Dirty mains power breaking my gear!

[maskedwarrior]

Hello all. Long time since I last posted in this this great forum. I have a question about Surge protectors, power conditioners, UPSs or similar.

I live in SW England, in a very small town in an old commercial bank building which I suspect has some dodgy wiring (the lights and plugs for three and a half rooms all appear to be on one circuit, the bathroom light had a 13 amp fuse in it, and turning the oven off trips the RCD occasionally. None of which I feel bodes well).

My PCs and speakers have also been breaking with depressing regularly and, with the most recent casualty being my main work PC, I'm now convinced this can't be a coincidence.

I rent this property, but nevertheless I'm prepared to pay for an electrician to come look at my mains. Perhaps the AC sine wave is distorting, perhaps it's a faulty appliance plugged in elsewhere, perhaps it's 'brown outs' or spikes? TBH electrical appliances do tend to run noisily here.

I am no electrician. Perhaps it isn't a power issue, perhaps it's just bad luck. But even so, it never hurts to play it safe or be armed with some solid advice.

So two questions:

1. Can anyone recommend any professionally-rated products or solutions to make sure my mains power to sensitive equipment is reliable and stable?
   
   Solutions in the hundreds of pounds preferred, rather than thousands.
   
   (A list of approved products might be useful for anyone setting up an ad hoc studio or running sensitive equipment in less-than-ideal environments.)
   
   -
2. Can anyone give tips on what I should ask an electrician to look for, or what equipment they should use, to best diagnose any mains power issues?

Thanks very much in advance,
Tony

[Drew Stephenson]

I'd hesitate looking for any extra kit until you've had a proper electrical inspection. Power supply in the UK should be fine without anything additional in the loop.

[DGL.]

Adding to this some older houses were wired with a ring upstairs and spurs to each of the downstairs sockets (like my Grans place), so only having one ring, whilst undesirable, should cause "dirty power".

[maskedwarrior]

I'd hesitate looking for any extra kit until you've had a proper electrical inspection.

Thanks for your response. Of course. Have no fear, I will not rush out and buy anything if we discuss some hypotheticals. XD

Also the sparky has told me he may not catch the problem while he's here, if it's intermittent.

I mean, perhaps there aren't any hypothetical solutions/products because this problem never comes up in the real world, therefore no easy solutions/products exist, therefore we can't discuss them?

That could be so, I don't know. I assumed there was gear out there that might help eliminate dirty power as a possible cause.

Adding to this some older houses were wired with a ring upstairs and spurs to each of the downstairs sockets

Thanks fir your response. That's interesting to note and reassuring. No doubt the electrician will tell me if that's a problem.

However, until he arrives, I'm bearing in mind that: this was built as a commercial property, not a house. It's a ground floor flat, with one flat above. There are the remains of electrical conduit all over the walls, encircling a safe structure which is too dense to drill through without extra trouble. There is other evidence of electrical problems/sloppy work.

Hence why I ask for possible gear/solutions to fix a power issue, so I can learn more and be prepared, to help rule this out as an issue.

I honestly can't think of any other reason I've experienced so many weird issues with PCs, monitors and speakers going wrong lately, short of some supernatural element. XD

Tony

[Wonks]

You're much better off getting any problem sorted at source if possible.

I'm not sure if a standard electrician would have access to a mains analyser, which will tell you about %THD of distortion on the mains as it should be as close to a sine wave as possible. Ideally that's the sort of thing you'd start with, as well as checking mains voltages are within tolerance and the basic wiring installation is sound and there's a good earth and live and neutral aren't crossed etc.

But as you say it's a basically commercial building, there may be other equipment within the building that occasionally puts out big spikes. You might be on a different feed at the main building distribution board, but until you get back to a transformer, any spike from elsewhere in the building on the same phase can backfeed into your flat's electrical system.

But you may just have a collection of local issues, such as non-regulation electrical wiring (not allowed as far as I know for rented property), and a possibly faulty cooker etc.

[maskedwarrior]

You're much better off getting any problem sorted at source if possible.

Thanks for this helpful reply!

I agree. Although I feel it may be a long and potentially fruitless battle with my landlord to get this property rewired and, in the mean time (or for as long as I rent this place), some sort of surge protection device or other fix might allow me to continue working without constant malfunctions!

But you may just have a collection of local issues, such as non-regulation electrical wiring (not allowed as far as I know for rented property), and a possibly faulty cooker etc.

Indeed! You might be right. May I ask, when you say 'non-regulation wiring' are you referring specifically to anything I've mentioned or are you speaking more generally/hypothetically?

Thanks, Tony

[Martin Walker]

But as you say it's a basically commercial building, there may be other equipment within the building that occasionally puts out big spikes. You might be on a different feed at the main building distribution board, but until you get back to a transformer, any spike from elsewhere in the building on the same phase can backfeed into your flat's electrical system.

I too live in the SW in a small village, and five miles away is the Delabole Slate quarry, where there are heavy duty machines cutting and polishing the slate. I suspect this is the main reason why I notice noise on my mains supply which is worse at some times than others (it manifests as a slight acoustic buzz on my power amp transformer). The waveform below is about the worst I've monitored:

In my first job (many, many years ago) I worked in a factory where the weekly pay packets were distributed on a Thursday, so no-one worked overtime on a Thursday evening. Now it may be total coincidence, but I've regularly noticed the 'best' sound I get from my current studio is on a Thursday evening - this is the more typical waveform (not a perfect sinewave by any means, but a hell of a lot better than the previous one!)

This is what Wonks means by %THD on the mains waveform, and it's not really within a typical electrician's remit.

