Questions tagged [circuit-breaker]
An automatically operated electrical switch designed to protect an electrical circuit.
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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 ...
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Why is the floor corridor circuit breaker tripping before my flat one? [migrated]
This is not as much about a circuit as it is about my home electrical installation. That said, I have seen other questions on the subject so I hope I'm not off-topic.
I have a situation in which the ...
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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 ...
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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 ...
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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 ...
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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 ...
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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.
...
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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 ...
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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 ...
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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?
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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 ...
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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 ...
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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 ...
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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 ...
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CT Standards for HV Breakers (145 kV) - Siemens
I (young, new engineer) am researching the standard CT ratio for a Siemens HV circuit breaker for my senior engineer. He tells me they don't post their standards like other companies do and I am ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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?
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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,...
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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?...
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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 ...
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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 ...
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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 ...
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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 (...
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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 ...
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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?
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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 ...
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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 ...
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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 ...
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How exactly does a breaker finder work?
I've used a breaker finder for a while now, and I'm curious as to how it actually works. The only explanations I can find online are layman explanations (e.g. it sends a signal up from the outlet to ...
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Why do Americans use fuses and not differentials and breakers like Europeans do?
I recently moved to North America, and I was wondering why the houses here seem to be protected by fuses rather than breakers and differential switches like we have in France for example.
It would ...
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Can a lower gauge jumper be connected to a high amperage circuit as long as it is going to an appropriate sized breaker?
The 14 AWG wire is connected to an appropriate sized circuit breaker to prevent that run of wire from drawing too many amps; however, my concerns would be that the 2/0 cable being in such close ...
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Breaker with alarm
I am thinking about a theft alarm for an HVAC condenser. The condenser is installed outside and subject to burglary. I think a viable approach is detecting when it is detached from power.
The HVAC ...
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Charging capacitor trips breaker
I am designing a circuit to drive a DC motor from rectified mains voltage. For that, I have added a 1200uF capacitor. My problem is that this circuit is supposed to work on a user's home power plug, ...
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Three-phase circuit breaker trip current
If a three-phase circuit breaker is specified as, for example, a 32 A breaker, does this mean the breaker will trip when the current in a single phase exceeds 32 A, or when the total current of all ...
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What will happen if I use RCBO where there is no neutral in the system?
I need some help. Could you please go through the scenario and try to answer my query below?
This system is installed in a ship where there is no neutral connection available.
A 440V/220V step-down ...
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3 Phase breaker - Current Limit
I have a simple question... If I have this 3 Phase breaker:
That means its current limit is 20A right? My question is, is it limit for the whole breaker or limit for every phase separately?... What ...
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16 A mains breaker and heat
So I got curious and could not find any good information on high breaker load over an extended period.
In my home (in EU, 240V) there is a breaker which is rated for 16 A. If 16 A is drawn for hours ...
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The home single phase differential switch cuts whatever I did [closed]
I have a 30 mA sensitivity differential switch which cuts each time I lift the power switch even if the circuit breakers for the sockets and the lighting are off (even if all the circuit breakers on ...
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CBE Schematic and Wiring
I'm in the process of installing a circuit breaker between a power supply and an HMI device, but have some uncertainty when it comes to illuminating the rocker switch.
The part number is TA35-...
