MCB 32A TRIPPING

[dt2008]

I'm am not an electrician so don't get too tech on me please

Okay , So yesterday the 32A mcb on my unit started to trip , 1st time it went off I simply reset it , Then 1 hour later it went off again ...Time to eliminate white goods , So i put all white goods / boiler included on a seperate circuit 1 at a time and it still tripped out sometimes 30 minutes and up to an 1hr 30mins , Turned off main power and swapped 32a mcb for another 32a mcb in the panel just to rule out a faulty mcb ....Still it tripped so I kep resetting it until i gave up and started to run the important items off of extension leads from other circuits in the house . So then today I bought one of those socket testers from b&q and tested all sockets , All ok .

The question is becasue it's the only thng I can think of ....Is yesterday when the wife was cooking the christmas dinner she never opoened any of the kitchen windows and there was a HUGE amount of condensation in the kitchen , Could this be casuing the trippping ? and if it is , Is a case of the tripping will stop once whatever is damp dries out ? At the moment the fridge is on a extension on a different circuit and its been over 2 hours since the last trip

 

[Gees]

Condensation could cause the RCD to trip but for a 32 Amp MCB to trip after a legnth of time would indicate a live/neutral current enough to operate the thermal ( bi metal strip ) part of the MCB. such a current in my opinion would not flow even if the uncovered cables where immersed in water. ( I may be wrong though ). Even a current of 20 amps would indicate a 5kw power consumption.Something would be getting mighty hot..

 

[flameport]

Dampness will cause an RCD to trip - the current required to do this is tiny (0.03 amps). However to trip a 32A MCB, significantly more than 32A must be flowing through the circuit.

Even at 32A, this represents almost 8kW of heating at the point where the fault is - easily enough to cause a fire. As the circuit has tripped many times already, it is very likely that the cable at the fault location has been seriously damaged by overheating.

 

[Gees]

Dampness will cause an RCD to trip - the current required to do this is tiny (0.03 amps). However to trip a 32A MCB, significantly more than 32A must be flowing through the circuit.

Even at 32A, this represents almost 8kW of heating at the point where the fault is - easily enough to cause a fire. As the circuit has tripped many times already, it is very likely that the cable at the fault location has been seriously damaged by overheating.

we submitted at exactly the same time LOL

 

[dt2008]

Dampness will cause an RCD to trip - the current required to do this is tiny (0.03 amps). However to trip a 32A MCB, significantly more than 32A must be flowing through the circuit.

Even at 32A, this represents almost 8kW of heating at the point where the fault is - easily enough to cause a fire. As the circuit has tripped many times already, it is very likely that the cable at the fault location has been seriously damaged by overheating.

Any ideas where to check for damage ? Surely there would be some sort of smell ?


Can it cause a fire or will it trip before this happens ?

 

[Gees]

Dampness will cause an RCD to trip - the current required to do this is tiny (0.03 amps). However to trip a 32A MCB, significantly more than 32A must be flowing through the circuit.

Even at 32A, this represents almost 8kW of heating at the point where the fault is - easily enough to cause a fire. As the circuit has tripped many times already, it is very likely that the cable at the fault location has been seriously damaged by overheating.

Any ideas where to check for damage ? Surely there would be some sort of smell ?


Can it cause a fire or will it trip before this happens ?

If you do have a 5-8Kw dissipation somewhere there should be a smell !!
If you have an intermittent short live/neutral this will trip the electromagnetic part of the MCB and in this case there may be no signs of anything wrong as the high currents only flow foa very short time.
If you switch off everything in your home and then see how fast the electricity mter wheel turns you will be able to tell if there is a current flowing all the time ( a 8kw load will spin the wheel quite quickly )

 

[dt2008]

Dampness will cause an RCD to trip - the current required to do this is tiny (0.03 amps). However to trip a 32A MCB, significantly more than 32A must be flowing through the circuit.

