Would you say what is RCD, so a layman could understand

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MisterBill2

Joined Jan 23, 2018
13,824
So, is a. Kindof earthing. Is it not?
if proper earthing is given, you need not need rcd. Is it correct?
WRONG! "earthing" an item, only if it is done correctly, will prevent that item from supplying a shocking voltage, BUT it will assure that if some other item becomes charged that the earthed device will provide the connection to complete the shocking circuit.
The ground fault circuit interrupter would be connected in the mains power to whatever device is powered by the mains. If it is a 3-phase device with a three phase mains connection then a 3-phase ground fault device is required.
An RCD device that requires 30 milliamps to trip is not likely to provide much protection against any shock hazard, I believe that the ones I have installed will trip on less than 5 milliamps. But those are all installed at the outlets, which is a far better arrangement.
 

Ian0

Joined Aug 7, 2020
6,724
30mA is the most common rating, though 10mA is available from RS, but not the average electrical distributor.
Are RCBOs getting common in other countries? (Residual Current Breaker with Overload) It replaces a MCB in the consumer unit (fuse box) (and makes a mess of the neutral wiring in the box in the process)
30mA won't prevent a shock, but will prevent it from being fatal in most circumstances.
A RCD at the outlet won't protect the installation from failing insulation in the cables.
 

Ya’akov

Joined Jan 27, 2019
6,858
It's like the bird on the electric wire - if everything it can touch is the same potential, it's safe, even though it's all 6.6kV!
[/QUOTE
30mA is the most common rating, though 10mA is available from RS, but not the average electrical distributor.
Are RCBOs getting common in other countries? (Residual Current Breaker with Overload) It replaces a MCB in the consumer unit (fuse box) (and makes a mess of the neutral wiring in the box in the process)
30mA won't prevent a shock, but will prevent it from being fatal in most circumstances.
A RCD at the outlet won't protect the installation from failing insulation in the cables.
We are seeing combination AFCI/GFCI combination breakers in America. (Arc Fault Circuit Interrupter). AFCIs are now being required by code for certain circuits.
 

MisterBill2

Joined Jan 23, 2018
13,824
Given that at least in the USA the purpose of a GFCI is ONLY to prevent shock, having it at the outlet that a device is plugged into is by far the best choice, because, as mentioned in post #26, any branching in the circuit's neutral wiring will cause false tripping. THAT problem once cost me a day spent searching for the problem a few years back. For an RCI breaker to function correctly every bit of the connected wiring must be perfectly balanced, which is not a requirement for safe operation. Shared neutral wires can be totally safe and meet all code requirements but still trip an RCI breaker.
 

Thread Starter

jraju

Joined Jul 23, 2017
91
So, in short, normal switch drips in 16 a. whereas, rcd drips or tripss,which is correct, even at a current of 30ma for home, thus cutting the power for safety . Is it not.and also for looking cause for where it is wrong
please see my query about layman understanding of the concept.
is the rcd different for home ,shops, big companies
.
 

Ramussons

Joined May 3, 2013
1,321
A human is dead on electrocution whether in office or home.
The purpose of the RCD, or whatever you call it, is to trip the power supply if there is a Current imbalance. Stop.
 
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