Questions tagged [rcd]

Residual Current Device (RCD), Residual-Current Circuit Breaker (RCCB), Ground Fault Circuit Interrupter (GFCI), Ground Fault Interrupter (GFI), or an Appliance Leakage Current Interrupter (ALCI). The exact wording of the term varies from country to country.

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RCD testing using a plugin tester in an outlet without ground [closed]

I have a plugin tester which tests different electrical faults such as open ground, swaps etc. There is also an RCD test button. I put this in an outlet where there is no ground, only neutral and live ...
mindentropy's user avatar
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1 answer
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RCD trip when current flow from Live to Earth [closed]

Can an RCD detect current flowing from live to earth assuming neutral is disconnected (or someone improperly connected earth to neutral terminal and nothing to the earth terminal)? From what I have ...
mindentropy's user avatar
3 votes
1 answer
373 views

Neutral to ground bonding place question

Does the neutral-ground bonding need to be done before the RCD/GFCI breaker? If there is an energized metal frame due to a fault, will the RCD/GFCI breaker see a difference between live and neutral ...
jmann's user avatar
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2 votes
3 answers
275 views

What happens when you get a fault to earth without an MEN link on a 3 phase generator? [closed]

For context, an isolated type single phase generator (no earth stake or neutral-earth link) had a residual current device connected to it and then a fault between active and earth was placed on the ...
SS1's user avatar
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1 answer
353 views

Does the RCD go before or after the MCB?

I am going to connect a 4 pole RCD and MCB to the input of a power supply. Which one should I connect first, the RCD or the MCB? I have seen them connected both ways.
pepopi1's user avatar
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2 votes
1 answer
145 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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1 answer
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Voltage Earth Leakage Module wiring

This is an old 4x125 A, 0.03-3 A Adjustable Earth Leakage Module (EL), 26013 DPX 125 Legrand, fitted aside a 3x125 A Moulded Case Circuit Breaker (MCCB), 25041 DPX 125 Legrand. It was installed as a ...
Brethlosze's user avatar
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3 votes
2 answers
1k views

Inverter causing RCD to trip

I have an offgrid inverter/charger - an MPPSolar PIP4048MS (4000W inverter, 48V system). By and large it has worked well for 7 years. Recently I bought an MPPSolar PIP5048MS (5000W inverter, 48V ...
user1273784's user avatar
-10 votes
1 answer
303 views

Using an RCD with an isolation transformer for an electrical pig stunner [closed]

Someone asked me to build an electrical pig stunner. I will make it simple as in the schematic attached. Even I'll put an isolation transformer I would like to take extra safety measures and place and ...
k1gabi's user avatar
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1 answer
385 views

Can an RCD detect a fault on an isolated circuit?

I was installing a new plug socket today in an outbuilding of my house, which is wired up to a small circuit breaker box which houses breakers for the lights and plug sockets in this outbuilding. This ...
S.Stevens's user avatar
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Differential current sensor probe- Ground leakage current measurement probe for oscilloscope

I would like to know what you use to measure differential current which is also leakage current sensing. Background: In industry , the AC or DC current flowing from inverter/ converter needs to have ...
Power_Electronics's user avatar
2 votes
1 answer
381 views

Is it OK to use a 2 pole RCD on each Line of an unbalanced 3 phase installation

I have a building that is mains supplied, but has a 3 phase back up generator-- black outs are almost daily here. There is no 3 phase equipment in use. The current instillation is about 12kva, but ...
SV Savannah's user avatar
1 vote
4 answers
326 views

Why can a raclette grill with over 400kOhm resistance between phase and null against earth trigger a 30mA RCD in a 230VAC network?

I have a 1.2kW 230V~1AC raclette grill which triggers 30mA RCDs, probably when the bi-metal temperature controller turns it off. Not to repair, but to get better in failure mode understanding and root-...
Torsten Knodt's user avatar
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2 answers
108 views

Can an RCD do the job of an ordinary fuse?

