Discuss MCBs tripping randomly? in the UK Electrical Forum area at ElectriciansForums.net

So the last time I saw a fault like / similar to this was around 35 or so years ago and the memory is a little bit hazy about it but I do recall the problem ended up as a DNO distribution issue

Now to get a bit more background where is this property located is it urban, semi rural or rural, how is the supply delivered is it underground or overhead,

Does this random tripping occur more or only during episodes of wet weather

What connected loads does the garage have, are there any PIR controlled outdoor lights supplied from the garage

While trying to identify the fault have you done any random voltage checks of the main supply at different times to see if there are any large variations that may suggest an external mains issue
 
So the last time I saw a fault like / similar to this was around 35 or so years ago and the memory is a little bit hazy about it but I do recall the problem ended up as a DNO distribution issue

Now to get a bit more background where is this property located is it urban, semi rural or rural, how is the supply delivered is it underground or overhead,

Does this random tripping occur more or only during episodes of wet weather

What connected loads does the garage have, are there any PIR controlled outdoor lights supplied from the garage

While trying to identify the fault have you done any random voltage checks of the main supply at different times to see if there are any large variations that may suggest an external mains issue
Hello mate thanks for your message.
I live in an semi urban set of new builds on the outside of town. I’m pretty sure all the cables are ran underground because there’s a subby not 100ft from my house.

I do have an outside light that hasn’t work for some time now that is on a pir, I didn’t think to look at that since the 6A MCB baby ever tripped that controls it. I will diss connect it tonight to test!

As far as the voltage checks I seem to get a level 240V when I’ve checked, but I will double check again to be sure!

Cheers, Lewis
 
Hello. Please would you tell me:

1. The make, model and power of your gaming PSU. Do you have more than one?
2. Do you plug them directly into a socket or via a surge suppression socket strip?
3. When you say nothing is on do you mean the PC, IT and gaming equipment including PSU is switched off on the equipment or at the socket?
4. Co-incident with moving the equipment to the sunhouse have you added any equipment or changed any of it?
5. Have you tried leaving the 40A mcb off for a few days to isolate power to the sunhouse and the equipment in there?
6. What white goods do you have ie washer, dryer, dishwasher and microwave? Have these changed recently?
7. Do you have an induction hob?
8. Have you had a smart meter fitted recently or at all?
9. Do your lights ever flicker? Do your neighbours ever?
10. Has any digging been done in the garden near the cable to the sunhouse?
11. Have you had any water leaks or rain water ingress to your home of sunhouse?
12. Who did the electricity supply to the sunhouse? Do you have a test certificate if it was done after the main house? How long is the cable run?
13. Would you say the problem never happened until the shift of equipment to the sunhouse?
14. Do you have an electric vehicle charger?
15. What exactly is fed by each circuit breaker - a labelled picture would be helpful.
16. Do you have air conditioning units or heat pumps?
17. Please post a picture of your supply intake and meter.

My hypothesis is you have a loose line, neutral or earth connection(s) - within or without your property - which is causing high dV/dt of the supply voltage; a or several connected loads have mains filters within them which are reacting to the high dV/dt with a high albeit brief current as their capacitors change their state of charge. I suspect the circuit for the sunhouse since it has used unusually split concentric cable which needs care terminating well. The reliable conduction of a connection or joint can vary with current density.
 
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Hello. Please would you tell me:

1. The make, model and power of your gaming PSU. Do you have more than one?
2. Do you plug them directly into a socket or via a surge suppression socket strip?
3. When you say nothing is on do you mean the PC, IT and gaming equipment including PSU is switched off on the equipment or at the socket?
4. Co-incident with moving the equipment to the sunhouse have you added any equipment or changed any of it?
5. Have you tried leaving the 40A mcb off for a few days to isolate power to the sunhouse and the equipment in there?
6. What white goods do you have ie washer, dryer, dishwasher and microwave? Have these changed recently?
7. Do you have an induction hob?
8. Have you had a smart meter fitted recently or at all?
9. Do your lights ever flicker? Do your neighbours ever?
10. Has any digging been done in the garden near the cable to the sunhouse?
11. Have you had any water leaks or rain water ingress to your home of sunhouse?
12. Who did the electricity supply to the sunhouse? Do you have a test certificate if it was done after the main house? How long is the cable run?
13. Would you say the problem never happened until the shift of equipment to the sunhouse?
14. Do you have an electric vehicle charger?
15. What exactly is fed by each circuit breaker - a labelled picture would be helpful.
16. Do you have air conditioning units or heat pumps?
17. Please post a picture of your supply intake and meter.