Martin

[Hugh Robjohns]

Firstly, if you're renting, the landlord has to have an electrical safety inspection every five years, and should make the report available to you. So that should rule out non-compliant wiring in the premises.

https://www.gov.uk/government/publicati ... ted-sector

If the incoming mains was on the very high side of the permitted range it could cause problems. A simple plug-in mains power analyser will tell you the incoming mains voltage (amongst other things). Eg.

https://www.amazon.co.uk/Monitor-Backli ... C64&sr=8-6

If you're getting spikes surge-surpressing plugboards might help... for a while. However, most rely on MOVs to catch the spikes and they 'wear out' with repeated activity, so you end up without any protection and no way of knowing what state the MOV is in!

If you have a dirty mains supply the only real way to ensure clean mains is to use an 'online' UPS which charges a battery from the mains, and then generates an independent clean sine-wave mains supply from the battery.

The UPS will also provide cover for brown and blackouts too, of course -- the backup duration depending on the size (capacity) of the unit's battery and the power consumption of whatever is plugged in to the UPS.

I've used a couple of chunky APC units for years to power all my computer and network gear, as well as my digital console and other sensitive stuff as I get a lot of brown outs here.

The downside is that a good quality online UPS is going to cost more than a hundred or two.... but it is the only guaranteed solution and is a long term investment.

[n o i s e f l e ur]

I've used a couple of chunky APC units for years to power all my computer and network gear, as well as my digital console and other sensitive stuff as I get a lot of brown outs here.

You must be imagining this Hugh, as I've been informed on these fora that This Kind Of Thing just doesn't occur in the U.K.

Anyway . . . nevermind all that. What we really need are professional standards and credentials for condescension, jingoism . . . and perhaps parochialism? I'm game!

[ef37a]

Hugh has covered the points I was going to raise including the continuous converting PSU.

I do however think the power company should be involved here? You will likely have to do that through your landlord.

I recall a chap in a village here having problems with a VCR and he got the then Electricity Board to fit a voltage recorder to his supply. They found spikes over 1kV! They fixed that.

Dave.

[Hugh Robjohns]

You must be imagining this Hugh, as I've been informed on these fora that This Kind Of Thing just doesn't occur in the U.K.

You misunderstand. I dont use them to 'clean' dirty mains. I've never ever had a problem with dirty mains upsetting my recording equipment on location anywhere in the UK.

I use UPS boxes here because my village is powered via overhead lines and on windy days we get brown-outs and black-outs that upset the computers and network gear.

Mains power can certainly get 'bent' by some heavy industry nearby, as Martin's graphs clearly illustrate. But I wouldn't expect that kind of thing to cause devices to die. It shouldn't affect audio recording quality either, if equipment power supplies are well designed.

Big spikes can certainly kill things, though, as discussed.

[Jimmy B]

+1 to UPS.
That is how all of the data centres in the world work, and it is one of the reasons why Google is always there when you need it.

So when your thorough investigation has shown that the problem is someone else's fault, and that someone else has not been able to resolve the issue in a time frame that meets your needs, you may decide that the only solution is to throw money at it. At that point, a good UPS is the sure-fire solution.

One important parameter is the output waveform. Your PC may not care, but your audio equipment probably does:
https://www.kstar.com/indexproblem/17355.jhtml

[Folderol]

There is another technique that I've read about, but not seen in practice. It should work out as a good solution for just a bad supply (but won't deal with complete loss of power).
It uses in-line high speed switching components combined with filters, that can smooth the waveform as well as compensating for significant under and over voltage.

Sorry, no idea where you can get one or what the price would be.

[Jimmy B]

I just found this:

https://www.thomann.de/gb/furman_ac210_ ... tioner.htm

It isn't a UPS, but it doesn't have the size or cost of a UPS. It appears to combine a heavy duty surge suppressor with a relay to cut the power if it goes above 270 volts.

The target audience is gigging musicians who have no control over the environment where they have to play.

The theory seems plausible, if it's done well. Does anyone have any experience with one of these?

[ef37a]

I think it is worth pointing out that much of the problem with "dirty mains" is down to lack of adequate filtering in the audio equipment itself?

Way back in the day when most audio gear used valves we rarely had problems (but of course we had a nationalized electrical service).
Valves are rather immune on two fronts. Firstly, front ends were almost always triodes for lowest noise and rarely had a bandwidth much past 30kHz, often lower. Balanced inputs used transformers and these are magic for keeping RF out.

But the most effective 'crap stopper' IMHO was the socking great mains transformer. Not usually having an inter-winding screen in bog S kit like guitar amps but even so presented a fair old capacitance to any incoming noise. I would guess the more 'pro' preamps and mixers would have a screen?

The coming of the Silicon Planar Transistor gave even the most humble of kit a potential 100mHz bandwidth and it took manufacturers a very long time to get to grips with the problems that caused. Penny pinched SMPSU design also allows a good deal of muck through. We don't for example see very many posts with interference problems with say RME kit?

Dave.

[Hugh Robjohns]

The theory seems plausible, if it's done well. Does anyone have any experience with one of these?

No direct experience of it. However, it is definitely better than most standard surge suppressors in that it isn't 'sacrificial' and will continue to trap spikes after the first two or three!

Dunno how well it will clean up noisy mains. Probably does a reasonable job, though.

But obviously it can't help with brown-outs or total power interrupts.

[Folderol]

Halfway between plain suppression and a UPS would be a 1:1 inverter. I've seen this built into industrial kit, but don't know if it's available anywhere as a stand-alone unit.
This would deal with brownouts as well as spikes and overvoltage.