audio-talk

Hi all,

Nothing to do with hi-fi I'm afraid but I know some of you have good knowledge in this area. Today the house RCD began tripping out again on the sockets. We'd reset it, and about 10 - 15 minutes later it would go down again. The same thing started happening around last November / December, and I thought we'd isolated it to either my Active Diamonds or the multi-way strip I was using. After removing both, there were absolutely no further issues at all until today.

Currently I'm running what tests I can - I've flipped the breaker for the 2nd floor sockets and things seem to be stable - suggesting either a wiring issue or one of the appliances up there, but I just can't make any sense of the fault modes. The most frustrating aspect is the intermittent nature of it, and the fact that one RCD covers the whole damned house, it's like trying to find a needle in a haystack.

I know it's possible to get plug-in RCD's - do we know if these are more sensitive than a typical consumer unit RCD? Basically if a faulty device is plugged into it, I want it to reliably and consistently trip out before the one in the consumer unit brings down the whole house. This way I at least have a chance of narrowing down what's causing this.

Or would an isolating transformer with an RCD on the secondary work? I just want something that'll help me identify where the problem is. I work remotely and cannot have the electricity constantly failing like this.

All ideas gratefully received.

I had a similar problem a short while ago.

A mouse had nibbled some twin & earth.

There were times when the cable was "sizzling" but not tripping the circuit breaker.

Is there something on the circuit that activates itself at undefined times? The issue i had with the breaker tripping intermittently was the fridge freezer, it comes on when it wants to rather than a set time. At least it tripped the rcd for the kitchen sockets so i had a defined area to look at rather than a whole house

Perhaps something like this might find the problem?
https://www.tnt-audio.com/accessories/h ... 07d_e.html

I had a painful spell diagnosing a fault like this, 2 years ago. It was the fridge but only when it went on its defrost cycle.

Ant wrote: ↑Sat Feb 19, 2022 3:51 pm Is there something on the circuit that activates itself at undefined times? The issue i had with the breaker tripping intermittently was the fridge freezer, it comes on when it wants to rather than a set time. At least it tripped the rcd for the kitchen sockets so i had a defined area to look at rather than a whole house

Not to my knowledge - we think the issue is on the 2nd floor where the offices and all the computers and stuff are. The problem seems to go away when we unplug everything up there, but the fault behaviour has given us conflicting messages about whether the issue is in my office or in Meredith's. Although I've since discovered (after flipping the MCB marked 2nd Floor sockets to try and isolate the problem) that two of the living room sockets, on the 1st floor, are wired into the 2nd floor ring. So it seems my 300B power amplifiers have been sharing a ring with a PC, a Mac, and all the ancilliaries and router equipment, and the preamps and stuff are on the 1st floor ring. Those input isolating transformers are working well cos that would be a hell of a ground loop otherwise.

Why only one RCD for ALL the fucking sockets in the house? How the hell are you supposed to track issues down? The temptation to wedge the sodding thing closed with a screwdriver is overwhelming, but yes I know it's there for our safety and prevents shocks and fires and shit, and yes it would invalidate my house insurance so of course I'm not going to do it, but this is utterly maddening.

Richard Higgins wrote: ↑Sat Feb 19, 2022 5:34 pm Perhaps something like this might find the problem?
https://www.tnt-audio.com/accessories/h ... 07d_e.html

Thanks Richard - I might just pull the trigger on one of those.

IslandPink wrote: ↑Sat Feb 19, 2022 6:43 pm I had a painful spell diagnosing a fault like this, 2 years ago. It was the fridge but only when it went on its defrost cycle.

This has come up a lot in Google searches - that it most commonly seems to be white goods that cause the issue. We did recently take delivery of a new fridge where you don't have to defrost the freezer, so it must have a similar cycle, and mostly these issues occurred after the new fridge arrived - but there was one occurrence before then, but that time I only needed to reset the breaker and all was well.

I suppose if it happens again, I could try isolating the circuit with the fridges on before resetting the RCD and see if that makes any difference.

