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Active Contributor

Join Date: May 2010
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Connections to an ELCB?

10/16/2010 3:48 AM

I have below shown ELCB of "legrand" being installed at my home. My home is with a single phased connection. Recently there was an incident that my mixie blown off its motor even when the supply was not there .. and there happened a spark in the power outlets where my mobile chargers were just plugged in. Mixie blown up its winding and charger is not working.

Then I checked if the ELCB was working by pressing the TEST button... but nothing happened.

I wonder if this is because of wrong connections to ELCB where it is not tripping when TEST button is pressed or because of a malfunction of the ELCB.

In the below picture, I find a total of four wires goes to the top and to bottom. The right end of it is written with letter 'N' which I think is for neutral wire connection.

I am not an electrician and totally blank about the way electricity works. Can I be advised about this? (forgot to mention one thing - I think I remember this ELCB had tripped off once there was lightning)

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Anonymous Poster
#1

Re: Connections to an ELCB?

10/16/2010 4:04 AM

ELCB connection, leave it to licenced electrician more over you got an MCB in your home connected series in circuit?

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Guru
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#2

Re: Connections to an ELCB?

10/16/2010 4:11 AM

1. If your home has a sigle phase supply, only two wires would come from the utility supply - one phase and one neutral. Not 4 wires.

2. ELCB (better called RCCB) will only prevent you and your family getting an electric shock, and also prevent any earth leakage through damaged insulation. It will NOT protect any equipment and the source against short circuit. Your distribution board should have MCBs for that purpose.

3. Since you have a 4-pole RCCB where you should have a 2-pole one, the test button may be in the wrong line. If your incoming 'hot' line is in the circuit where the test button is wired, it will trip when you press it. It will be simulating an earth leakage.

i am not able to think of why your mixie and charger blew, maybe there were some other faults, not necessarily EF.

The electrician who did your house wiring seems to have not done a professional job. Legrand is a good company, and it is unlikely that the RCCB is faulty. You can call them and ask them to check, they have a reputation to protect, and will come and check. Good luck.

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Guru
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#3
In reply to #2

Re: Connections to an ELCB?

10/16/2010 11:32 AM

GA.

But I think the important issue here is in this part of the OP:

"I am not an electrician and totally blank about the way electricity works"

How then can we assume he knows what he has coming into his service? How do we know it isn't a 3 phase service and only his loads are single phase? It may indeed be the correct RCCB and correctly connected.

rajkochi,

This is something best left to professionals, I strongly encourage you to invest in having it looked at by one to make sure this is done right. The lives of you and your loved ones may be at risk, electricity is not something that should be tackled by novices who are "totally blank about the way electricity works". But bravo for admitting it, that's the first step towards safety!

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Guru
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#5
In reply to #3

Re: Connections to an ELCB?

10/17/2010 2:44 AM

Did you notice that someone cancelled the GA you gave me? Takes all kinds i guess.... thanks anyway.

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Anonymous Poster
#8
In reply to #5

Re: Connections to an ELCB?

10/17/2010 3:45 AM

The correct answer was for the OP to get an electrician.

The desire to experiment can get people killed - especially as the OP has no idea of the voltage coming in or anything else.

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Active Contributor

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#6
In reply to #3

Re: Connections to an ELCB?

10/17/2010 2:50 AM

Hi JRaef,

Thanks for your advise on safety.. and I would like to follow that. But being a person who is interested to do experiments by taking 'calculated' risks.. I just wanted to clear my doubt here. Neverthless to say that I know those simple basics... and the incoming supply to my home. Moreover, this blog has educated me more on this...

http://electricalinstallationwiringpicture.blogspot.com/2010/02/1-phase-elcb-connection-pictures.html

thanks to Wan for the above blog.

But as you may notice, it is about a single phase ELCB (or RCCB).

Today again I have checked the wiring... I have noticed that, even though there is no second and third phase, a dummy connection is given there for both. There are a total of four wires including one N going out from the Switch-Fuse but only two wires from Meter is going into the Switch-Fuse. I have used a tester to check which one is phase and N. Following the phase and N, I could verify that N goes into the N pole and Phase goes to the T pole of ELCB. All the four wires including N going out from Switch-Fuse is connected to the bottom poles of ELCB (But N is connecting to N of ELCB) and all these goes out from ELCB to the MCBs. Irrespective of whether its a single phase or three phase connection, if the phase line is connected to the pole where it is to be connected and N is connected to the pole where it is to be connected.. why it is not tripping off???

I have noticed another thing as well, when I just touched the phase wire coming out from Switch-fuse going to ELCB, my tester was glowing ?!!!! I just touched the outer sheath of the phase wire...and no where else...!!!!!

Thanks for your help

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#7
In reply to #2

Re: Connections to an ELCB?

10/17/2010 2:53 AM

Thanks kvsridhar,

Regarding your point # 2:

Today again I have checked the wiring... I have noticed that, even though there is no second and third phase, a dummy connection is given there for both. There are a total of four wires including one N going out from the Switch-Fuse but only two wires from Meter is going into the Switch-Fuse. I have used a tester to check which one is phase and N. Following the phase and N, I could verify that N goes into the N pole and Phase goes to the T pole of ELCB. All the four wires including N going out from Switch-Fuse is connected to the bottom poles of ELCB (But N is connecting to N of ELCB) and all these goes out from ELCB to the MCBs. Irrespective of whether its a single phase or three phase connection, if the phase line is connected to the pole where it is to be connected and N is connected to the pole where it is to be connected.. why it is not tripping off???

I have noticed another thing as well, when I just touched the phase wire coming out from Switch-fuse going to ELCB, my tester was glowing ?!!!! I just touched the outer sheath of the phase wire...and no where else...!!!!! WHY????

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Guru
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#9
In reply to #7

Re: Connections to an ELCB?

10/17/2010 4:09 AM

Curiously, i have a 4-pole RCCB as the incomer in my flat also, since the brand i wanted 15 years ago was not available in 2-pole version. No matter, my electrician used T and N as the poles, leaving the other two blank. When i tried the "Test trip" function, it did not trip. So i asked the electrician to shift the wiring to R pole. Voila ! It tripped now. This button simulates an earth leakage and trips the RCCB. Ideally you must test it once a month. What a tragedy if it welds in closed position and cannot trip when someone is getting electrocuted ! Believe me, mine trips every time, even after 15 years in service.

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Anonymous Poster
#4

Re: Connections to an ELCB?

10/17/2010 2:35 AM

You seem to have 3 phase supply incoming, even though you may be utilising single phase only. If your "earth leakage" unit is suspect then get a certified electrician in to check out the complete instalation, especially considering you may have suffered from a lightning strike. You and your family will suffer if you start to "play"

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#10

Re: Connections to an ELCB?

10/17/2010 10:57 AM

Are you sure you have single phase supply,verify from an electrician.If so install a 2pole RCD.

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#11

Re: Connections to an ELCB?

10/19/2010 4:46 AM

If the neutral does not pass through it, then it won't trip when the Test button is pressed.

If in doubt, consult a qualified electrician.

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