mcb tripping

[nabby68]

thanks andrew. so can you tell me why when i do touch the earths together that it does trip the mcb?

 

[andy]

thanks andrew. so can you tell me why when i do touch the earths together that it does trip the mcb?

dpends. but since im not there to test the system i cannot say. altho if it trips and RCD and no MCB its mire likely sine the RCD needs 30mA to trip, compared to 32A for the MCB

 

[Lectrician]

so can you tell me why when i do touch the earths together that it does trip the mcb?

Because you are reconnecting the faulty part of the circuit.

Lucky you didn't touch the earth which was under fault before you touched them together.

Chock blocks on every socket to test - sounds like like you shouldn't be doing what you are doing.

I expect it is a 30mA RCBO and possibly a 100mA main RCD. This sounds the most logical to me.

Just because the socket where you touch the two earths together causes the breaker to go, doesn't mean it is that socket. You are touching two earths and completing the REST of the circuit - look from that pont onwards.

 

[nabby68]

hi andrew. dont really get your last post

dpends. but since im not there to test the system i cannot say. altho if it trips and RCD and no MCB its mire likely sine the RCD needs 30mA to trip, compared to 32A for the MCB

how can it trip the mcb as you put it when there is no current going throught the circuit?

 

[Lectrician]

I think he typed mighty quickly

 

[andy]

hi andrew. dont really get your last post

dpends. but since im not there to test the system i cannot say. altho if it trips and RCD and no MCB its mire likely sine the RCD needs 30mA to trip, compared to 32A for the MCB

how can it trip the mcb as you put it when there is no current going throught the circuit?

where did the last part come from?

 

[nabby68]

ok guys here is a further update.

the circuit that i thought was a ring now turns out to be two radials connected to a 32amp mcb.

my first question is, is this acceptable or should the radials be on seperate mcb's?

and my second is i have narrowed the fault down to between two sockets on one of the radials, so would it be advisable for me to test between these two socket to find out the exact fault or just replace the cable between the two sockets since i am 99.9% certain that this is where the problem is?

 

[andy]

ok guys here is a further update.

the circuit that i thought was a ring now turns out to be two radials connected to a 32amp mcb.

my first question is, is this acceptable or should the radials be on seperate mcb's?

and my second is i have narrowed the fault down to between two sockets on one of the radials, so would it be advisable for me to test between these two socket to find out the exact fault or just replace the cable between the two sockets since i am 99.9% certain that this is where the problem is?

what are the radials wired in? if its 2.5 then they should be on a 20A MCB, possibly 16A

 

[nabby68]

the radials are wired in 2.5
so could you explain as to why they should be on a 20 amp mcb or a 16 amp mcb

thanks andrew

 

[andy]

the radials are wired in 2.5
so could you explain as to why they should be on a 20 amp mcb or a 16 amp mcb

thanks andrew

because 2.5mm is only de3signed for 27A. not 32. so if there is a fault, your house could have burned down before the mcb trips

 

[nabby68]

thanks again andrew.
will change put the two radials onto 20amp mcb's

also can you advise what to do in my second question in my previous post ie the best remedy for the fault.

and also what is the difference between a mccb and rcd?

 

[andy]

thanks again andrew.
will change put the two radials onto 20amp mcb's

also can you advise what to do in my second question in my previous post ie the best remedy for the fault.

and also what is the difference between a mccb and rcd?

an mccb doesnt exist for a start.

MCB detects overcurrent. like a fuse. RCD detects earth leakage
RCBO has both in 1

as for the fault, find it first then do something about it. no good just sayin you know where it is

 

[pdcelec]

an mccb doesnt exist for a start.

mccb = Moulded Case Circuit Breaker but I would very much doubt if he has one in his house

 

[andy]

an mccb doesnt exist for a start.

mccb = Moulded Case Circuit Breaker but I would very much doubt if he has one in his house

never herd of 1

 

[pdcelec]

used mainly for large offices and industrial work here is a link of some http://www.memonline.com/fmps.html