I have the cooker and two sockets next to it that are on a different loop to the normal fridge socket. I used an extension lead to run the fridge off the other socket until something happened.

So this is interesting. When this happened last year, I remember commenting about it on here, so I was able to discover the date and time - December 7th around midday.

When it happened today, it had been raining quite a bit with a strong westerly. The nearest point to here that I could find historic weather data for is Southampton Airport which is some miles down the road, but it seems that it was raining on the south coast quite a bit on that day. I have a vague memory of it being wet outside when we were charging around the house trying to debug the issue last time.

So I'm wondering now whether water ingress might be a factor here. Would make sense if it's the top floor sockets being affected.

Edit: I think it might be time to call in the experts - the roof needs looking at anyway as Eunice took off two or three tiles, and we'll get a sparky in to do some tests. The system was EICR tested last year and given a clean bill of health.

I think it might also be time to get some UPS's for the computers, as it's not doing them any good being powered off at random like this. Good way to get flat spots on the Garrard's idler wheel too.

so, not quite enough information to help you. Is youre whole house protection rcd because you have a TT earthing system so it is a 100mA rcd. Or to you have either a pme or cable sheeth earth but with a very badly thought out consumer unit with one single 30mA rcd controlling everything. In such a situation you could put as standard power switch and mcbo’s in place of every mcb.

You shouldnt have two sources for the sockets in the same zone, by the way. If I were you the least you should do is stick a warning label on the sockets and in the consumer unit.

As for the cause of the breaking. Get an electrician to test all youre circuits first. Probably a faukty rf supressor in youre computer equipemnt, microwave, fridge freeser, washing machine. caps and or spike supressors give leakage beyond the 30mA permitted in a heavily stocked computer type environment, where there is a lot of earth current but also in failure mode loads of imbalanced phase/neutral current imbalance, that area should definately be on its own rcd. The rcd itself would get a ramp test to see exactly what current imbalance it trips at. Might just need a new one.

Dont be like my father in law, ignored a faulty socket in his bedroom. Never mentioned it to me. His bungallow burned down while he was sat at the table having his supper, the toxic smoke inhalation killed him, we know from the autopsy, and from the policeman who first to attend crawling in on his belly saw father in law black as a chimney sweep sat having his supper.

Get a full scope electrician (which I was) to test youre house.

Dave
if you want to know what the weather was doing on your doorstep there will doubtless be a weather station nearby:

each of the green circles is a weather station...if you go to the website shown you can manipulate the map to show the nearest green circle to you and click on it..from there you can find the history of the weather at that station....

https://www.wunderground.com/dashboard/pws/IEASTL18

Paul Barker wrote: ↑Sun Feb 20, 2022 8:55 am so, not quite enough information to help you. Is youre whole house protection rcd because you have a TT earthing system so it is a 100mA rcd. Or to you have either a pme or cable sheeth earth but with a very badly thought out consumer unit with one single 30mA rcd controlling everything. In such a situation you could put as standard power switch and mcbo’s in place of every mcb.

You shouldnt have two sources for the sockets in the same zone, by the way. If I were you the least you should do is stick a warning label on the sockets and in the consumer unit.

As for the cause of the breaking. Get an electrician to test all youre circuits first. Probably a faukty rf supressor in youre computer equipemnt, microwave, fridge freeser, washing machine. caps and or spike supressors give leakage beyond the 30mA permitted in a heavily stocked computer type environment, where there is a lot of earth current but also in failure mode loads of imbalanced phase/neutral current imbalance, that area should definately be on its own rcd. The rcd itself would get a ramp test to see exactly what current imbalance it trips at. Might just need a new one.

Dont be like my father in law, ignored a faulty socket in his bedroom. Never mentioned it to me. His bungallow burned down while he was sat at the table having his supper, the toxic smoke inhalation killed him, we know from the autopsy, and from the policeman who first to attend crawling in on his belly saw father in law black as a chimney sweep sat having his supper.

