with the breaker? Sounds normal to me.
Compressor max load, 15 amp, Freezer max load according to repair technition
2 amp. Well under the 20 amp rating.Compressor does fine on a 15 amp circuit. I suspect that the freezer pulls much more than 2 amps and according to the electrician I really don't have a breaker problem according to industry standards. He listed a host of brands of breakers and their designed trip points. Most all according to him trip at 80% load. He indicated that they ain't like they ust'a be. A couple on his list would trip at the designated amp rating however they are terribly expensive and or no longer in business.
----------------------------------- Thermal-magnetic c'bkrs are designed to carry 100% of name plate rating on a continuous basis in free air.
Mount the c'bkr in an enclosure and a 20% thermal de-rate applies.
A load center (panel) is considered an enclosure.
Thus the following applies:
15A c'bkr will carry 15(80%) = 12Amps continuous20A c'bkr will carry 20(80%) = 16Amps continuous
30A c'bkr will carry 30(80%) = 24Amps continuousNo magic involved, just basic engineering.
Lew
The startup current exceeds the running current for these sorts of devices by several times.
The compressor may draw 50A when it starts.
That all sounds in line Lew.
Understand that start up is greater than running speed however it seldom tripped a 15 amp breaker in my old home when it came on and a 15 amp router, dust collector, and radio were all already running on the same circuit. Come summer time that was another story.
You said: "One a week when both would come on at the same time the breaker would trip."
The one starting while the other was running (or worse, both starting simultaneously) was enough to trip the breaker. Both running is not. I would expect this sort of behavior. The breaker in your old house may not have been working at all.
At the new house with the new breakers. Previous comment was about older house.
Typically I would have the router, dust collector, and radio running. Then the compressor would cycle and trip the breaker only in the summer months, but never did in the fall through spring months.
I'm no electrical engineer and I'm just thinking out loud..... Summer months are high load months for the electric company, so maybe there is a slight voltage drop during those times.... ie: from 125+ down to 115- ????
Circuit breakers do not measure amperage so to speak, they measure temperature in the breaker. If the amperage draw is too high it gets hot and trips. In the summer it is already warm and the added load trips the breaker more quickly. During the cooler months the breaker has to warm up more before it trips. We are only talking momnets but it only takes moments for a motor to start up. Think of a circuit breaker as a reusable fuse.
Better?
----------------------------------- Only partially true.
C'bkrs found in buildings are thermal-magnetic devices.
The magnetic portion of the c'bkr measures the inrush current and responds instantaneously to a fault condition independent of temperature.
If a c'bkr trips when a load such as a motor is first turned on, the magnetic portion of the c'bkr is responding to the inrush conditions.
Mean while the thermal portion of the c'bkr responds to the long term conditions of the circuit such as when an overload on a continuous basis exists.
Circuit conditions maybe be such that it may take several minutes for the thermal portion of the c'bkr to trip.
Overload current vs. thermal trip time is an inverse ratio.
This explains why you can temporarily overload a table saw during a cut and not trip the c'bkr, if you do it quickly enough.
-----------------------------------
-------------------------------- The above correctly describes only the functioning of the thermal portion of a c'bkr.
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--------------------------------- The above describes only the magnetic portion of a functioning c'bkr in a round about way and should not be confused with the thermal function of a thermal-magnetic c'bkr.
All of this discussion helps to explain why 15A c'bkrs protecting #14 AWG wiring are basically a total waste of time in today's buildings, and especially in the shop.
The electrical demands of today are much higher than they were 50 years ago and 15A ckt's are simply inadequate in today's world. .
Lew
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