Difference Between Elcb And Mcb Pdf Reader

Moving soon to a smaller apartment with very little storage space we went through a lot of things that we had to get rid of. A rule of thumb was: if we didn’t use the item during the past 12 months it had to go well, not really, and certainly not for my electronic stuff, but this was the general idea! During this exercise we came across a small table grill. It looked like almost new and we didn’t remember using it a single time during the past three years while we were living in this house. Probably we just forgot about it, having an outdoor barbeque. This is what happens when you have too much storage space Objects get put aside and forgotten about!

This one definitely qualified for the “has to go” category. Before deciding what to do with this appliance I resolved to test it, thus I inserted the power plug into the wall socket.

The grill started heating then, after a few seconds, the house circuit breaker tripped off. Ah, this started to be more interesting! The quiet way the circuit breaker when off, without any spark or other kind of typical “short circuit bang”, let me think that the cause was an earth leakage. I took the appliance up to the workbench for investigation.

Enclosed Circuit Breaker (ECB) with. Arcflash Reduction. Summary of Differences Between Low Voltage Power Circuit Breakers. Insulated-Case Circuit. UL 1066—LVPCB. Molded-case circuit breakers and insulated-case circuit breakers typically comply with the following standards: □ UL 489—MCCB. Feb 18, 2014. The earthed connection was used to detect any voltage difference between the earth and neutral indicating that there was a current flow into the earth being monitored. If the fault current. Normally the RCCB would be used in conjunction with overload protection such as a Miniature Circuit Breaker (MCB).

The first measurement, using a digital meter between Live and Neutral of the power plug, indicated a resistance of 36 Ohms. This could be considered as normal for a powerful appliance (1600 W / 240 V). Next step, measuring between Live and Earth, the digital meter was showing inconsistent and unstable readings. It was time to switch to the analog meter. This was one of those situations where the analog meter is much better.

An insulation leakage is not a linear load and its value will depends on the current passing through. The analog Ohmmeter supplies more current to the device under test than the digital meter, so we have a better chance to get some reading. The meter displayed a stable value of around 50 kΩ, which indicated an insulation leakage and explained why the circuit breaker tripped off The insulation resistance must show infinite under any scale of the analog meter. I could also have done an insulation test but the present measurement was enough to highlight the problem. Let’s remind how this works. A typical household circuit breaker has two functions: a) to interrupt the circuit if the line current goes beyond a certain value and b) to interrupt the circuit if there is an Earth leakage current. Those devices are called Residual Current Circuit Breakers (RCCB) or Earth Leakage Circuit Breaker (ELCB).

The figure below shows one of the RCCB installed in our house. It is labeled 40A and 0.030A. It means that it will trip off if the current is higher than 40A (3 phases) or if the leakage to Earth is higher than 30mA! In a house or apartment the Neutral is usually connected to the Earth in the entrance switchboard.

From there, three separated lines are fed to the power points. Each piece of equipment will be connected to the Phase (Live) and Neutral.

The frame or cabinet will be connected to the Earth as seen below. When there is no fault the current flowing from the Phase line will be the same as the current returning through the Neutral. There is no current flowing through the Earth wire.

In case of a fault, part of the Phase current will return through the Earth line instead of the Neutral line. The current returning through the Neutral will no longer be equal to the current flowing from the Phase: The RCCB measures the current difference between the Phase and Neutral wires. If the difference is more than 30 mA (for most countries) the circuit breaker trips off. The following picture shows the operations principle of a RCCB: The hart of the device is a magnetic core with three windings. The supply current will create a magnetic flux into the core. The return current (through Neutral wire) will also create a magnetic flux but in the opposite direction. If both currents are equals, those two magnetic fluxes cancel each other.

In case of a fault, both fluxes do not fully cancel each other. There will be a residual magnetic flux which will induce a current into the third winding.