Even at 32A, this represents almost 8kW of heating at the point where the fault is - easily enough to cause a fire. As the circuit has tripped many times already, it is very likely that the cable at the fault location has been seriously damaged by overheating.

Any ideas where to check for damage ? Surely there would be some sort of smell ?


Can it cause a fire or will it trip before this happens ?

If you do have a 5-8Kw dissipation somewhere there should be a smell !!
If you have an intermittent short live/neutral this will trip the electromagnetic part of the MCB and in this case there may be no signs of anything wrong as the high currents only flow foa very short time.
If you switch off everything in your home and then see how fast the electricity mter wheel turns you will be able to tell if there is a current flowing all the time ( a 8kw load will spin the wheel quite quickly )

Cool idea , Albiet I have a digital meter but i'm still going to try it in fact I have one of those meter things from southern enrgy that tell you how much you are using , Im going to plug that in for a bit

But serioulsy what is the chance of a fire occuring if I leave the mcb in the on position , Will it trip again ? Or is there a chance of a fire ?

 

[flameport]

Places to check would be at socket outlets or other accessories - loose terminals or damaged wires. Other than that it could be a damaged cable almost anywhere.
Overheating like that will certainly cause a smell and probably smoke as well - but if this was under the floor, in a wall cavity or similar it might not be apparent.

However please confirm that the device which is tripping is actually an MCB - is does not have a test button on it.

 

[dt2008]

Places to check would be at socket outlets or other accessories - loose terminals or damaged wires. Other than that it could be a damaged cable almost anywhere.
Overheating like that will certainly cause a smell and probably smoke as well - but if this was under the floor, in a wall cavity or similar it might not be apparent.

However please confirm that the device which is tripping is actually an MCB - is does not have a test button on it.

Def MCB , Proteus geyer B32 not a test button in sight

 

[RF Lighting]

The MCB tripping is doing it's job and preventing a fire from starting in the first place. Continual resetting starts to defeat the purpose of it, and could lead to more problems.

If you can manage to leave the circuit off whilst you track down what the problem is, I think that would be a good idea.

 

[dt2008]

Dampness will cause an RCD to trip - the current required to do this is tiny (0.03 amps). However to trip a 32A MCB, significantly more than 32A must be flowing through the circuit.

Even at 32A, this represents almost 8kW of heating at the point where the fault is - easily enough to cause a fire. As the circuit has tripped many times already, it is very likely that the cable at the fault location has been seriously damaged by overheating.

Any ideas where to check for damage ? Surely there would be some sort of smell ?


Can it cause a fire or will it trip before this happens ?

If you do have a 5-8Kw dissipation somewhere there should be a smell !!
If you have an intermittent short live/neutral this will trip the electromagnetic part of the MCB and in this case there may be no signs of anything wrong as the high currents only flow foa very short time.
If you switch off everything in your home and then see how fast the electricity mter wheel turns you will be able to tell if there is a current flowing all the time ( a 8kw load will spin the wheel quite quickly )

Cool idea , Albiet I have a digital meter but i'm still going to try it in fact I have one of those meter things from southern enrgy that tell you how much you are using , Im going to plug that in for a bit

But serioulsy what is the chance of a fire occuring if I leave the mcb in the on position , Will it trip again ? Or is there a chance of a fire ?

Right I've plugged in the usage meter and on in the house at the moments is

TV
Boiler (running)
Fridge
Few lights
PC
Phones
Outside courtesy light

Its saying im pulling 1.08kw , Does that sound about right ?

 

[Gees]

get your torch out and turn off all everything. then see what it says !

 

[dt2008]

Just humour this one ......

Kettle just plugged into socket , Not turned on , Not boiling any water , Just plugged in the socket with the switch on the socket in the on position , Could this be causing the trip ?

 

[dt2008]

get your torch out and turn off all everything. then see what it says !

Just did it apart from the thing I can't turn off pc etc , It went down to 375 watts

 

[flameport]

Kettle or any other appliance - no, since it will have a 13A (maximum) fuse in the plug, which would have blown already if 32+ amps was going through it.