My hypothesis is you have a loose line, neutral or earth connection(s) - within or without your property - which is causing high dV/dt of the supply voltage; a or several connected loads have mains filters within them which are reacting to the high dV/dt with a high albeit brief current as their capacitors change their state of charge. I suspect the circuit for the sunhouse since it has used unusually split concentric cable which needs care terminating well.
Wow thanks for taking the time to write all that.
Hello. Please would you tell me:

1. The make, model and power of your gaming PSU. Do you have more than one?
2. Do you plug them directly into a socket or via a surge suppression socket strip?
3. When you say nothing is on do you mean the PC, IT and gaming equipment including PSU is switched off on the equipment or at the socket?
4. Co-incident with moving the equipment to the sunhouse have you added any equipment or changed any of it?
5. Have you tried leaving the 40A mcb off for a few days to isolate power to the sunhouse and the equipment in there?
6. What white goods do you have ie washer, dryer, dishwasher and microwave? Have these changed recently?
7. Do you have an induction hob?
8. Have you had a smart meter fitted recently or at all?
9. Do your lights ever flicker? Do your neighbours ever?
10. Has any digging been done in the garden near the cable to the sunhouse?
11. Have you had any water leaks or rain water ingress to your home of sunhouse?
12. Who did the electricity supply to the sunhouse? Do you have a test certificate if it was done after the main house? How long is the cable run?
13. Would you say the problem never happened until the shift of equipment to the sunhouse?
14. Do you have an electric vehicle charger?
15. What exactly is fed by each circuit breaker - a labelled picture would be helpful.
16. Do you have air conditioning units or heat pumps?
17. Please post a picture of your supply intake and meter.

My hypothesis is you have a loose line, neutral or earth connection(s) - within or without your property - which is causing high dV/dt of the supply voltage; a or several connected loads have mains filters within them which are reacting to the high dV/dt with a high albeit brief current as their capacitors change their state of charge. I suspect the circuit for the sunhouse since it has used unusually split concentric cable which needs care terminating well. The reliable conduction of a connection or joint can vary with current density
Hello. Please would you tell me:

1. The make, model and power of your gaming PSU. Do you have more than one?
2. Do you plug them directly into a socket or via a surge suppression socket strip?
3. When you say nothing is on do you mean the PC, IT and gaming equipment including PSU is switched off on the equipment or at the socket?
4. Co-incident with moving the equipment to the sunhouse have you added any equipment or changed any of it?
5. Have you tried leaving the 40A mcb off for a few days to isolate power to the sunhouse and the equipment in there?
6. What white goods do you have ie washer, dryer, dishwasher and microwave? Have these changed recently?
7. Do you have an induction hob?
8. Have you had a smart meter fitted recently or at all?
9. Do your lights ever flicker? Do your neighbours ever?
10. Has any digging been done in the garden near the cable to the sunhouse?
11. Have you had any water leaks or rain water ingress to your home of sunhouse?
12. Who did the electricity supply to the sunhouse? Do you have a test certificate if it was done after the main house? How long is the cable run?
13. Would you say the problem never happened until the shift of equipment to the sunhouse?
14. Do you have an electric vehicle charger?
15. What exactly is fed by each circuit breaker - a labelled picture would be helpful.
16. Do you have air conditioning units or heat pumps?
17. Please post a picture of your supply intake and meter.