Suppose we have a short circuit somewhere in a house. Does a residual-current device (RCD) stop the current in this situation exactly as an ordinary fuse does? or it's not reliable for this?
apadana's user avatar
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1 answer
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Investigating RCD nuisance tripping when ACCL changes power source

My apartment is supplied with 2 sources of electricity: the grid and a generator in the apartments premises. The change over is controlled by an ACCL. The apartment has an 25A ELCB/RCCB with 100mA ...
Nikhil's user avatar
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4 answers
357 views

Will a 30 mA RCCB trip if the differential current is less than 30 mA?

All available literature states that an RCD trips whenever there is imbalance between the currents flowing through the Live and Neutral wires. But does it need to be higher than the labelled value?
Nabin's user avatar
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2 votes
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How to check if Neutral is grounded properly?

I was thinking of buying a Residual current device but I don't know if the power supply to my home is grounded properly or not. For initial testing I used my multimeter to check the voltage coming to ...
Hemant Yadav's user avatar
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1 answer
108 views

Does this PRCD have any differential current transformer inside?

Its very important to have portable residual current devices (PRCD) to plug in our electrical equipments in the field, or use anywhere or even in our workplace. I got this china made PRCD from a ...
Jtl's user avatar
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1 vote
1 answer
107 views

Why is there a fuse in this RCCB (RCD)?

I supposed there is a sense coil inside the RCCB (RCD)of this tankless water heater. But why is there a fuse inside one of the load side to the circuit? Isn't the round circle the sense coil where the ...
Jtl's user avatar
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2 answers
211 views

Is there a current sense coil inside this ELCB?

Is there a current differential sense coil inside this ELCB (Earth Leakage Circuit Breaker) just like GFCI or RCD? I took it from a unit and I dont want to break it apart to peek I cant find any ...
Jtl's user avatar
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RCD "Clamp/Snubber"

I am attempting to figure out this "RCD Snubber" as seen below: The Eval Sheet says "The resistor capacitor diode (RCD) snubber for the two synchronous rectifiers consists of R3, C29, and D4 for one ...
Carlo's user avatar
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1 vote
2 answers
211 views

Selecting residual current for RCBO

I'm creating a portable test socket for electrical appliances that comes equip with a RCBO, power meter and possibly emergency stop button. My test socket will operate at max 240V AC and 10A. The ...
Max's user avatar
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1 answer
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Avoiding RCD tripping with Inverter Drive

I have a single-phase inverter drive hooked up to an RCD supply, which keeps tripping when powered. Removing the RCD is not an option, so I'm looking into other ways to make this work. Although ...
19172281's user avatar
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0 votes
2 answers
188 views

Connecting two RCD's serially [closed]

I want to make a electric leakage protection circuit for a water heater in case of heater gets corrupted in time. We use rezistance 220V - 1500 watt. We grounded the water (because rezistance have ...
harold.potter's user avatar
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1 answer
2k views

Testing an RCD switch by short circuiting neutral and ground

This question has some implications on home related work with mains. Never take what you read on the internet as the truth when lives might be in the line. That is how I'll be treating potential ...
TheMeaningfulEngineer's user avatar
1 vote
2 answers
1k views

RCD Live and Neutral Protection

I understand that an RCD device helps to provide protection against electric shocks when completing a circuit between Live and Earth wires, where the Neutral and Earth wires are separated before being ...
Algebrator's user avatar
1 vote
4 answers
769 views

Trip RCD with a circuit

I am wondering if it is possible to trip an RCD safely with a custom circuit. I know the RCD detects current leaking to ground, so could a relay and a resistor be used to short the active to ground? I ...
jdm's user avatar
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0 votes
2 answers
2k views

How do 100mA ELCBs provide human protection?

Usually we use 30mA rated ELCBs in our homes. This is for our own protection against leakage current. But in instances where you have a 100mA or 250mA 3 pole ELCB used in industry, an earth leakage of ...
Ph3ng's user avatar
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1 answer
1k views

Do RCDs work for DC systems?

