Socket MCB Keeps Tripping

[leedrummond]

ok Full story

Moved into my first property here about 6 months ago, never had a problem before, but obviously as we settling in more and more appliences in the house, 3 pcs, Fridge, microwave, washing machine, tumble dryer etc etc, 42 inch tv, virgin media, amp etc
The house is approximately 20 years old Max, so its pretty new, regarding installation i would guess ?

The Consumer unit has all the sockets in the house on 1 16a Hager MCB
( 2 red wires going into the top of the mcb ) this mean its a ring ?


Anyway, last week i replaced the power supply in my pc to a 600w one to give me more power for gaming etc.

Now each time i turn it on and say the other computers are on too, it trips the MCB

Ill go downstairs and reset it ,then turn pc on then it holds in and is fine

What i have come on here for is some advice on what to do now ?

Ive jsut been to the local electrical store and replaced the 16a mcb with another 16a mcb, to check to see if the old 1 was tired / worn, but it still seems to do it on the new one. However this one does hold in slightly better

What is the maximum MCB i can replace the 16a with ?

 

[industryspark]

ring circuits are normally wired in 2.5mm conductors and a 32A mcb....
are you sure its a ring? could it not be a radial with 2 feeds from the mcb? you cant just go upgrading the mcb without first establishing what type of circuit you have and what condition it is in.......i.e if it is a ring is the continuity ok?, efli ok? IR?

some more investigation is needed.

on the subject of the mcb tripping then if you do have a 16A socket circuit for all your appliances then this isnt very much so when you overload it (too many things on at same time) then it is only doing its job by tripping.

 

[leedrummond]

hi, yes this is jsut what i am thinking, it is overloaded perhaps

i wont go and stick anyhting bigger in ther efor the reasons you have said, it does need looking into

erm im not sure if its a radial or not,

 

[leedrummond]

 

[industryspark]

if you have a lot of things running/plugged in then 16A soon gets surpassed and the mcb will trip.......what im saying is that the setup you have is therefore not fit for purpose.

without insulting you i would suggest you get someone in because your either going to have to modify the circuit or install addiational circuits.

with you not being an electrician your not going to have the knowledge to do this( not trying to be offensive-just the way it is!)

 

[industryspark]

looking at the picture you have posted i would say that the live conductors going into the mcb we are talking about are 2.5mm in size.....im saying this by comparing them to the conductors in the 6A mcb (presumably lighting circuit) which i would expect to be 1.5mm/1mm.

this would indicate a ring circuit but this does need confirming before changing the mcb to a 32A. full continuity tests and IR tests are needed.

 

[leedrummond]

whats the avarage cost of a job like this likely to be ?

 

[leedrummond]

ok cheers

I took that pic to try and give you the full picture to compare against the other circuits

I thought they were 2.5 mm and yes you are correct the 1.5mm 6a mcb is for the lighting circuit

Ok

ill get the continuity and Insulation resistance testing done , hopefully then if al lclear i can replace with a 32a mcb rather than the 16a or 20a as this would not give me much more room to play with

 

[industryspark]

impossible to say mate..... whats the condition of the existing circuit? how many new points would you require? new circuit needed or not? so many questions!

if you do have a ring circuit that is ok and only the mcb needs swapping & then testing then it wont cost much but IF's a big word.

i would suggest getting 3 qoutes from recommended sparks and going with your gut feeling.

 

[Adam_151]

Yeah, agree with the other advice, you really need someone in, you cannot just assume its a ring (one the of the circuits here is similar, two 2.5mm² cables leaving a type 2 16A breaker, but its a branched radial not a ring)

As for the computer PSU, it can happen on B16 breakers sometimes, when the supply is switched on the capacitor inside charges causing a short surge of many amps, breaker trips, when you reset it its mostly charged so it doesn't do it again, in europe where 16A socket circuits are common they use C16 breakers as they are less sensitive to this type of thing (but you *cannot* just swap one in without doing tests to make sure its suitable)

[the letter on a breaker tells you how sensitive the breaker is to start up surges, etc, B is general purpose, C is used for industrial and commerical lighting and motors, air conditioners, etc and D is not often seen and would be for things like welders, X-ray machines, etc]

 

[JohnD]

..it usually helps to start by asking friends and neighbours if they know a local electrician they recommend. If you know someone in a building trade he may know someone who seems good. personal recommendation is worth a lot more than an ad in the local paper.

Phone and ask if he is a member of a self certification scheme, and which one (if not, he may possibly be unqualified or an odd-job man, though he might also be an industrial electrician who does not usually do houses). then ask how long he has been a full member (it may be better, for you, not to have someone who started work just last week).

 

[leedrummond]

cheers guys for your help so far.

 

[mike++]

The switch mode PSUs in PCs can pull a very hefty inrush current from cold and this may pop the MCB. Industrial MCBs come with 4 inrush profiles A,B, C and D, which allow it several times the rated current for a few milliseconds before tripping. A's trip sooner; D's trip later (but D's are normally used for starting motors or DC drives with very high inrush e.g. 160A).

Maybe you could try an MCB with a C curve instead of a B? But get advice from a domestic electrician as to whether you can do this.

 

[leedrummond]

ohh interesting, this was mentions previously in the thread

can a C type be added onto my consumer board? ie 16a C type

 

[JohnD]

it would be preferable to have a B32 ring, but it will need inspection and test to see how to fix it.

a 16A will always trip when you have a couple of big loads on it, such as a washing machine and tumble drier. Sometimes even a kettle and toaster and something else.