Breaker Tripping under unusual circumstance...

[martinwood333]

Hi there all. First off would just like to introduce myself real quick. My name is Martin and I live in Airdrie, Scotland!

My Wife and I have lived in our house for a little over 3 years. For the past year or so, I've been experiencing a rather odd issue (which has gotten progressively worse) with a circuit breaker tripping under very specific circumstances. I personally think it may just need replaced but thought best to look for advice first!.

Going into detail, it is isolated to our gaming room (used to be a bedroom). It only trips when I switch my PC on at the wall (flipping the switch on the wall socket). Upon doing so, 9/10 times the breaker will trip. It only does this with my PC, however the power supply in the PC has also been replaced, as has the cord/plug, with the same results.

I have also tried an adjacent socket, and the same thing happens. I have the PC connected via a 4 socket-strip surge protector (which has also been replaced). I find that unplugging the PC from this surge protector, switching on at the wall, and then plugging the PC back into - the now powered - extension works fine.

In summary, I've tried different sockets, switched off all other loads in the room, changed out the surge protector extension - and also tried just plugging the PC straight into the wall, rebuilding my PC and changing it's power supply, and it will still trip when I turn it on directly at the wall with it plugged in, however unplugging, then switching on the wall socket, and then plugging it in doesn't result in it tripping.

Is the breaker just needing replaced due to wear and tear or could it be possible that something else is going on?

I really appreciate any help or advice that can be provided!

Thanks in advance...

- Martin

PS. I've attached a picture of the exact breaker which is tripping.

 

[telectrix]

i would first determine whether the circuit is a ring or a radial.if it's a ring, then a 32A breaker might be the solution. also, those breakers are quite old and it may just be "tired" and need replacing. the way forward is to get alocal sparks in to do some investigation and testing.

 

[Pete999]

Hi there all. First off would just like to introduce myself real quick. My name is Martin and I live in Airdrie, Scotland!

My Wife and I have lived in our house for a little over 3 years. For the past year or so, I've been experiencing a rather odd issue (which has gotten progressively worse) with a circuit breaker tripping under very specific circumstances. I personally think it may just need replaced but thought best to look for advice first!.

Going into detail, it is isolated to our gaming room (used to be a bedroom). It only trips when I switch my PC on at the wall (flipping the swtich on the wall socket). Upon doing so, 9/10 times the breaker will trip. (It only does this with my PC, however the power supply in the PC has also been replaced, as has the cord/plug, with the same results).

I have also tried an adjacent socket, and the same thing happens. I have the PC connected via a 4 socket-strip surge protector (which has also been replaced). I find that unplugging the PC from this surge protector, switching on at the wall, and then plugging the PC back into (the now powered) extension works fine.

Again, I've tried different sockets, switched off all other loads in the room, changed out the surge protector extension (and also tried just plugging the PC straight into the wall), rebuilding my PC and changing it's power supply, and it will still trip when I turn it on directly at the wall, however unplugging, switching on the wall socket, and then plugging it in doesn't result in it tripping.

Is the breaker just needing replaced or could it be possible that something else is going on?

I really appreciate any help that can be provided!

Thanks in advance...

- Martin

PS. I've attached a picture of the exact breaker which is tripping.

View attachment 39856

So a 16Amp CB looks like it would be a Radial circuit rather than a ring, mind you that's an assumption rather than a fact, questio, do you have any thing else plugged in / connected to that particular circuit? could be that the PC is the straw breaking the Camels back with regards to the loading of the circuit, first to is to find what else is on that circuit, NOT what's just plugged into the socket you are using, but sockets in other areas, try switching off that breaker and check what else if anything doesn't work and come back to us with the results.

 

[martinwood333]

i would first determine whether the circuit is a ring or a radial.if it's a ring, then a 32A breaker might be the solution. also, those breakers are quite old and it may just be "tired" and need replacing. the way forward is to get alocal sparks in to do some investigation and testing.

