Hope someone can help with this?!?!

My parents have a rental property and the tennant is having issues with the electrical supply. It appears to be intermittantly dipping and turning certain types of electrical devices off but without tripping the power. It seems to be things which are modern and are left on most of the time, like TVs and internet routers etc. We've tried all manner of things like replacing the supply cable to the property, replacing the dis-board and RCD's. Still this problem persists. We've had some monitoring diagnostics done by Western Power and they seem to think there is some kind of low power device plugged in which may be causing the issue??

I'm a clanky and interpreting the following graphs is a little beyone my GCSE electronics training.

Does anyone see anything on these graphs which might explain the issue??

Thanks in anticipation.






[Edited on 9/11/20 by liam.mccaffrey]

First thing I notice are the spikes in AC Current.

I'd try and find out what is causing that - it may or may not be related but it's quite a large spike (5.5 Amps) and appears regularly. Seems to be every 40 minutes or so!

Do you know what's creating that??

It's happening at all hours and pretty regular

[Edited on 9/11/20 by JAG]

I'm afraid we've absolutely no idea, it's a little 1 bed apartment so there isn't a lot of heavy machinery hidden

my first guess would be fridge/freezer
edit
second guess would be central heating pump

[Edited on 9/11/20 by gremlin1234]

quote:

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Originally posted by gremlin1234
my first guess would be fridge/freezer

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Odd, I think you need to locate the source of those 5A peaks.

I would try logging the voltage with EVERY thing off in the house, log for say 3/5hrs and see if the peaks go. If not it's very odd - maybe something on the supply?

Like others have said freezer or fridge compressor might be a likely candidate.

Do you have an air source heat pump (AC or similar?) I guess they would have a very high inrush.

For electronics to re-set it must be a long outage?

Have you had the property electrics checked, might be some high resistance somewhere in the wiring?

Dan

[Edited on 9/11/20 by Bluemoon]

[Edited on 9/11/20 by Bluemoon]

To be honest, having monitored my own power for an issue of voltage drop at 8ish pm every night (lights dimming, but nothing powered off) I can say that plot surprises me greatly, especially if your supply line has been replaced. My voltage was stable to 2V across the day, regardless of a boatload of load and micro-generation on the property. The tolerance is 230 +/-6% so a really wide band, but your elec items are designed to run on that range, in theory. Which suggests it's another issue, such as EMI maybe, or dodgy wiring in the house.

Something on a timer - voltage dips stop at the same time on both graphs on different days, and for about 30 minutes every 6 hours (on the second chart)? This also corresponds with dips in the flicker reading. Can't think of anything normal that would do that.

The current spikes are once every 20 minutes during daytime and once every 30 minutes during the night. I don't think they are of long enough duration to be a heat pump/electrical heating/immersion, maybe fridge or freezer. They are not at the same time as the volt drops so may be unrelated, especially as you get 10% volt drops while only drawing 0.5 amps

Do you see the lights flickering?

What sort of heating has it got - is there an electric immersion heater with timer set at 12:30-1pm, 18:30 to 19:00, 00:30 to 1am by any chance?

Do the neighbours have the same issue? Is the house water supply provided by a well pump or similar

I'd isolate the power and tighten all the screws on every circuit in the fuseboard, but then I have done quite a bit of electrical stuff in the past, so you may not want to do that.

You could isolate the supply to one circuit at a time to see if it goes away for any particular one.

Best of luck
Hugh

Is the voltage not within the accepted tolerance?

"230V -6..+10%" and translates into 216.2..253V

I would say central heating related. Could the 10pm event be a shower. Failing bypass valve?

Could be a poltergeist

none of the spikes are big enough to be and electric shower, (and I think too big just to be a shower pump)
but I also notice there's just one spike at an extra 12/13 amps, - do they not use an electric kettle?

I'm quite interested in the 5 episodes of flicker. Using the timeline it might be possible to match these episodes with an appliance or event?

Given the definition of flicker, something relatively significant is going on during these epsisodes.

"The term flicker is often used to describe voltage fluctuations, especially when viewing graphs of RMS voltage trends that include fast, cycle-level variations. These fluctuations are typically caused by varying loads such as welders, arc furnaces and motor start currents. "

If nothing industrial is attached to the flat wiring, maybe something is earthing and the current is going to ground?

As a note, my father in law received a £9000 quarterly electric bill for his 1 bed flat as someone had tapped into his supply to run their "horticulture operation" in the adjacent flat. ........

It will be interesting to find the solution to this.

The tenants haven't got an old fashioned television have they 😃

Cheers
Ian

does the apartment building have a lift?

Thanks for the responses guys (and gals??)

Some additional information.

There are 3 small apartments adjacent to one another built in the mid to late 80s by my parents and using reputable contractors. Wiring has been checked recently by our electrician. (They haven't seen the graphs yet)

I believe each of the apartments uses a single phase of a 3 phase supply which supplied an industrial launderette in the 80s prior to the apartments being built.

The building has gas central heating but an electric shower. electric oven and hob. This has never been an issue in the previous 30 years. The other two apartments are not experiencing any issues. The TV is a modern 4k tv, there are no lifts.

Unfotunatley we don't have the capability to do ongoing monitoring, that was offered by the supplier when the cable replacement didn't solve the issue.
The supplier seems to think its a faulty low power device like a switch mode power supply.

Also there is another variable, the tennant who was experiencing the issues has now moved out and taken most of the electricals with him. This could be be good or bad I suppose. He may have taken the offending article with him and thus solved the problem?!

One thing we have considered is changing the phases between 2 of the apartments to see if anything changes?

[Edited on 10/11/20 by liam.mccaffrey]

If the tenet with the problem has moved I would sit tight, but maybe ask the others if they have any problems to inform the landlord/agent. it's likely to be something simple and the fault has "moved"...

https://www.bbc.co.uk/news/uk-wales-54239180