Questions tagged [circuit-breaker]
The circuit-breaker tag has no usage guidance.
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1answer
42 views
What sort of protection does a 2 pole circuit breaker offer?
I am trying to understand the advantages of using a 2 pole circuit breaker. I mean when the 2nd pole is used in the Neutral line in a single phase 230VAC system. Normally they cost more so they must ...
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1answer
64 views
Device for preventing 12V battery from dying
I am looking for a device which cuts off the connection between batteries and the system just like a circuit breaker when my 12V battery goes below 9V(for example) for preventing it from dying ...
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0answers
96 views
Circuit Breakers: Do they degrade over time and start tripping? [migrated]
Sorry for the newbie question but I have a circuit breaker (Hager Series MP-E – Magnetic Switch Bipolar 30 A Curve) in my house that absolutely never tripped. This is the main CB in my house. Usage ...
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3answers
69 views
Rounding up or down with Motor Overcurrent Protection
When sizing motor over-current protection, CSA 22.1 28-200 3a states that a circuit breaker can be sized up to 250% of the rated full load amperage (FLA) of the motor.
E.g. 100hp, 575VAC motor ...
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3answers
78 views
How can I check if two outlets are connected to the same electrical circuit?
I have some internet problems, and I was thinking to buy a PowerLine, that will help me extend the WiFi range. The thing is, to get this PowerLine working, both need to be conected to the same ...
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3answers
245 views
Can double-pole breakers trip each side separately?
How many of you have used double pole breakers?
Are double-pole breakers just two single pole breakers physically joined?
Someone stated that only one side of the double pole breaker provided ...
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2answers
1k views
Help identify this breaker
I salvaged this breaker unit from the scrape yard. Compared to every other breakers i have seen before, this is very different. It has 5 terminals.
The labels are very clear but there is no ...
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4answers
3k views
Why cut both live and neutral wires?
It is a common practice, for high power loads such as boilers, furnaces, etc., to install a circuit breaker that "cuts" both live and neutral wires - at least in Europe.
In my search for EVSE, I saw ...
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1answer
93 views
240v AC Circuit Breaker for 24v AC
I am essentially intending to use this Schneider Electric A9F44120 MCB as an automatic brake for my wind turbine, which has an output of 25A @ 24Vac.
Can I use the normal 240Vac MCB for 24Vac?
Will it ...
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1answer
33 views
Can you bridge off of a 240 V Breaker Box that connects to an Intermatic Timer?
I have an Intermatic T104 Timer drawing power from a Homeline Breaker Box
for a home swimming pool. I'm wondering whether it would be considered safe to use the knockout in the timer enclosure to ...
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1answer
100 views
amp rating a circuit breaker
My application has a max Amp draw of 56@24Vdc, if I use a Circuit Breaker that is rated 60A@48Vdc, will it "trip" 60A@24Vdc? If not, what do you suggest? The Minn Kota MKR-19 Circuit breaker is rated ...
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1answer
86 views
When to use a 2 pole circuit breaker over 1 pole
We are currently designing a product that connects to 230VAC mains power (single phase) (South Africa). It has a simple 12v switch mode power supply that runs the electronics. We want to put a Circuit ...
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1answer
124 views
Full Load Amps vs General Purpose Amps
http://www.carlingtech.com/sites/default/files/documents/M-Series_Details_%26_COS_021114.pdf
This circuit breaker have two different current ratings, depending on amperage range: Full Load Amps and ...
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1answer
46 views
What's with the minimum voltage rating on *some* IEC 60947-2 MCBs?
It seems that some, albeit not all, miniature circuit breakers have a minimum voltage rating under the IEC 60947-2 scheme (often 12VAC/DC). For instance, see the Sprecher/Schuh L8 series (PDF page 8) ...
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1answer
45 views
Are there disadvantages to this method of testing building wiring after a lightning strike?
A lightning strike can damage wiring in a building. Specifically it can damage the insulation on the conductors, resulting in arcing and fire, either immediately or some time after the strike. I've ...
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0answers
162 views
Circuit Breaker Simulation in Matlab with Mayr and Cassie Equations
I'm trying to understand how to model arc circuit breaker.
