Questions tagged [circuit-breaker]
The circuit-breaker tag has no usage guidance.
58
questions
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0answers
41 views
Protection Devices in DC ciruits
I am putting together a design for a custom Electrical panel. The panel consists of mainly DC powered components (Sensors, Controllers). Components are to be mechanically positioned using a DIN rail.
...
0
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0answers
9 views
Why do type 2 SPD’s* require overcurrent protection (*load side, mains, Surge Protection Devices) [migrated]
Bought a house built in the 1970’s in a 1970’s neighborhood. It has a 200AMP main panel. A serviceman replacing 1 of the 2 mainboards in the refrigerator suggested that I install an SPD inline in each ...
0
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1answer
56 views
Switching Power Supply - Type of MCB for Inrush Current
it's regarding this PSU from Mean Well:
https://www.meanwell.com/Upload/PDF/LRS-350/LRS-350-SPEC.PDF
It has a 60A inrush current. My lighting circuit (1.5mm2 wiring) is tied to this PSU supplying ...
0
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1answer
42 views
Switching Power Supply - Inrush Current, Input Current, MCB
I am getting several PSUs (LRS-350-24) from Mean Well. Here's the specs:
https://www.meanwell.com/Upload/PDF/LRS-350/LRS-350-SPEC.PDF
1) The input current is stated to be 3.4A/230VAC at 88%. 350W ...
0
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2answers
34 views
24V LED Strip Circuit - Switch, Breaker & Wiring Size Requirement
I am running a long LED strip (24V, 21 meter, 0.6A per meter, so technically 13A).
The 24V PSU supplying power to the strips is to be connected to a switch that is rated 240V, 10A & 2400W.
...
0
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1answer
49 views
Tripping a circuit breaker when using a half wave rectifier
How does a half wave rectifier or phase control dimmer affect the triggering of a circuit breaker? For example, if a 20A resistive load was on a 15A breaker with a half wave rectifier. Now average RMS ...
0
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2answers
38 views
Both fuse and circuit breaker operated
Is there a reason that both a fuse and a circuit breaker would operate? From my understanding, the fuse should blow first and kill any current flowing through it leaving the breaker intact. So why ...
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0answers
33 views
Modeling the thermal part of the Time-current curve
G’ day,
I am working on designing protection devices for my research work and I am struggling to model the thermal part for the low voltage circuit breakers based on IEC standards.
Based on the ...
0
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1answer
46 views
MCB with electronic trigger-off [closed]
How can I design a system that gives the functionality of an MCB (overload protection, operates in an AC circuit) with an electronic trigger-off.
So that once the device is in ON state, it should be ...
1
vote
1answer
107 views
Floating DC power supply (solar panels) - do I need double-pole breakers and why?
I am in the process of building a small off-grid solar setup.
There will be 4 parallel strings of panels in this setup, and I understand that for 3 or more strings, you need some sort of over-current ...
0
votes
1answer
55 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 ...
0
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1answer
70 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 ...
0
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3answers
107 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 ...
0
votes
3answers
248 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 ...
0
votes
3answers
889 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 ...
6
votes
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 ...
5
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4answers
4k 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 ...
1
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1answer
177 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 ...
0
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1answer
36 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 ...
0
votes
1answer
203 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 ...
1
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1answer
644 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 ...
1
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1answer
143 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 ...
1
vote
1answer
59 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) ...
0
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1answer
49 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 ...
1
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0answers
208 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 ...
2
votes
6answers
187 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 ...
1
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2answers
142 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 ...
0
votes
2answers
116 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 ...
0
votes
2answers
49 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 ...
1
vote
1answer
79 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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votes
1answer
61 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 ...
2
votes
1answer
544 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 ...
6
votes
2answers
840 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 ...
1
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3answers
410 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 ...
3
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2answers
1k 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
6k 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?
11
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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, ...
0
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1answer
195 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
votes
3answers
111 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 ...
0
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3answers
3k 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 ...
0
votes
4answers
218 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 ...
1
vote
2answers
357 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 ...
1
vote
1answer
137 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 ...
0
votes
1answer
585 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).
...
5
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6answers
16k 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 ...
0
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1answer
112 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 ...
1
vote
1answer
530 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 ...
0
votes
1answer
339 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 ...
0
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3answers
1k 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 ...
1
vote
6answers
4k 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 ...
