Premature failure of appliances

[littlespark]

A parent at the school asked me why they might be going through a lot of appliances.
Washing machine less than 4 years.
kettle 3 years and LED lamps, less than 6 months.
There were other things, but can’t remember lifespan.

I popped in on passing one day and did a quick test on the kettle socket. (Didn’t go to the length of taking the db apart this time)

voltage was 248v, Zs at the socket was 0.91
TNC-S, not an overhead line, buried. But the houses are down a little valley, so I’m guessing they’re on the end of the supply cable.
They don’t know if any of the other houses have had the same issues.

20 year old installation, in a much older renovated cottage.
First thought was overvoltage, but 248 is high, but ok.
They haven’t noticed if any light brightness fluctuates, indicating fluctuating voltage, but I don’t think there is any tungsten lamps, all LED or cfl.

Anything else to look for if I go back for a proper visit?

 

[Midwest]

Probably just rubbish appliances. Reading in the news this week that manufactures will be forced to make their appliances more robust. To stop the throw away concept. Forced to make spares more available and construct them so they can be more easily repaired. Screws together not glued, like in some phones.

 

[pc1966]

Could just be crap appliances of course!

A kettle is not something I can see being damaged by over-voltage transients (unless it has some pointless electronic controller). Modern washing machines and LED lights could be, but unless there is some nearby factory with big inductive loads causing regular spikes on the supply I would expect them to have noticed, say, lightning storm and stuff then not working.

A really flaky switch on some feed causing a lot of arcing and hence a lot of high frequency current in to electronic filters, power supplies, etc, migh also be a reason, again but I would also imagine the crackles would be noticed.

 

[R-fur]

Remember appliances are designed for 230V so 248V is 8% over.

 

[Wilko]

Hi - my Sunday 20p worth - a manufacturer’s design, materials and construction is aimed at an appliance providing good service for the warranty period “plus a bit“. The “plus a bit“ will hopefully allow for more frequent use, tougher environments and varied supply quality conditions (say). If the appliances last beyond their warranty period (as it seems) and there are no mass extinction events (as it seems) then what you’ve described doesn’t seem to indicate a supply fault. Sorry, but appliances are built to a price.

 

[Vortigern]

I don't know if there is any relation to being at the end of the line as you put it. I have noticed especially in previous years when incandescent filament lamps were all the rage that the last light on the circuit always blew much more often than the other bulbs on the circuit. I was often asked why this happens and could never explain it.

 

[marconi]

Maybe a deteriorating CNE connection/conductor between supply transformer star point and client's home - your client's home is at the end of a daisy chain of them meaning that their L-N voltage may be determined/influenced by external loads connected between phases and N.

Be interesting to know PSSC at DB incomer to calculate Z of external L-N cable loop back to transformer. Perhaps compare it to some other homes' PSSC/Z up along the valley.

 

[littlespark]

There is a farm at the top of the hill down into the valley, and there’s 2 other houses past the one I visited out of maybe a dozen??
All depends on how the other houses are arranged... supply being buried, I can’t tell. But they could be the last off L1, and the 2 past it are off L2 and L3.... just don’t know.

crappy appliances are likely, but they’re not the type of family to buy cheap tat.... maybe expensive tat. Bought brand name over quality.
oven is a hotpoint, but element going on that may just be coincidence.
I’ll get the PSC And Ze at the board if I go back.
They’ve got the house up for sale anyway, so they might just move and forget about it.

The appliances should be designed for the range that the supplier can give, which is 230 -6% or +10%
so anything between 216.2v and 253v, but obviously closer to 230 the better.
Supplier won’t look at it as an overvoltage at 248v but maybe there’s surges?

 

[FatAlan]

Probably just rubbish appliances. Reading in the news this week that manufactures will be forced to make their appliances more robust. To stop the throw away concept. Forced to make spares more available and construct them so they can be more easily repaired. Screws together not glued, like in some phones.

Isn’t that just a sensible EU law that we in the UK will now be able to ignore to our detriment and the will of the current set of corrupt leaders!

 

[telectrix]

you get what you pay for. our double oven was installed in 1997. so far it's had 1 new element ( 2 years ago ). recently the clock display has falied due to burnt tracks etc. on PCB. however, it still cooks, so untill i can source a replacement PCB, 'er indoors will have to guess . lot of peeps would scrap and buy new. sod that.... new oven costs 3 months beer money.

 

[Midwest]

Isn’t that just a sensible EU law that we in the UK will now be able to ignore to our detriment and the will of the current set of corrupt leaders!

Piece I read, said UK will probably follow. Makes sense to me. Nothing seems worthwhile repairing now. Got a draw full of phones now.

 

[telectrix]

Piece I read, said UK will probably follow. Makes sense to me. Nothing seems worthwhile repairing now. Got a draw full of phones now.

an old smart phone with a pay as you go sim card (so it all works) makes an excellent dash cam.

 

[Midwest]

an old smart phone with a pay as you go sim card (so it all works) makes an excellent dash cam.

Yep, but trouble is, all my old ones are buggered.

 

[telectrix]

Yep, but trouble is, all my old ones are buggered.

i have a working sony for sale cheap.

 

[Midwest]

i have a working sony for sale cheap.

Your alright tks

 

[radiohead]

Isn’t that just a sensible EU law that we in the UK will now be able to ignore to our detriment and the will of the current set of corrupt leaders!

Spot the liberal leftie handwringer!

 

[pc1966]

Remember appliances are designed for 230V so 248V is 8% over.

The EU and UK voltage spec since 1995 is 230V +10% -6%

So anything between 216V and 253V is correct and should not present a problem with a competent design. Therein lies the rub...
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I don't know if there is any relation to being at the end of the line as you put it. I have noticed especially in previous years when incandescent filament lamps were all the rage that the last light on the circuit always blew much more often than the other bulbs on the circuit. I was often asked why this happens and could never explain it.

After my earlier post I did think of two other bits of info to throw in to this discussion.

One was exactly your point about long cables and if you are switching loads on a long transmission line you can get spikes (electrical equivalent of the "water hammer" in plumbing). In the past I would have ignored this for AC power systems as it usually a high speed electronics problem, but then if you have several km of wire then it will be apparent at much lower frequencies. Also it would not normally give spikes of more than the supply voltage on top, so you should not see peaks beyond about 700V and that should be within design limits for non-crap electronics. If it is the reason, then fitting a SPD might help, but it would be hard to establish that given it takes months or years for failures to show up.

The other thing that was mentioned was the above-average voltage. Now that should not be a problem, but I have seen so called "Voltage Optimisation" devices sold and, as best I can tell, they are really something like an auto-transformer to reduce the supply to closer to the nominal 230V. They are pushed as a power-saving device but I smell snake oil there... But if they are buying brands that are good elsewhere in the UK on the same nominal voltage that is not a likely explanation.