Remember we are talking about AC, it acts like a transformer. This current energizes the relay to trip off the circuit breaker. Pressing the test button also will create a current imbalance, hence trip off the device. If the equipment cabinet is not connected to the Earth (broken wire or dodgy installation) the leakage current might flow to the Earth through someone touching the cabinet. A current of around 30 mA (0.030 Amps) is considered potentially sufficient to cause serious harm or a cardiac arrest if it stays for more than a fraction of a second.

RCCBs are designed to disconnect the conducting wires fast enough to prevent serious injuries from electric shocks. Back to our grill, we could suspect that the leakage was inside the heating element. To be sure, let’s open the appliance and disconnect the heating element: As we can see there is not much in it and it is easy to disconnect the heating element and measure it. As expected the results were the same as measured directly from the power plug. So the heating element is definitely faulty. As the grill is like new but have not been used for more than 3 years I suspected that the problem could have been caused by moisture entering the element. Can it be fixed?

I wondered if, by heating the element, we might get rid of the moisture but I wanted to be sure so I did a search on the Internet. Sure enough I found a site where someone restored a coffee machine heating element by heating it on a gas flame. And it worked From there, I imagined that I could heat the element by running the grill during a few minutes after temporarily disconnecting the Earth wire (green/yellow in the picture) so the RCCB would not trip off. This can be dangerous and one must be very careful not touching any part of the equipment while doing so. But here we go, for two minutes only: After a couple of minutes unplug and let it cooling down, reconnect the Earth wire, put everything back together and measure again. Bingo, the Live to Earth resistance went up to around 500 kΩ. This was still not good enough but it was a conclusive improvement.

So I decided to give it more time. If it took several years for the moisture to get in we cannot expect it to get out within a few minutes only. So I let it rest for a day (switched off of course)!

On the following day the resistance had risen to over 1 MΩ. One more resting day and it barely moved the pointer of the multi-meter on the x10K scale. At this point it was possible to run the grill, Earth connected, without having the RCCB tripping off. Then I performed an insulation test that shows 1340V.

Was the problem fixed and will it return? Time will tell us. It probably depends on how often the ones who will inherit the grill will use it and where the appliance will be stored. Gerald Musy, Penang- Malaysia Please give a support by clicking on the social buttons below. Your feedback on the post is welcome. Please leave it in the comments. P.S- If you enjoyed reading this, to subscribe to my blog (free subscription).

That way, you’ll never miss a post. You can also forward this website link to your friends and colleagues-thanks! You may check out his previous article below. Hi Robert, Thanks for your comment.

Indeed this instrument is a transistor tester. It has a reverse breakdown voltage function that we can use as insulation tester up to 1500V. I use it time to time to test Zener diodes. As you know the reverse breakdown voltage of a Zener diode is the Zener voltage itself. As they are very hard to read, often too small, I can find out the value this way. It can also be used to test capacitors breakdown voltages. Be careful to discharge the capacitor after this test.

I was bitten a few times 🙂 Cheers, Gerald. Great story Gerald. It reminded me of a fix that my father told me about when he was the service manager at a major appliance manufacturer. Apparently even normal stove and oven elements sometimes do not work properly and end up with a lower than expected resistance. I am not sure what the symptoms were but I expect that they blew fuses or tripped the breakers since they would draw too much current when turned on. The ELCB would not be a problem since built-in stoves do not pass through an ELCB by default and I believe he was doing this before ELCBs, RCDs and Safety Switches became the normal thing to use.

His solution was a little safer in that you could remove the element causing the trouble and just place it in the oven to heat it externally. After cooling the element would often be restored to a functional state. I learned a lot from my father. He will be pleased to know that things haven't changed much in the repairing world. Best wishes to all. This article has information that is wrong and unsafe: 'It means that it will trip off if the current is higher than 40A (3 phases)'.