Get a full scope electrician (which I was) to test youre house.

Thanks for the input Paul, much appreciated. We only discovered those sockets were on the different zone after I'd isolated the 2nd floor sockets with the MCB but turned everything else back on. Wondering why we still had no wifi or internet, found that the socket in the living room with all the router equipment was still off. Rerouted the power to those, but then found when switching on the hifi in the evening that the amps didn't come on - indicating a second socket was also on the zone I'd isolated. I'll put some labels on them as per your advice.

And yes, it's one RCD covering everything except the lighting - I presume there must be a separate one for that. Reconfiguring the consumer unit to have the protection more granular would certainly help matters.

I'll be taking time out later today to do some phoning around - we need a sparky, along with a fence repairer and roofing specialist after these bloody storms.

Paul Barker wrote: ↑Sun Feb 20, 2022 8:55 am so, not quite enough information to help you. Is youre whole house protection rcd because you have a TT earthing system so it is a 100mA rcd. Or to you have either a pme or cable sheeth earth but with a very badly thought out consumer unit with one single 30mA rcd controlling everything. In such a situation you could put as standard power switch and mcbo’s in place of every mcb.

Hi Paul - here's our consumer unit. The one I have to keep resetting is immediately to the right of the four MCB's with the green sticker underneath. I see it's marked 30mA so it sounds like the latter in your description. It's a three storey property and just to add to the fun you'll see we have solar panels (far left). Probably want to open the picture in a new window for better resolution.

Edit - I'm rather mystified by what is covering "Lights First Floor", and why it looks like something other than an MCB. The red stickers denote 'circuits not RCD protected' yet it looks remarkably like an RCD to me. Maybe it's for the 2nd floor bathroom power shower, which would mean that 1st floor is actually second floor. Before you completely flip out, the shower doesn't have any heating elements in it as it has hot and cold feed, just a pump to increase the water pressure.

Normal looking for 16th edition. You dont have whole house protection and you dont have TT earth (which is good because earth fault impedance on TT is 100ohm sometimes more, meaning more chance of you carrying fault current.)

You need youre insulation resistance testing, and figure of 8 ring main checks, especially since you already discovered two fuses to isolate one zone. When that sort of work has been done you might have out of reach and out of sight mechanical connections which are no longer allowed, but was allowed in 16th era. So a connection could be arking (50hz oscilation lostens the screws). Yes its often white goods but bad connections out of view and rodent munching pvc in inaccessible places unknown burn houses down.

Thats why these days all screw connections should be in a visible switch or socket, because everyone associates those with electricity, and if they are making a buzz or arking noise or if when they put a plug in a socket its intermittent, they might have enough sense to call a competent person to investigate. But in youre case youre not protected by that updated safer way of wiring a house.

Once this is over, the fault is found, you could have individual rcbo’s (they give over current protection AND phase/neutral current imbalance protection) on the right side of distribution board you pictured, and you have whole house protection.

But unseen dangers under youre floors especially with the dodgy work we already expect is under there from two sources in one zone. a spur of something not fused for example, and from a different zone. It doesnt look likely from youre consumer unit, but its not uncommon to find two phases in the same zone and thats VERY BAD. But that is most unlikely unless its a converted pub or someone stole electricity from neighbours before your time in the house. Neighbours not guaranteed on same phase out of the 3 going down youre street.

If you could lend a thermal image camera which isnt a fortune these days, you may see the issue thermally. Put a good load on the circuit one at a time and try see if any hot spots. Another way to trace cables out of view is using rf. you transmit rf on the phase in question and ground then you go with a “sniffer” which pics up rf following loudest signal. There are gadjets for it that arent over expensive. Any radio ham could make you a simple one. I had one and it was imensely valuable. But my lockup is huge and piled up, and I dropped electrical work soon after the era youre house was most recently worked on by an electrician from youre consumer unit style. Chances of finding it and in good condition, since the batteries will have acid etched it.