There is a simulation example as called Mayr and Cassie Circuit in Matlab&Simulink.
I have examined Mayr and Cassie Differential ...
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6answers
169 views
Why can closing a circuit breaker into a short circuit result in an arc flash?
NFPA 70E 130.6(M) states:
After a circuit is de-energized by the automatic operation of a circuit protective device, the circuit shall not be manually re-energized until it has been determined that ...
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2answers
115 views
Is it possible for all circuit breakers in a panel to trip in the same time (for one fault)?
Today, I was in a hospital. Someone told me that there is a falt in a large washing machine. This fault caused all the CB's in the panel to trip.
The panel has many circuit breakers of different ...
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2answers
81 views
Automatic cut mains power on a thunderstorm
I am a software engineer with only a basic experience with electric/electronic engineering.
I live in a rural area subject to thunderstorms, my house is the end of the line from street poles. It's ...
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2answers
46 views
3 pole breaker and wire amp rating
In the main panel, there are 3 wires for 3 phase power going from 3 pole 40A breaker to a sub panel. the breaker is (CKIPSAL 4CB340/6 C40)
The wires are in 2 cables.
Each of these wires has 7 strands ...
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1answer
73 views
What could be causing this GFCI trip upon fan turn off?
I have a 2-pronged fan plugged into a GFCI in my basement. Twice now, as I was turning it off (out of maybe 30 times I have turned the fan off), the GFCI tripped.
Now, I understand that GFCIs trip ...
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1answer
55 views
Coordinated relay tripping for Protection in Modern Power System
I have been working on Etap Software to understand the basic protection scheme using Current Transformer, circuit breaker and Relays. But i am having trouble in the coordination of the tripping in the ...
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1answer
330 views
How does AFCI work?
GFCI / RCD systems are generally well documented in how they work (run both conductors through a loop of wire such that imbalance in current is measurable) -- but the mechanism by which arc faults are ...
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2answers
652 views
What is meant by the term “galvanic contact” in this sentence?
Simply speaking, a switch or circuit breaker are two metallic contacts (electrodes) that are in GALVANIC CONTACT with each other when closed and separated by a certain distance when open.
I don’t ...
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3answers
399 views
Current through protective earthing
Is there a way to estimate the magnitude of the current that would flow through the protective earthing of an electrical equipment in case of a fault?
I recently had an equipment fail in this manner ...
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2answers
959 views
What factors play into choosing type of MCB (Circuit Breaker) which is B16 vs C16 vs D16?
Found these discussions and Q&As online around this and am trying to determine how/ when one would decide to choose which way to go?
http://www.theiet.org/forums/forum/messageview.cfm?catid=205&...
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1answer
4k views
I've seen many lighting circuits protected by 100mA ELCB instead of 30mA, why is that? isn't 30mA safer?
I've seen many lighting circuits protected by 100mA ELCB instead of 30mA, why is that? isn't 30mA safer than 100mA?
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3answers
1k views
How do I protect myself when testing a PCB that involves an AC line?
I have to test prototype PCBs that convert household AC into several DC voltage levels.
I concern about my safety when working with AC and would like to know how to properly setup a testbench that, ...
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1answer
161 views
How can I power a load from two separate circuit breakers?
On one circuit breaker I have a manual switch. On the second circuit breaker I have a motion sensing switch (using a mechanical relay). I have a number of lights wired in parallel as the load. The ...
0
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3answers
80 views
Circuit breaker for single outlet
I have several 3d printers. One of them keeps tripping the breaker for the room. I'm trying to debug (obviously will not use it regularly until I can determine what is wrong) but in the mean time I ...
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3answers
2k views
Circuit breaker trip timing
I'm a little unfamiliar with circuit breaker specs and confused by this circuit breaker datasheet:
https://www.waytekwire.com/datasheet/46974.pdf
On the second page, it says that it takes more than ...
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4answers
203 views
(How) can IEC-specification miniature circuit breakers be interlocked?
A relatively common way of implementing a transfer or bypass/isolation function in North American electrical practice is to use mechanical means to interlock the handles of multiple circuit breakers ...
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2answers
288 views
Virtual AC ground for AC power main
I have the following problem: I use to perform electrical experiments in a small room in an apart where other persons repair computers. It sometimes happens that I make the main differential switch ...
