Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [circuit-breaker]

The tag has no usage guidance.

0
votes
1answer
43 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
votes
2answers
34 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 ...
1
vote
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
votes
1answer
44 views

MCB with electronic trigger-off [on hold]

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
66 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
44 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
votes
1answer
67 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
votes
3answers
85 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
108 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
518 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
votes
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
vote
1answer
128 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
votes
1answer
35 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
148 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
vote
1answer
182 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
vote
1answer
128 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
51 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
votes
1answer
48 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
vote
0answers
187 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 ...
3
votes
6answers
173 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
vote
2answers
125 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
87 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
47 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
78 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 ...
-2
votes
1answer
57 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
447 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
721 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
vote
3answers
403 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 ...
4
votes
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&...
0
votes
1answer
5k 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
votes
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
votes
1answer
178 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
92 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
votes
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 ...
0
votes
4answers
212 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
319 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
131 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
516 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
votes
6answers
15k 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
votes
1answer
105 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
441 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
328 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
votes
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 ...
-1
votes
1answer
382 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?
0
votes
2answers
571 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 ...
0
votes
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 ...
0
votes
1answer
97 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 ...
0
votes
1answer
255 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 ...