My hypothesis is you have a loose line, neutral or earth connection(s) - within or without your property - which is causing high dV/dt of the supply voltage; a or several connected loads have mains filters within them which are reacting to the high dV/dt with a high albeit brief current as their capacitors change their state of charge. I suspect the circuit for the sunhouse since it has used unusually split concentric cable which needs care terminating well. The reliable conduction of a connection or joint can vary with current density.
Hello mate first of all thanks for taking the time to write all that!
So I’m unsure on my PSU model I will find out tonight
2.
Hello. Please would you tell me:

1. The make, model and power of your gaming PSU. Do you have more than one?
2. Do you plug them directly into a socket or via a surge suppression socket strip?
3. When you say nothing is on do you mean the PC, IT and gaming equipment including PSU is switched off on the equipment or at the socket?
4. Co-incident with moving the equipment to the sunhouse have you added any equipment or changed any of it?
5. Have you tried leaving the 40A mcb off for a few days to isolate power to the sunhouse and the equipment in there?
6. What white goods do you have ie washer, dryer, dishwasher and microwave? Have these changed recently?
7. Do you have an induction hob?
8. Have you had a smart meter fitted recently or at all?
9. Do your lights ever flicker? Do your neighbours ever?
10. Has any digging been done in the garden near the cable to the sunhouse?
11. Have you had any water leaks or rain water ingress to your home of sunhouse?
12. Who did the electricity supply to the sunhouse? Do you have a test certificate if it was done after the main house? How long is the cable run?
13. Would you say the problem never happened until the shift of equipment to the sunhouse?
14. Do you have an electric vehicle charger?
15. What exactly is fed by each circuit breaker - a labelled picture would be helpful.
16. Do you have air conditioning units or heat pumps?
17. Please post a picture of your supply intake and meter.

My hypothesis is you have a loose line, neutral or earth connection(s) - within or without your property - which is causing high dV/dt of the supply voltage; a or several connected loads have mains filters within them which are reacting to the high dV/dt with a high albeit brief current as their capacitors change their state of charge. I suspect the circuit for the sunhouse since it has used unusually split concentric cable which needs care terminating well. The reliable conduction of a connection or joint can vary with current density.
I will put my pc details in the chat for you to see sir! First of all thanks for taking the time to write all that.
1. See picture
2. It is all plugged in via a surge suppression strip, i have only changed that as of a couple of days ago and the issue is still happening.
3.I leave my PC and everything plugged in and turned on at the socket.
4. My PC has never tripped the inside circuits of my house before, The garage in the past has been found with the MCB off but never this much.
5. I havent left it off for more than a day no.
6. Yeah we have all of the above but no they have not been touched since we moved in.
7. We have a Gas hob
8. We have a smart meter just plugged into the sockets in the kitchen, we have recently plugged it back in a few weeks ago, however i unplugged it again to see if it was causing the issue and it appears to not have had any effect as its still tripping.
9.Not that i know off.
10. No digging has been done since we moved in,
11.No water that i can tell.
12.Its definitely gotten worse since the equipment was moved in, But we have used the sun house a lot in the past and i must say it was rarely off but it has happened.
13.Not never happened just happening a lot more now.
14. NO
15. The 40A one in the picture is the garage one but ill get a laballed pictuire.
16.No
17. I will get those photos.

Thanks hope that helps please ask any more questions that you want to. I appreciate the help!


Also i redone the IR test and took the dodgy outside light down and its still tripping. The IR test again came back perfect.
 
Hello. Please would you tell me:

1. The make, model and power of your gaming PSU. Do you have more than one?
2. Do you plug them directly into a socket or via a surge suppression socket strip?
3. When you say nothing is on do you mean the PC, IT and gaming equipment including PSU is switched off on the equipment or at the socket?
4. Co-incident with moving the equipment to the sunhouse have you added any equipment or changed any of it?
5. Have you tried leaving the 40A mcb off for a few days to isolate power to the sunhouse and the equipment in there?
6. What white goods do you have ie washer, dryer, dishwasher and microwave? Have these changed recently?
7. Do you have an induction hob?
8. Have you had a smart meter fitted recently or at all?
9. Do your lights ever flicker? Do your neighbours ever?
10. Has any digging been done in the garden near the cable to the sunhouse?
11. Have you had any water leaks or rain water ingress to your home of sunhouse?
12. Who did the electricity supply to the sunhouse? Do you have a test certificate if it was done after the main house? How long is the cable run?
13. Would you say the problem never happened until the shift of equipment to the sunhouse?
14. Do you have an electric vehicle charger?
15. What exactly is fed by each circuit breaker - a labelled picture would be helpful.
16. Do you have air conditioning units or heat pumps?
17. Please post a picture of your supply intake and meter.