RCCB/ELCB/GFI can only protect against current leakage, and does NOT have the component to protect against overload/overcurrent. The 40A is the rating that the RCCB can safely operate in. Use a load greater than 40A on this RCCB, and it will simply overheat and melt. The RCCB will NOT trip. MCB is the breaker that protect against overload/overcurrent. The 40A overload rating on a MCB is simply a nominal rating, does NOT mean it will always trip at above 40A. The overload component is thermally triggered with respect to time, which is another rating on the MCB (whether it is Type B/C/D curve).

The 6/10/15kA overcurrent rating on a MCB is magnetically triggered for protection against short circuit. RCBO is the device that can protect against BOTH current leakage AND overload. Very nice article. Download Detective Conan 692 Sub Indo Mp4. I recently had a an experience with a spa heater and would like to share, because in many ways it was similar but also a very different and potentially dangerous situation. We have one of those Bestway Lay-x-spa inflatable hot tubs that are popular in the UK.

We're in the US so it goes here by Coleman. This is the kind with the 'egg' that contains the pump, bubbler, controller, and heater. We had a big and sudden thunderstorm, during which the unit was mistakenly left on and the GFCI breaker on the plug tripped. After the storm, the unit tripped the breaker constantly. Tests indicated it was only tripping when the heater was turned on.

I have some experience with electrics, so my son and I resolved to disassemble it and see if we could find the problem. Inside the unit there is a ceramic heater embedded in an aluminum tube that doubles as both water pipe and heat sink. The heater contains two elements which are comparatively compared to grill or space heater elements. Unlike your grill, the unit has electronic controls, so we can't simply test resistance at the plug. We took the heater block out and tested both elements with a multi-meter. After figuring out that our first digital multi-meter might be faulty, we were able to test them both at between 80 to 90 Ohms each. To me this seemed a bit low, as tear down videos on YouTube showed other people getting about 250 ohms resistance.

Having some experience with heaters and doing basic research I suspected current may be leaking from the elements and tripping the GFCI. Finding that replacements parts would have to be purchased on the secondary market and imported from UK (on the slow boat), we talked about running the unit disconnected ground, or un-wiring one of the two elements as possible options.

All of these options are a bit risky. The nature of water heaters makes it basically impossible to do tests without the unit connected to water and the pump running.

Playing with water and electricity should not be taken lightly - even by experts. We resolved to err on the side of caution and do as many tests as possible. We put the unit back together in its original configuration and connected it to the spa. We were surprised and delighted to see that now the unit magically stayed on with the heater running - at least for a time. My guess was that the work we did gave some moisture in the heater time to evaporate, or that possibly the GFCI itself had become oversensitive.

Being frustrated that the unit was now working better but still not long enough to heat the pool, we opened it up and disconnected the ground lead only from the heater block itself. The rest of the unit is still grounded. In this configuration the heater runs for hours without tripping the GFCI. This makes me believe the issue is only with current leakage like your grill and not the GFCI plug itself, though the plug does get warmer than I'd expect. Now of course, chlorinated water is an excellent conductor, and the pump is pushing water right through the aluminum block which is leaking current, so we're keeping the cover on the unit and everyone is warned to stay well away. It cannot safely stay in this configuration forever.

The idea here is similar to yours, that running the heater a while and letting it get hot should 'cook' any moisture out of it. We can't put the unit in the over and heat it externally without risk of melting the wire insulation, so that's out.

Ultimately, will it work or not work, who can say at this point. I guess we'll know in a day or two. Cricket Scoring Program For Mac. Needless to say nobody will be jumping in the tub while the ground is disconnected. As we wait for a replacement part to travel halfway around the world, it also makes sense to drop into the local hardware store and purchase a replacement GFCI plug for under $20 just to be certain.

Anyway, thanks for your well written article. It confirmed my understanding of our problem, and it helped my son develop a better understanding of what we were doing and why, as well as the purpose and mechanism behind the earth-fault interrupting circuit. Also, to anyone out there with a Lay-z-spa or other consumer grade hot tub who sees a problem like mine, for god's sake, be careful and don't try to do anything with your unit that might not be safe.

Otherwise you may be in for quite a shock!