Thanks for the reply! That's probably the best course of action after it being put that way, as I'm unsure whether it's a Ring or Radial. It didn't occur to me that it would need to be taken into account. Quite a few of the breakers are rather old (old house), so at the end of the day it could just be it's worn. Either way, thanks for the reply! Will investigate a little more and see about getting someone out if need be.

So a 16Amp CB looks like it would be a Radial circuit rather than a ring, mind you that's an assumption rather than a fact, questio, do you have any thing else plugged in / connected to that particular circuit? could be that the PC is the straw breaking the Camels back with regards to the loading of the circuit, first to is to find what else is on that circuit, NOT what's just plugged into the socket you are using, but sockets in other areas, try switching off that breaker and check what else if anything doesn't work and come back to us with the results.

Thanks for the prompt reply also! That's a good shout. I'll confirm this when I get home. I had assumed the breaker fed just the one room, however thinking about it, it's quite possible it's also feeding the adjacent bedroom. Iive just remembered our (also rather old) boiler/3-way valve controller etc. are also in the gaming room in a cupboard, which I believe are likely fed off the same line.

Thanks again! It's much appreciated

 

[SparkyChick]

Switch mode power supplies used in PCs and associated gear can have high in-rush currents.

You described the room as a gaming room... based on my own choices for my rig which I use for gaming, I'm guessing it's quite a substantial PSU in the PC (750w plus)?

When I was staying at my parents place, it was quite usual for the lights to dim the moment I switched my system on (two PCs, laser printer, two monitors). That was on a ring final circuit fused at 30A so never caused a trip, but I suspect it may have tripped a smaller OCPD.

As to why it doesn't trip when you turn the switch on and then connected the PC... could just be the combined load of the PC and everything else... by the time you plug your PC in, the in-rush current from everything else has been dealt with.

 

[Jim90]

I agree with SC, I have a 750W in my rig and I’ve had issues before with 20A radials with high current devices in the kitchen on the same circuit.

Could possibly try running the PC in Eco mode through windows to limit the power your devices can take. At the expense of performance ofcourse!

 

[paul291277]

Not sure I buy into the inrush current thing; whats the difference between flicking the switch on the socket outlet and plugging a load in?

 

[paul291277]

Ahhh.... I retract my last comment, couuld be combined inrush current from everything on your 4 socket-strip surge protector.

Try unplugging other devices and leaving the PC plugged in and see if issue still occurs

 

[martinwood333]

Switch mode power supplies used in PCs and associated gear can have high in-rush currents.

You described the room as a gaming room... based on my own choices for my rig which I use for gaming, I'm guessing it's quite a substantial PSU in the PC (750w plus)?

When I was staying at my parents place, it was quite usual for the lights to dim the moment I switched my system on (two PCs, laser printer, two monitors). That was on a ring final circuit fused at 30A so never caused a trip, but I suspect it may have tripped a smaller OCPD.

As to why it doesn't trip when you turn the switch on and then connected the PC... could just be the combined load of the PC and everything else... by the time you plug your PC in, the in-rush current from everything else has been dealt with.

Sounds spot on! I run an 850W PSU in the PC. Oddly enough, it was October 2016 I rebuilt my machine, with a newer model of PSU (have always run 850W though), and it's since then that it has gotten progressively worse. I should point out a month after the build I had to RMA the PSU due to coil noise but the replacement is the exact same model and wattage which I've run ever since, so I'm doubtful the PSU is faulty.

I have however tried plugging just my PC into the wall socket, without the surge protector/extension, and the same thing happens. Flip the switch, an audible pop, and the breaker trips. I did suspect it could be the cord but I've changed that out also. The in-rush does sound like it could be a factor. If it means anything, there's quite a visible "spark" inside the powered-up extension when I plug the PC into it.

I wonder if the breaker is just so sensitive now that the in-rush is enough to trigger it? I realise now that by design breakers tend to get more sensitive as they age?

I agree with SC, I have a 750W in my rig and I’ve had issues before with 20A radials with high current devices in the kitchen on the same circuit.

