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Questions tagged [circuit-breaker]

An automatically operated electrical switch designed to protect an electrical circuit.

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Arc fault receptacle or Arc fault breaker [closed]

When year did they start using the NTC in the ARC Fault breaker or AFCI receptacle?
Michael 's user avatar
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AFCI outlet AFCI GFCI breaker [closed]

What style NTC is being used in an AFCI outlet or AFCI breaker? I can’t locate it.
Michael 's user avatar
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Hook up 2 120 V AC battery backups to breaker box [closed]

I have 2 120 V AC VTOMAN 1800 battery backups. On my main breaker box, with an interlock installed, I want to turn off the main breaker and all dual poles (a/c and dryer), then through a 15 amp dual ...
John G's user avatar
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Needs help understanding this breaker: Chint NB1-63 C50. Confusing (63 or 50)

I'm trying to understand information on this AC breaker.(See picture) Is this Rated for 50 amps or 63 amps? Does the "C50" stand for Current? If you think it's 50 amps, how do you know this?...
RayLoveless's user avatar
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1 answer
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Where are the miniature molded case circuit breaker trip characteristics defined?

Some vendors specify a "trip-characteristic" for their miniature circuit breakers with a letter. B, C, K, Z specifically. From what I gather these seem to be standard designations possibly ...
martij7's user avatar
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Can I put ferrite cores around the romex in my electrical boxes and breaker panel? [closed]

I've recently replaced most of the breakers in my house with dual-function arc fault/ground fault protection. (I spent five years in forensics, I'm deeply paranoid, don't judge me.) Naturally I'm ...
Stephen Collings's user avatar
1 vote
3 answers
237 views

Do I need a resistor in circuit when charging capacitors?

I want to charge a group of capacitors whose total equivalent capacitance is \$ 705 \:\mu F\$ and whose equivalent series resistance is on the order of \$10^{-2} \:\Omega\$. I am trying to charge them ...
toomanyfeet's user avatar
3 votes
1 answer
464 views

Electronically activated circuit breaker

I want to be able to disconnect the load from a circuit, which may be of variable amperage, possibly up in the hundreds. I guess what a normal person would do is probably use a contactor of some sort. ...
php_nub_qq's user avatar
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Minimum wire size for a 32Amp breaker

Problem statement: Sailing boat with a 16A onboard breaker need to connect to a 32A onshore power supply. What is the minimum cable size from the onshore 32A breaker to the onboard 16A breaker. Under ...
CaptainMJ's user avatar
3 votes
4 answers
1k views

What is the purpose of neutral disconnect in a circuit breaker?

I saw some circuit breakers that have a separate neutral disconnect. For example: What is that for? When do you need to disconnect the phases only? Why not use a circuit breaker that always cuts all (...
Carlos Garcia's user avatar
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How to detect which breaker has tripped?

I want to test how long it takes for four breakers in series to trip. I want to be able to identify which breaker first tripped. I came up with this circuit. S1 to S4 are the breakers. Only S1 is ...
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Sizing capacity of a 1-phase breaker to feed a VFD and a 3-phase motor

I have a 3 phase 2HP motor that draws 5.8Amps at 240v I want to feed it with a VFD with the following specs: VFD rated power: 4kW 1-phase input: 36 Amps 3-phase output: 18.5 Amps The VFD is of ...
Max L.'s user avatar
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How is AFCI Powered?

With arc-fault circuit interrupters once there is overcurrent or arcs what is powering the electronics inside the AFCI that are doing the signal analysis? Won't the electronics get damaged if it's ...
Justin's user avatar
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1 answer
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Rating of circuit breaker for protection

This circuit breaker is rated as 12V-48V 100A and I have to use this circuit breaker between additional alternator (24V 100A) in my vehicle and additional battery bank to provide overcurrent/short ...
James Ross's user avatar
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1 answer
193 views

Identify this RCD or RCBO

Here's a close up as requested. Apologies for it being a bit fuzzy. Is there any reason why this shouldn't be used to protect a dedicated 4mm TPS circuit for a 3kW spa pool? Thanks for your help. Can ...
Bob's user avatar
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Calculation of thermal equivalent short-time current

Regarding checking the thermal resistance of switchgear "Ith", To make the comparison, one can compare the permanent short-circuit current "Ik" calculated by the ETAP software and ...
zazar's user avatar
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-1 votes
1 answer
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Can I add a 20A breaker to this electrical panel [closed]

I replaced the oven at my small condo (600 sqft). Oven is 2300 watts/ 9.5 A. It needs a 20A breaker. The panel has a few empty slots. Question: What's the best way to confirm that the panel can handle ...
SamuraiJack's user avatar
2 votes
0 answers
57 views

Break logic signal irreversible [closed]

I have a PCB which needs a 3,3V logic signal during the start-up of a system. Then this signal needs to be irreversibly broken. Of course this could be done by flipping a switch, but the PCB isn't ...
bthunder's user avatar
1 vote
0 answers
178 views

Do power strips need to have a breaker?

