Electrician advice

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Soldato
Joined
1 Jun 2005
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5,152
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Kent
If a relay switch that powers 2 sets of plug sockets sudenely trips and wont flip back up, what could be causing it to not stay up? (no jokes about it 'not staying up' please).

Not being an electrician im not sure how they work exactly, but since it cant be fliped back up im gusesing whatever caused the relay to trip in the first place is still causing it to be triped when the relay is turned back on.

One plug socket was compleatly empty when this happened, the other socket had a pc (powered off), laptop (powered off), a cable modem, and a router all pluged into it. I daubt any of these caused the fault because when plugged into a switch on a seperate relay, they work fine without causing the other relay to trip.

With NOTHING pluged into any of the wall sockets that are connected to the tripped relay, the relay still refuses to be turned back on, does this mean the problem lies with either a) the relay itself being faulty, or b) a problem with the wall socket wiring causing power to be set to ground, thus tripping the relay, or c) something else?
 
The relay(breaker) may be faulty but it is more likely doing its job.

Sounds like you have a fault in the circuit somewhere.

You need someone with a little more knowledge to help you investigate
 
well its the weekend, so no way will we pay a proper electrician to come out to check whats the deal, as it would cost too much. And since the plug sockets that are effected arnt essential, a proper electrician can wait for now.
 
wiring/socket is faulty , possible an earth fault



is the mcb lever loose or does it get heavy when you go to off then on, if its the later its a wiring/socket fault , if its slack all the time it could be a duff mcb






AMIEE
 
Well i have no idea how, but it seems to have fixed itself. I went to take a picture of it, and i thought i would try flip the lever up for one last go. it didnt stay up right away, but when i held it up for a few seconds, it now stays up. Not sure why it had to be held up for it to stay up, all the other switches stay up when simply flicked up.

I assumed it was an electrical problem causing the cuircit breaker to keep staying on the off position, but it could just be a slight mechanical problem with the cuircit breaker itself in that it has to be held up for it to lock into the on position.
 
Sounds like either a device is drawing a high inrush current that passes the breakers limit and delay design on start and then going down to normal levels, there might be something on another socket on that circuit doing that. If theres nothing at all on the circuit and the breakers doing that, then it might be faulty and worth replacing tbh.
 
if his sockets are on the ring then it will be 32amp, very rare that it can be 16amp. lights will be 6 amp, although i have seen sockets fed from this mcb which is dangerouse.
 
a 2.5mm² radial on a 20A CPD is a standard circuit in the OSG and is being used more and more.

Nothing specifically prevents sockets on lighting circuits, and this often gets done for 'wallwart' style TV dist amps in attic spaces (though obviously you wouldn't install a general purpose sockets from a lighting circuit!)
 
I've just checked my consumer unit after what Gadge said.

I've noticed that all my sockets around the house are generally on 32A MCBs. However, the sockets in bedroom are run through a 16A MCB. Would it be better to replace the 16A MCB with a 32A MCB?

Oh, btw, I live in a 1 bed flat and almost all the rooms are on their own separate ring (lounge, kitchen, bedroom, each have their own MCB).
 
yeah you could do. Usually immersion heaters where fed off a 16A MCB. If the room has its own ring, then add up everything that is plugged in, in terms of WATTS, and let me know. Or use I(amps) = P(watts)/V(volts) work it out yourself.
 
How do i know if its a 30A MCB? the Breaker itself only has '8032b' writen on it along with 240/400v (if i saw the numbers right that is, the writing was small and hard to make out). On the panel itself that the breakers are attached to, they are split up into 2 sections, and the panel points to this section as 'RCCB 80A, 40mA - do not exceed 90A' or something like that, again, its hard to make out because its just a little hand written sticker.
 
Gadge said:
yeah you could do. Usually immersion heaters where fed off a 16A MCB. If the room has its own ring, then add up everything that is plugged in, in terms of WATTS, and let me know. Or use I(amps) = P(watts)/V(volts) work it out yourself.
Click to expand...