Could possibly try running the PC in Eco mode through windows to limit the power your devices can take. At the expense of performance ofcourse!

Thanks! Unfortunately this is before I even touch the power button the PC to boot it up, so I'm not sure making such changes would be beneficial. The breaker trips simply by switching the power on at the wall.

Ahhh.... I retract my last comment, couuld be combined inrush current from everything on your 4 socket-strip surge protector. Try unplugging other devices and leaving the PC plugged in and see if issue still occurs

Yeah as I mentioned to SparkyChick above, I've tried that Same result. It's very odd.

It seems to be specific to my PC. My wife's PC is in the same room, running off the same breaker, however is running an older 650W PSU, and has never had the same problem. Thanks all for the replies again!

I realise a simple solution for this is to just keep it plugged in and switched on at the socket, but I'm not comfortable with leaving anything on that I'm not using.

It's a bit confusing that flipping a switch, or plugging in a plug could give different results

EDIT: Probably worth checking the condition of the wall sockets aswell come to think of it?

 

[marconi]

Could we have posted pictures of the offending sockets and the surge suppressed socket strip?

Could you also take some pictures of the PC's plug's live and neutral pins to see if there are signs of pitting due to arcing?

Also, can you move your PC and plug it into a downstairs switched socket on the ring circuit supplied by the 32A MCB to the right of the 16A one? Then do your x 10 switch on test. Take a picture of the socket you use.

 

[Pete999]

Not really answered my question, only a thanks, obviously not worth responding so I'm not interested any more I 'm out.

 

[martinwood333]

Could we have posted pictures of the offending sockets and the surge suppressed socket strip?

Could you also take some pictures of the PC's plug's live and neutral pins to see if there are signs of pitting due to arcing?

Also, can you move your PC and plug it into a downstairs switched socket on the ring circuit supplied by the 32A MCB to the right of the 16A one? Then do your x 10 switch on test. Take a picture of the socket you use.

Sure thing! I'll get some pics shortly. Currently on the PC in question so will obviously have to shut down and return. Cheers!

Not really answered my question, only a thanks, obviously not worth responding so I'm not interested any more I 'm out.

Wow. Sorry Pete. I appeared to have missed your reply. Nothing personal. A combination of working whilst on the forum at the same time and being short of time. I apologise, but if you feel that way, then thanks anyway.

I've actually done just as Pete said, and discovered that the previous homeowner has gotten mixed up with writing on which breaker is which. Anyway, I turned off the offending breaker, and it seems it's supplying ALL of the upstairs sockets... not just the ones in the gaming room. Is that right? 16A for upstairs yet 32A for downstairs?



UPDATE: Ok, I've taken some pictures and attached them. I am surprised to see that yes indeed there is pitting on the L and N pins.



I will attempt to take my PC downstairs this evening and plug it into one of the sockets on the 32A breaker and will be back with the results Again, I really appreciate the help in narrowing down this rather frustrating fault.

 

[Wilko]

I will attempt to take my PC downstairs this evening and plug it into one of the sockets on the 32A breaker ...

Hi Martin - if you've an extension lead that might save your back

 

[Des 56]

What switching are the sockets ? are they single or double pole

If there is a staggered opening of the switch contacts (live and neutral of the socket)and they do not break at the same time,its possible the Rcd sees this as a imbalance with the type of load being switched

 

[shaun1]

Have you tried inserting the power cable/plug as a power on method before trying the switch, or only after using the switch has tripped the breaker. I ask this because (at least some of) the large inrush current will charge capacitors in the PSU which may have built up some charge from power ups that have tripped the breaker by the time you resort to unplugging and re plugging. I have also been told in the past that inrush curent can vary due to the point in the a.c. mains cycle when the circuit is made.

The arc damage you see on the plug pins will only get worse, especially if used to make/break a large inductive load. The plug should be replaced, and any sockets it has been used in should be checked for similar damage.

 

[westward10]

Delete.

 

[martinwood333]

Hi Martin - if you've an extension lead that might save your back

Right you are!