In North America we commonly use power strips to connect equipment to the building. https://en.wikipedia.org/wiki/Power_strip I noticed that some power strips have a circuit breaker, and some do not. ...
BetterSense's user avatar
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2 answers
147 views

Circuit Protection: on-board vs off-board; manual vs auto. Which is better for our application?

RE: Circuit protection for small health & beauty product (for mass-production) similar to a foot spa whereby a portion of the user's body will come into direct contact with 1.5 gallons of water ...
tayglo's user avatar
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1 answer
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Why do 3-phase selective circuit breakers appear as separate (not joined) ones?

I'm looking at 3-phase selective circuit breakers like this: Unlike a typical 3-phase circuit breaker, this selective breaker appears to be essentially 3 separate breakers all put together. Strangely ...
Dmitri Nesteruk's user avatar
1 vote
2 answers
107 views

How to power third pin "neon lamp" on thermal breaker switch C1005B?

I'm using a C1005B 10A illuminated breaker switch to toggle 120VAC by breaking the hot wire. The switch has three pins Neon lamp Load SW line Should pin 1 be attached to the load or SW line?
earl's user avatar
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How to design a transformer that can inject 350A for 1-2 sec - for testing short circuit tripping of 32A type C MCBs

I am trying to design a transformer that can be used for field testing of MCBs up to 32 A (Type C). The testing (for short circuit tripping of The MCB) will require maximum about 350 A to be injected ...
Jitendra Mahapatra's user avatar
4 votes
3 answers
837 views

Caravan park with 3 phase power supply, our B phase amps are overloading and tripping the circuit breaker [closed]

We have had the phases balanced, and the problem is still occurring. We initially added a 60 kVA generator taking out our amenities block, and this helped during peak power times of day. It is no ...
Alva Beach Tourist Park's user avatar
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1 answer
156 views

Induction cooktop tripping breaker (the IGBT was just repaced) [closed]

I have replaced the burned IGBT + added a new thermal paste, and it worked fine for about 10 minutes on the lower power setting, but when I turned it up to max it failed after a few seconds. I haven't ...
Tomáš Pilný's user avatar
0 votes
2 answers
75 views

Does a control panel that will start/stop two pumps require its own circuit protection?

Does a control panel used to start/stop two pumps require circuit protection for the main 208V feeder lines if those lines are already protected at the main panel in a separate room? The main panel ...
voltron's user avatar
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1 vote
1 answer
88 views

240Vac circuit breaker on 110Vac circuit [closed]

I'm wiring up a 110Vac circuit, and for various reasons I'd like to use a specific breaker. This breaker is rated for 240Vac circuits. Is it ok to use it for 110Vac circuits? It mentions that the 2 ...
BeB00's user avatar
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Circuit breaker trips, but it shouldn't

I built very simple circuit which allows turning on/off using microcontroller low voltage signal. To have it protected I've decided to add circuit breaker. Since it consumes 120W of power (around 0.5A ...
seeker's user avatar
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Can someone help me understand how the circuit breaker will operate in this scenario?

For some reason I can't wrap my head around how inverse time overcurrent relays work. Here are some trip currents and times from this curve for the Schneider Electric, Square D, QO 15A miniature ...
xrosaber's user avatar
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5 answers
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Avoiding breaker trips with a heater and PWM signal

I am controlling a 1500W heater with an SSR at 5Hz. The heater's voltage is 110V freq is 60Hz and my breaker is rated for 15A. I have other loads on this circuit consuming about 2A. This means the ...
Feynman137's user avatar
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3 votes
3 answers
414 views

Why are switchgears rated in specific capacities such as 63A, 100A, 125A and so on?

I am working in a consultant industry, wherein we get the switchgears from different OEMs. I wonder why the switchgears (including fuses and fuse-gears) and control gear assemblies are rated in the ...
DaSnipeKid's user avatar
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74 views

Non-isolated DC/DC converter safety question

If I were to have a 350VDC or similar bus voltage, protected by solid state switches meaning near instantaenous shut-down, what would the safety implications be if I were to use to step down this ...
Brandon Kellett's user avatar
1 vote
3 answers
531 views

DIN rail-mount on/off switch or toggle button

I want to manually flip a switch to connect and disconnect a 10 μF capacitor from my microcontroller's reset pin in my industrial application where everything is mounted on DIN rails. The cap is ...
AnalogDigital's user avatar
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1 answer
95 views

Why do we need total selectivity?