Well, right now, the room is lying empty as Im still in the process of doing it up. But, after its complete, it will have a full AV/computer system along with a 2 piece air conditioner that sucks about 2000w when heating at full power.

Why not simply put in a 40A MCB, say. What could be the possible damage by doing this? Why pussy foot around with 16A and 32A MCBs?

I do have an immersion, however, that is on a separate ring, protected with a 32A MCB, all by itself.
 
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Adam_151 said:
This thread scares me :eek:
Click to expand...

Agreed 100%

You cannot just start swapping MCB ratings without knowing the type and CSA of the cables used on the particular circuit!!

By replacing the 16A MCB with a 32A MCB you are basically doubling the amount of current that can then run in the cable which is potentially VERY dangerous as the cable may not be rated for this amount of current which could result in a FIRE if the cable exceeds its current carrying capacity :eek:


01. Design Current (Ib) = P / V

02. Nominal Current (In) = > Ib
(This is the value of fuse,mcb ..etc)


03. Tabulated Current (It) = In _
.................................Ca Ci Cg Cr

Ca = Ambient Temperature Correction Factor
Ci = Insulation (Thermal) Correction Factor
Cg = Grouping (Cables) Correction Factor
Cr = Re-Wireable Fuse Correction Factor 0.725

04. Insulation Method

05. Cable Run, length & type

06. Work out voltage Drop (Must NOT be more than 4% of Supply Voltage)



Voltage Drop =

mV/A/m x Ib x L .
1000
Click to expand...

DON'T MESS ABOUT WITH ELECTRICS! GET A PROFESSIONAL IN :rolleyes:
 
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if its a ring main and its in 2.5mm, use 32amp MCB. I am a professional.
40amp MCB is for shower circuits and such and that requires at least 6mm cable.
 
Gadge said:
if its a ring main and its in 2.5mm, use 32amp MCB. I am a professional.
40amp MCB is for shower circuits and such and that requires at least 6mm cable.
Click to expand...

It is a ring main and uses 2.5mm cable. It is the same cable that was used in my lounge, yet the lounge was put on a 32A MCB, while my bedroom put on a 16A MCB.

My shower uses 6mm cable and as you stated, is on a 40A MCB. I actually wouldve preferred them to use 10mm cable, so in the future I couldve attached a higher power shower, however, at the time the electrics were done, I was not aware of all these intricacies.

Thanks for tips Gadge. I shall keep them in mind should the circuit in my bedroom start to overload/trip.


M0t0r0la said:
DON'T MESS ABOUT WITH ELECTRICS! GET A PROFESSIONAL IN :rolleyes:
Click to expand...

Somebody said that to me about plumbing. I got a plumber in and he said I should try doing plumbing myself as he believes its a big waste of money calling people in. From that point onwards, I pretty much do all my plumbing for all but the most major of works. Of course, this will soon be put to an end once the Government start requiring for plumbing work (like electrics and gas works) to be certified.

Even if I dont swap the MCBs, its nice to know how things work. A lot of people seem to honestly believe that if they mess in anyway with their electrics, their house will blow up. Or that if they do a little bit of plumbing then their house will end up flooded. Even regulations specify that a 'competent' person can do the simple stuff with regards to electrics and even gas work (as explained earlier in the 'Kitchen buying and fitting' thread).

Im pretty sure that those who dont know how to build PCs think exactly the same way - if I open up the case, it will blow up!

Oh and this one is for Motorola :rolleyes:
 
I am a retired electrician and some of the advice given to you would frighten me.
Yes you can do your own plumbing, as all water can do is drown you and you can see it coming.
Electricity you cant see but it can be deadly if you get it wrong.
In a bedroom you do not normally have that many sockets so a 16a mcb will suffice, in the main room you tend to have not only sockets on the ring main but spurs of them as well, so a 32amcb is normal.
 
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