My hypothesis is you have a loose line, neutral or earth connection(s) - within or without your property - which is causing high dV/dt of the supply voltage; a or several connected loads have mains filters within them which are reacting to the high dV/dt with a high albeit brief current as their capacitors change their state of charge. I suspect the circuit for the sunhouse since it has used unusually split concentric cable which needs care terminating well. The reliable conduction of a connection or joint can vary with current density.
 

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Thank you.

For now it would be helpful if you opened up each CU (House and sun house) and with power off carefully inspect where the lower terminals of mcbs connect to busbar to confirm they are clamping or being screwed onto busbar. Tighten up all lower mcb screws and note down any which appeared loose. Do the same for RCDs and mains switches

Check solidity and security of neutral and cpc connections by tug and wiggle check. Again note any loose ones and tighten up. While you are at it remake the neutrals for the split concentric at the house CU.

With all sunhouse IT and gaming powered up go to intake and meter board and gently wiggle - not tug - the tails and feeds. Any trips?

Is the surge socket strip a simple type with a glowing neon or is it a professional one which contains inductors, capacitors and over voltage protection Eg by Olson?

Try plugging your sunhouse IT and gaming equipment directly into mains instead of via the surge socket strip. Leave for say a few days or until another mob trip happens.

Try leaving your IT and gaming equipment unplugged from mains for a few days or until trip happens.

Try turning off main switch of sunhouse CU but house 40A mob on for a few days or until trip happens.

What is the answer to 12 please? I will not give you a hard time if it was you.

Probably enough for now.🙂
 
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Thank you.

For now it would be helpful if you opened up each CU (House and sun house) and with power off carefully inspect where the lower terminals of mcbs connect to busbar to confirm they are clamping or being screwed onto busbar. Tighten up all lower mcb screws and note down any which appeared loose. Do the same for RCDs and mains switches

Check solidity and security of neutral and cpc connections by tug and wiggle check. Again note any loose ones and tighten up. While you are at it remake the neutrals for the split concentric at the house CU.

With all sunhouse IT and gaming powered up go to intake and meter board and gently wiggle - not tug - the tails and feeds. Any trips?

Is the surge socket strip a simple type with a glowing neon or is it a professional one which contains inductors, capacitors and over voltage protection Eg by Olson?

Try plugging your sunhouse IT and gaming equipment directly into mains instead of via the surge socket strip. Leave for say a few days or until another mob trip happens.

Try leaving your IT and gaming equipment unplugged from mains for a few days or until trip happens.

Try turning off main switch of sunhouse CU but house 40A mob on for a few days or until trip happens.

What is the answer to 12 please? I will not give you a hard time if it was you.

Probably enough for now.🙂
Ok mate i will do as you say at some point today and come back with results!

The surge protection strip is LOGIK which i think is just a standard one of the shelf electrical wholesalers.

I will try and see if the error occurs when nothing is plugged into the sunhouse, Can a bad PC power unit cause things like this to happen?

So the cable to the sunhouse i know little about as it was all here when we moved in. The sun house is an extension of the old garage so i imagine the its the original cable from when the whole place was built. I have considered wiring a temp 6mm SWA from my DB to the garage. To see if the duct or something is crushing the cable underground where i cant see but surely any issues would show up on the testing i have done?

Again thanks for taking the time i will get back to you later today :)
 
High performance high power Pc and gaming power supplies do not last forever. They contain capacitors which are worked hard and run hot which reduces their life. One might expect 20000 hours life from the PSU but considerably less if the PSu is left on all the time. One sign of failing capacitors is mcb tripping. How old are your power supplies and do you leave them powered up all the time? Mcbs often trip faster than fuses rupture.
This is why some time with your equipment unplugged would be helpful.

what is the ambient temperature like in your sunhouse? Does it get quite warm at times or has it in the past ie over say 18-21C? Are the fans working and any filters clear of dust And unobstructed? Check there is good air flow around PSus and that one does not suck in the hot air from the other.

Last, these sort of power supplies have high inrush current when turned on. The value depends on where in the mains cycle they are energised and the state and polarity of charge on the capacitor. If there was a loose connection then it could be inrush current is tripping the mcb.
 
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It might be worth ruling out faulty breakers.The 40amp one could be very sensitive and the others that trip randomly could be going the same way.Maybe worth swapping out the 40amp breaker for a new one to see if that cures it?
 

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