Finland Electrics dilemma. MCB trip... weak or bad wiring?

[dhChewy]

Hey all,

This will be a lengthy OP, but I'm trying to get as much information out as possible to get the trimmings away from the meat of the problem. I'm a straight-up novice in the electrical department, even though my brother is an electrical engineer-- he lives back in Los Angeles, and I've moved to Finland years ago.

The disaster:
MCB (mini circuit breaker) randomly tripped a few nights ago while family and I were playing video games.

The QUESTION:
Could I have bad wiring somewhere in my flat? Or am I dealing with two separate issues (described below)? I don't even know what I'm looking for anymore... I just want to know what's going on.

Some back story and other things that may or may not be related:
I purchased an audio receiver a couple months ago, installed it, and that's when the electrical circus show began. While the TV was on, if someone switched OFF the bathroom lights, there was a 30% chance the TV input signal would drop out for a second. I didn't (and still don't) know what the severity of this issue would cause in the long run, so I didn't pay it any attention. There was also rare cases where if the stove top light (fluorescent) was turned off, or the microwave was turned off, the TV input signal was also affected. The TV flickering was never an issue before the audio receiver was installed, so I assumed it was the culprit.

Fast forward to a few nights ago:
When the MCB tripped, my wife and I had to manually search for the appliance that wouldn't allow us to reset the switch. We found it was the computer's PSU. We tested it out by plugging the PSU into the outlet, only to trip the MCB again. So we left the computer unplugged (the MCB trip killed the PSU and my new motherboard icon_sad.gif ). We figure it could have been an overload on the MCB, but we had been running fine for the two months we've had the audio receiver installed-- so what could have pushed it?

We had our building's handyman give his opinion, and he blamed it on HDMI cables. He said our cheap quality HDMI cables are the cause of the TV flickering (likely due to the fluorescent tube in our bathroom) and could have shorted, causing the MCB to trip. He also mentioned it could have been an overloaded circuit line.

Giving him some respect, I decided to test all of my HDMI cables. Of the 13 cables I've tested, 11 cables reacted to the light switch test (turning off the bathroom light). I highly doubt all of my cables are THAT bad to cause an MCB to trip randomly. Hell, millions of the same quality cables are being used around the world these days... so why isn't everyone experiencing the same issues as I am?

So I took my new audio receiver to the nearest credited service center to get inspected, came home to do some more tests and found something more mind boggling. The light switch STILL caused temporary input loss on the TV... except, now it also occurred when the lights were turned ON. So now, I figure I should also test the load on the circuit line. I unplug all my appliances, leaving only the TV, an Xbox, and our internet modem connected to the line. I hit the light switch on and off, and TV input is interrupted again.

Now, I assumed it had to do with the fluorescent lighting as a few Google searches have turned up some similar problems. So I did some further testing, this time on two different circuit lines to see if it is a over-the-air proximity issue. I tested on my plasma HDTV, and LCD computer monitor, making sure it's not an isolated problem on just the TV.

Just a quick layout of the circuit lines in this flat. The affected line that tripped the MCB is connected to our entrance hallway, bathroom, living room, dining room, and kitchen. Hell of a lot of crap to be on ONE line. There is also four GFCI breakers lined up beside it (1,2,3,4)... with #4 connected to affected MCB somehow.
[GFCI 1][GFCI 2][GFCI 3][GFCI 4][MCB]

So here's the quick test:

1) TV/monitor connected to affected line, Xbox connected to unaffected line = the TV input is affected by light switch on/off.

2) TV/monitor connected to unaffected line, Xbox connected to affected line = the TV input is UNaffected by light switch on/off.

Does that mean the affected line needs to be inspected by an electrician, or can I troubleshoot further in hopes of getting this solved? Or are the TV interference a completely different issue than the MCB tripping? It just seems like they're related because the issues didn't begin until I installed the audio receiver.

My brother said it could be anything from broken wires, loose wire nut, loose connection, or bad fluorescent ballast powering the bathroom tube. I'm down to inspect things out myself, but I'm quite clueless to the whole electric arena. I only started reading up on these things the past couple days. I took a multimeter to all of the outlets on the affected line: VAC all within range (225v), resistance all at 0. I haven't metered at the breaker yet-- is it something I could do or should do?

Any and all help is greatly appreciated. If you need pictures of circuit unit or more info, let me know.

PS
I'm not quite sure how the L, N, and E all work out here. The outlets used are like Germany's, Schuko (Type F, CEE 7/4), where the two plug holes can be interchanged when a plug is inserted-- i.e. no fixed negative or live port, but earth is fixed... wiki image for reference:

 

[bernardgreen]

MCB trip when excessive current is flowing.

GFCI ( Ground Fault Circuit Interruptor ) operate when there is a fault that involves current flow to ground. Normally this has to be about 20 to 30 milliamps before the GFCI will trip.