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1answer
119 views
What's the use of the ground socket of an ungrounded GFCI receptacle?
Is the ground socket of a GFCI receptacle that isn’t connected to ground useful? (I'm in the United States, if it matters.) If the connected appliance had current on its ground pin, where would this ...
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1answer
464 views
Expected breaker temperature on a 208V 30A circuit with continuous 80% load
I have several cabinets of servers in a datacenter and each of these cabinets is on a dedicated 208V 30A circuit. The load on each of these circuits is 24A and one circuit is slightly higher (~24.6A).
...
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6answers
13k views
Does a circuit breaker trip depending on voltage or current?
I've have a GE 120V 20A circuit breaker. I'm aware that once it exceeds the 20A rating the breaker does its job and trips, but what happens if the current is less than 20A and the voltage lets says ...
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1answer
102 views
Why is MCCB 1000Vdc for photovoltaic?
I want to install MCCB for 750Vdc supply in traction application (Light Rail Transit). After finding some 750Vdc MCCBs, I looked for 1000Vdc MCCBs. All the 1000Vdc MCCBs are intended for photovoltaic ...
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1answer
393 views
How to prevent PV input to charge controller if battery breaker trips
I have a 20amp mppt charge controller (EP Solar tracer 20a). In the manual it states:
WARNING: Connect battery terminals to the charge controller BEFORE
connecting the solar panel(s) to the ...
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1answer
304 views
Solid state circuit breakers
I'm trying to design a Solid state circuit breaker for a 3phase AC system with a rating of 690V, 1000A. As, the stray inductance contributes to the voltage peaks in the system I'm trying to protect ...
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3answers
941 views
Residential MCB vs. Industrial MCB
Are there differences between residential circuit breaker and industrial circuit breaker? When I browse through various online catalogs on circuit breaker, ABB and Schneider Electrics are often ...
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6answers
3k views
Why Circuit Breaker has neutral and no ground?
My understanding is circuit breaker only need to trip when the hot end current jumps up (e.g. short circuit), but I have seen circuit breaker has dual (two) poles with both red cable and blue cable ...
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1answer
353 views
Is it necessary to use 4-pole circuit breaker for TN-C-S system?
It seems that in TN-C-S system is necessary to use 4-pole circuit breaker, I want to know it's correct or not? and if it's correct, which document or standard is used to prove it?
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2answers
534 views
Using motor circuit breaker buttons to start/stop motor
I want to add some protection to an ac 3/4 hp motor. I did some research and found that I could use one of these motor circuit breakers:
My question is, if I use one of these, can I use the on/off ...
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3answers
2k views
Proper setting of a magnetic trip breaker
I have separate interrupting devices in an MCC bucket. One is a magnetic trip-overload 250A breaker, where the lowest trip setting is 1100A. The other is an electronic device that has 3 CT's and ...
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1answer
92 views
Working house main Control Miniature Circuit Breaker(25A) instead of transfuse (16A)?
I have two Miniature Circuit Breaker, so one is ordinary main Miniature Circuit Breaker(house main MCB) in range of 25A and the other is my device (Auto-Transformer) in range of 16A, So when i run ...
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1answer
241 views
Optimal Breaker Configuration for Split Phase Mains Power
First, let me preface this by saying this is entirely theoretical. I don't plan to install anything myself, and I'll contract a licensed electrician to do any of this work, so please don't feel the ...
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1answer
274 views
Circuit breaker not tripping
I am powering a bunch of LEDs with a 60A/5V power supply. For extra protection, I wired a 50A circuit breaker between the supply and the LED array:
http://www.digikey.com/product-search/en?mpart=W23-...
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3answers
385 views
What happens if there was a short circuit fault BEFORE the main circuit breaker?
I haven't studied power systems yet but i keep wondering about that.
What would happen if there was a short circuit fault BEFORE the main circuit breaker(on the grid itself)? what protction is ...
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3answers
822 views
Circuit breaker automatic switcher [closed]
I have a circuit breaker for my house as this one:
Each time we turn on 3 ACs , the breaker turns the current off and I have to lift the circuit breaker switch which is far down stairs in my ...