I'm designing a product powered by an alternator with a DC regulator that will provide me with 24 V DC and something like 100 A rated consumption. Do RCDs protects against earth leakage current in DC ...
Nicolas Cavalieri's user avatar
-1 votes
1 answer
213 views

Will RCDs function properly in the Philippines?

In the Philippines the two pin plug can go into power socket either way. Most domestic wirings have an earth at the power pole. My question is can an RCD be installed and function 100 % in ...
David McLintock's user avatar
1 vote
1 answer
1k views

How do RCD Testers work?

RCD-Testers can be used to check if the residual current device (RCD) of the installation is properly working. How to they do this? I want to build my own RCD-tester. Which circuit can be used to ...
Michael Haar's user avatar
1 vote
2 answers
3k views

Why so many specs for RCD vs US GFCI (or RCDs?)

Why are there so many RCD (Residual Current Device) specs and mA tripping thresholds for use in equipments in Europe vs the USA where they were not used (but only 5mA GFCI for personal safety)? Don't ...
Jtl's user avatar
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1 vote
1 answer
4k views

Using a residual current device when there is an isolation transformer

In a system, currently there is no circuit breaker and RCD, but there is an isolation transformer as in the diagram below: simulate this circuit – Schematic created using CircuitLab As you see ...
user1999's user avatar
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0 votes
2 answers
204 views

RCD tripped when measuring with a scope

Below was my setup: The moment I connected the probe the RCD tripped. My scope was earth grounded. Does that mean I shorted the neutral and the earth ground? I know that neutral and earth are ...
user16307's user avatar
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2 votes
2 answers
2k views

Automatic Self-Test Circuit in GFCI outlet

What kind of self-test circuits or method do they used in the GFCI outlets generally? Is it just firmware or is there a physical addition (and what it is usually?) This is because after 2015, it is ...
Samzun's user avatar
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0 votes
1 answer
101 views

Basic 3 phase question

I've come across this question at work and it has stumped me... even though it is quite basic. A distribution board is supplied by 3 phase 415 AC power. From the distribution board to a circuit ...
Liz_eE's user avatar
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11 votes
3 answers
2k 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, ...
Natthapol Vanasrivilai's user avatar
2 votes
4 answers
251 views

Why do RCDs / GFCIs sense differentially rather than directly?

As far as I know, all RCDs / GFCIs sense leakage current by differential measurement between active and neutral with a current transformer. Both the active and neutral wires will pass through the ...
user avatar
1 vote
2 answers
912 views

Confusion with RCD principle of operation

I understand that an RCD is a device that interrupts an ac circuit (usually in outlets) if current between live and neutral/ground is not the same, indicating something is wrong with the circuit. It ...
Murey Tasroc's user avatar
1 vote
2 answers
247 views

Transformer Question - Two Output of Different Voltage

I'm fairly new to electronics, but still have a basic understanding (1st year Electrical Engineering Student). I've started a project of repurposing a used treadmill I found online for $20 as a ...
James's user avatar
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0 votes
2 answers
119 views

Residual-current device: Would a big coil trigger it because it stores electrons? [closed]

Imagine a residual-current device at your home - basically it counts influx of electrons vs outflux of electrons. If there is a missmatch (e.g. I=30mA over t=30ms), it triggers and disables the ...
venti's user avatar
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0 votes
1 answer
794 views

How to wire a RCBO/GFCI correctly (in series with the upstream RCBO/GFCI)?

For one of my projects, I need to add a RCBO/GFCI for the protection of the users. I know that there is a RCBO somewhere up the chain, therefore I am facing a confusion: there is a non-zero resistance ...
Mister Mystère's user avatar
0 votes
2 answers
168 views

How does a GFCI breaker protect me if my device has no connection to ground? [closed]

I use a hairdryer with a 2-prong US plug (no ground). Suppose I plug it into a GFCI-protected outlet and drop it into a sink full of water. Will the GFCI still trip even though my hairdryer doesn't ...
Jeffrey Bosboom's user avatar