For UK readers the GFCI ( USA name ) is very similar to the UK RCD

Most power supplies for computers, audio visual and similar equipment have mains filters in them and these filters do create a small current to ground, per item the current is too small to trip the GFCI. But if there are several such power supplies in use ( or just on standby ) then the total current to ground may be enough to trip the GFCI

The mains filter in the "audio receiver" may have added the last bit of ground current needed to trip the GFCI

 

[dhChewy]

@bernardgreen

Thanks for the reply. Would you happen to know why it took a couple months before the mcb would trip so badly as to blow out my computer psu? That's something I'm having a difficult time understanding, and wondering if the AV receiver installation exposed something that had already existed? i.e. unstable/weak connection, bad wires, etc.

 

[winston1]

HDMI cables do not cause MCBs to trip. Some cause TV interference, but price is no guarantee of quality. Some of the best ones are sold in one pound shops in the UK.

TV losing signal when lights are switched is due to RF interference generated by the spark at switching. Cure is better aerial installation and better screened coax cable.

Your MCB tripping is a separate issue.

 

[dhChewy]

TV losing signal when lights are switched is due to RF interference generated by the spark at switching. Cure is better aerial installation and better screened coax cable.

Could RF interference travel through cabling/lines? I assumed that was an issue OTA? I've already tested where I connected the TV or PC monitor to an unaffected circuit line in a bedroom with an extension cable, placed the unit right in front of the bathroom, flicked the light switch multiple times... and no interference. When I placed the monitor clear across the room, away from the bathroom and into the dining room, though it was connected to another outlet on the same affected circuit line, the interference would reappear.

I don't have any analog or coaxial connections. With the av receiver, I had 4 HDMI input devices plugged into it, and one HDMI output from receiver to TV. (3 gaming consoles, 1 htpc all connected via HDMI to AV receiver, and output to plasma HDTV). Without the receiver, it was a direct connection between device and TV via HDMI. (1-to-1 because the TV only has one HDMI-In port). No matter the setup, they all flickered when the light switch was hit. I'll try testing with composite/component/ or DVI later today after work and will give results shortly after.

 

[bernardgreen]

Are you sure it is the MCB ( over current ) device that is tripping and not the GFCI that is tripping ?

If the TV signal is digital then a voltage disruption on the mains can distort the received TV signal enough to cause the TV decoders to loose synchronisation with the incoming signal. This will cause loss ( or freeze ) of the picture until the decoder has been able to re-synch with the signal.

Switching items on and off can cause voltage disruptions on the mains supply. Almost all devices have a brief inrush current that will dip the voltage for a short time ( less than half a second ) Some energy saving lamps have a high in-rush current.

 

[dhChewy]

Are you sure it is the MCB ( over current ) device that is tripping and not the GFCI that is tripping ?

I'm most likely wrong on labeling the other switches as being GFCI, but the MCB (miniature circuit breaker) switch is definitely the one that tripped. Here's a picture of our actual panel. What I assume are GFCI switches are the three bigger ones that are black/yellow.

Untitled

• dhChewy
• 15 Dec 2014
• 1

And here is a closer image of the mcb I'm talking about.

Untitled

• dhChewy
• 15 Dec 2014
• 1

The bigger switch beside it seems to be connected on the same circuit line for my lights and some outlets, though that one didn't trip, just the one I pointed out.

If the TV signal is digital then a voltage disruption on the mains can distort the received TV signal enough to cause the TV decoders to loose synchronisation with the incoming signal. This will cause loss ( or freeze ) of the picture until the decoder has been able to re-synch with the signal.

I want to believe that this is the cause, but why did it only start to happen just 2 months ago? I've never experienced it the five years I've lived here until now. Before the receiver, I had a soundbar, and everything seemed fine. I'd blame the receiver for possibly disrupting the voltage, but right now, I don't have it installed, and the interference is still ongoing. What changed in the two months of installing the receiver that the TV does it pretty much all the time now? I had a cheap Chinese [3-In, 1-out] HDMI switch from ebay before the using the receiver, and there weren't any digital interference then. Again, I'd blame the receiver, but I just heard back from the Yamaha service center that's inspecting my receiver, and they said it's fine. They did, however, assume I may have a bad ground or wire hanging by a strand somewhere.

Switching items on and off can cause voltage disruptions on the mains supply. Almost all devices have a brief inrush current that will dip the voltage for a short time ( less than half a second ) Some energy saving lamps have a high in-rush current.

I'm fresh out of incandescent bulbs, but will try this in the coming days. Could the bathroom fluorescent fixture be faulty/ or dying? I tried flipping some other lights on and off, also on the same circuit line, and maybe only once, did the TV drop picture for a split second (the light source was one of three other energy-saving lamps on the line).

As for updates on different input cables, I've tried RCA/SCART, which didn't have an effect when hitting the light switch. Haven't tried component or DVI yet... I've gotta find them first.

And I'm still lost at what actually tripped the breaker.