Also, can you move your PC and plug it into a downstairs switched socket on the ring circuit supplied by the 32A MCB to the right of the 16A one? Then do your x 10 switch on test. Take a picture of the socket you use.

Done this method, and no tripping at all on the downstairs 32A circuit. I think it's pretty definitive the 16A breaker may be to blame?

What switching are the sockets ? are they single or double pole

If there is a staggered opening of the switch contacts (live and neutral of the socket)and they do not break at the same time,its possible the Rcd sees this as a imbalance with the type of load being switched

This, I'm not sure about. I'll have to have a look. I see how that would make sense. Good shout!

Have you tried inserting the power cable/plug as a power on method before trying the switch, or only after using the switch has tripped the breaker. I ask this because (at least some of) the large inrush current will charge capacitors in the PSU which may have built up some charge from power ups that have tripped the breaker by the time you resort to unplugging and re plugging. I have also been told in the past that inrush curent can vary due to the point in the a.c. mains cycle when the circuit is made.

The arc damage you see on the plug pins will only get worse, especially if used to make/break a large inductive load. The plug should be replaced, and any sockets it has been used in should be checked for similar damage.

That's a good point. Usually whenever it's tripped I resort to my plug-in-while-the-socket-is-on method, or as of recent it's the only method I'll use as I'm not comfortable risking it tripping. It makes an audible POP sometimes when it happens, coming from either socket or PSU - can't really tell, but it's not a good sound.

It'll trip after my PC has been off for a good while, but not attempted it by using the switch immediately after the PC has been powered up and shut down, in quick enough succession that there is still charge in the PSU. I guess if it didn't trip, then it would signify in-rush is the definite cause?

Yeah the newly discovered damage is concerning me, and has really made me want to take care of this pretty urgently after putting it off for so long. Just found out my father-in-law knows a certified electrician. I've asked him to see if he'll be able to come round and witness it for himself and see what he makes of it aswell.

The whole fact that the upstairs sockets are on a 16A Type B breaker, whilst downstairs and kitchen sockets are on 32A Type 1 breakers, has me a tad confused. Obviously will need to confirm the wiring is of the suitable gauge before making any changes in that regard.

For sure though, I'll mention I've been in touch with you good folks and that I've attempted the diagnosis methods you've all mentioned, aswell as the potential causes.

 

[westward10]

Delete.

 

[SparkyChick]

The pop you here is the arc at the moment the plug pins make contact with the socket contacts. It results in the visible flash you mentioned in an earlier post and it's what causes the pitting in the plug pins (or the switch contacts).

It may be sensible to split the load up somewhat, but don't do it with switched extension leads as I found they have a tendancy for the contacts to weld together (this is how I staggered the in-rush... until the switch contacts fused).

 

[marconi]

One could suggest increasing the MCB supplying the socket to a 20A one provided that the wiring and its method of installation allow. But as Jim90 said in #6 I suspect you will still have occasional problems.

I reckon the robust solution is to provide a 32A MCB protected sockets circuit to the first floor. At the same time you can have an adequate number of sockets installed to dispense with the socket strips. The problem is high peaky inrush current - there are some big capacitors in the 850PSU for smoothing, filtering and active power factor correction. If you want to continue with surge protection MK do a double socket but they are not cheap. If it was me I would not bother with SP - the electronic components inside them lose their efficacy over time as they quench transients; in the case of MK one has to change a cartridge to renew the SP capability but if I remember correctly there is no indication of their state of decay to decide when it has to be done. Perhaps just insure your computers instead and unplug them during episodes of lightning.

So, time to call an electrician methinks.

SMPSU current waveform:

Tutorial-Pwer Meter Calibration - Yokogawa Test & Measurement Corporation - https://www.yokogawa.com/ymi/tutorial/tm-tutorial_wt_03.htm

Corsair850PSU:

RM Series™ RM850 — 850 Watt 80 PLUS® Gold Certified Fully Modular PSU - http://www.corsair.com/en-gb/rm-series-rm850-80-plus-gold-certified-power-supply