RCCB trips with no load connected! (United Arab Emirates)

[goodman90]

Hi,

I have a Hager CE464J installed in my house to feed a number of AC split units+some other loads. Sometimes, when I am alone at home, non of the AC are turned on. However, when I wake up at morning, I see that the breaker has tripped.

In order to fine the issue, I decided to trip load CB connected through the RCCB to try to isolate the problem. I ended up tripping all the CBs, and still getting RCCB trip everyday, almost the same time! And once the RCCB trips, I can't reset it unless I wait for at least an hour.

Even worse. If I am running load ( 3 AC units) at night, I get a RCCB trip. But this time, I can reset it immediately. But after 5 minutes, the RCCB trips again. SO i reset the RCCB, but this time, it lasts for the entire night and only trips at sunrise!! which then, the RCCB need to wait for an hour to be resat.

I think I am facing two issues not one. But I am not aware of the proper troubleshooting process. I am thinking of installing a 0.3A RCCB instead of the 0.1A I have now. Other than that, I have no solution.

Sorry for the lengthy post. I appreciate all the help and comments.

regards,

 

[ericmark]

There is two methods of testing earth leakage, one measure the current the other measure to impedance (resistance) both need special test gear. I will guess the A.C. has some heater to de-ice and this is faulty causing the RCD to trip. However in this country we don't use that many A.C. units, so better posted in electrics outside UK.

 

[ban-all-sheds]

In this country we have laws of physics and physiology which say that a 100mA RCD is inadequate for personal protection, and I expect they apply in the UAE too. So depending on why they are required there your 100mA one might already be too high, let alone a 300mA one.

 

[JohnD]

I decided to trip load CB

I don't understand what that means.

If they were single-pole breakers, you could still get an earth leakage trip due to neutral/earth leakage.

You might also consider RCBOs, one per circuit, so only the one(s) with the fault would go off. They will usually fit in the same space as the correct brand of MCB, though 2-pole RCBOs are usually double-width.

The time-of-day tripping does suggest condensation, perhaps in switchgear or even dripping into a conduit.

 

[goodman90]

I don't understand what that means.

If they were single-pole breakers, you could still get an earth leakage trip due to neutral/earth leakage.

You might also consider RCBOs, one per circuit, so only the one(s) with the fault would go off. They will usually fit in the same space as the correct brand of MCB, though 2-pole RCBOs are usually double-width.

The time-of-day tripping does suggest condensation, perhaps in switchgear or even dripping into a conduit.

Thank you for your reply.
You are right. I meant by " trip", opening the single-pole breakers serving the load. does neutral/earth leakage happen if there is no actual current flowing in the circuit?

 

[JohnD]

it can do. Remember also that all the N's are connected together at the busbar, so current flowing through any other circuit will put a bit of voltage on the N of the circuit you are looking at.

 

[goodman90]

it can do. Remember also that all the N's are connected together at the busbar, so current flowing through any other circuit will put a bit of voltage on the N of the circuit you are looking at.

by basbar you mean the one inside my home? ( main Distribution Board )?

if thats true, what do you think the best way to troubleshoot this issue? I am mean what could be the best solution?

 

[JohnD]

DP isolating switches might point you at the circuit with the problem. If the problem one is isolated, your RCD should stop tripping.

RCBOs would also trip on the circuit that has the problem. DP RCBOs even better, would trip and isolate it. But they are bigger, and more expensive.

I wouldn't be surprised if it's condensation. Earth Leakage faults are most often on wet or watery appliances.