If a fault happens in DR3 that makes Ideltan bigger than 30mA, the flow of current will stop. What's the need for the other circuit breakers?
Scipio's user avatar
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1 vote
2 answers
227 views

Persons protection: residual-current circuit breaker for DC?

I'm currently reviewing the schematics of the power supply of a robot prototype. The 380 V AC (3 phase) is converted (isolated converter) into 320 V DC (up to 20 A). There are only 3 wires going to ...
Sandro's user avatar
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1 vote
1 answer
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Why line current is increasing when electrical devices are powered on using circuit breakers instead of normal switch?

My connection was very simple. Just a PLC with no load. It draws very little current. Usually, while working, I keep on the Over Current Protection mode. No problem happens if I turn on or off the PLC ...
Sadat Rafi's user avatar
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0 answers
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Branch circuit breaker ineffective at preventing mains trip [closed]

At my place of work, we occasionally deal with appliances which have faulty grounding resulting in an earth leakage trip. Some of these faulty devices have also been tripping the MCB, probably due to ...
Benjamin Tse's user avatar
5 votes
2 answers
1k views

Are there breakers which can be triggered by an external signal and have to be reset by hand?

Essentially, I would like to connect a breaker to a smoke detector and have it trigger when it activates. Are there any breakers that can be triggered by a separate external signal and which have to ...
Reewen's user avatar
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Is there any kind of “motor current/load limit curve”, like the one for wires?

When we try to select a motor protective circuit breaker (for an IEC induction motor), we can compare its tripping curve to the motor’s time-current curve during starting and steady-state. To avoid ...
LoukasGr's user avatar
0 votes
3 answers
1k views

What happens to a circuit breaker at overvoltage condition?

Circuit breakers are used for overcurrent / short-circuit protection. At overvoltage conditions, what will happen to the circuit breaker if the line current stays within the rated current? For example,...
Sadat Rafi's user avatar
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When a short circuit happens in one circuit of a DB, the main ELCB of 10 DBs trip simultaneously

A total of 31 distribution boxes (DBs) are available. The earth-leakage circuit breakers (ELCBs) of 10 DBs trip simultaneously when a short circuit happens in one circuit of a DB. Why does this happen?...
Ajas 's user avatar
-1 votes
2 answers
239 views

What size DC circuit breaker to buy for a 12 V, 80 W solar panel?

I have bought a 12 V, 80 W solar panel and before I start using it I want to install circuit breakers between the solar panel and the charge controller, the charge controller and the battery, and the ...
Ash's user avatar
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0 votes
1 answer
145 views

Voltage drop when ship's load is connected to substation shore panel

I am facing a significant voltage drop (for every 3 kW of load there is a drop of approximately 1 V) when the ship's shore supply is connected to the yard shore supply's distribution panel. The yard ...
Anil Meena's user avatar
0 votes
1 answer
127 views

Circuit breaker pops when flipping switch

The circuit powers an LED light. Using a multi meter connected to the two screws which hold down the white and black cables, the switch reads as "OL" or as "_/__" when checking for ...
TeckFudge's user avatar
2 votes
2 answers
353 views

Meaning of 3P+N/2 in circuit breaker

In the following selection table of Legrand DPX3 three phase molded circuit breakers (Legrand 422000 to 422013) along with the familiar 3P and 4P circuit breakers, there are 3P+N/2 circuit breakers (...
Brethlosze's user avatar
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1 vote
1 answer
232 views

Should I use DC-specific circuit breakers?

I’m building household electrical distribution boards where the LED lighting controllers take 24V. To this end I am using a DIN rail-mounted 220-to-24V converter. I connect this converter to ...
Dmitri Nesteruk's user avatar
-1 votes
1 answer
411 views

How to test an MCCB for safe functionality? [closed]

Ive got a few MCCBs for an old system, what is a suitable way to test them to make sure that they function correctly and safely?
user27511's user avatar
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3 answers
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Safety of a polarized DC breaker between the battery and the inverter

DC breakers use a magnet to blow the arc into the quenching channel. If the current is flowing in the wrong directly, the arc is pulled into the guts of the breaker and can cause the arc to be ...
Sampath Liyanage's user avatar
0 votes
1 answer
119 views

Safety check - Is this Amazon PV combiner box labeled wrong? 15A Vs 32A - 500V vs 1000V

I'm currently working on a solar circuit. I wanted to protect my internal systems from my panels in the event of a surge. I purchased a PV combiner box from Amazon - link to product. It claims to be a ...
Bms85smb's user avatar
  • 211
0 votes
1 answer
119 views

Single vs two pole breakers - Single phase loads on IT power with distributed neutral

Are two-pole breakers required on single-phase 230 V loads when connected to a 3-phase supply with IT earthing system (with distributed neutral) in Germany? Where in the standards is this requirement ...
Mike Jones's user avatar