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Old 18th Mar 2023, 11:29 pm   #1
stickfly
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Default Metamec electric clocks. Unsafe?

Good evening,
I own a few Metamec electric clocks that I think are great clocks & run very well. I have replaced the old mains cable with modern cable over the years, as the originals were very old.
A few days ago I was talking to someone in a pub who said that Metamec electric clocks should not be plugged into the mains supply as they are dangerous by todays standards.
I did a search on the net & found an Australian site that agrees, saying that these clocks are a fire risk & a shock risk because they have no earth system + if the wires short to the mech' then the buttons become live.
Should I replace the 2 core cable with 3 core & attach the earth to the mech' to be safe, or is this rubbish.
Regards ..... Gary
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Old 19th Mar 2023, 10:40 am   #2
G.Castle
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Default Re: Metamec electric clocks. Unsafe?

I have one. (A local product i believe), they're not perhaps up to todays safety standards, but if run through a rcd protected supply and you use a one amp fuse in the plug/spur then they are no worse than any other vintage gear. I can't see how they could be a major fire risk. An insulation test may be an idea if you want to put your mind at rest.

It's in the Australian culture that consumer items should be powered from double wound transformers and have the crap earthed out of them, but then I don't know if they had a bigger prcentage of house fires caused by burning transformers than perhaps Europe or the USA?

I have three core mains flex on mine as it seemed the sensible thing to do.

Regards,
Greg
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Old 19th Mar 2023, 11:01 am   #3
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Default Re: Metamec electric clocks. Unsafe?

Opinions do differ a lot on the safety of old synchronous clocks. The predominant view is that they are acceptably safe if used sensibly, but there is a minority view that they are inherently unsafe and should only be used if rewound for low voltage operation.

Remember that touching a live electric clock will very rarely be fatal anyway as your body won't be earthed. (You'll certainly know about it though )

It's true that Australia has a strong electrical safety culture. Strict regulations were used as a way to discourage electrical imports in the 50s and 60s, a form of economic protectionism.
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Old 19th Mar 2023, 11:26 am   #4
Lucien Nunes
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Default Re: Metamec electric clocks. Unsafe?

Class 0 equipment (neither earthed nor double-insulated) has minimal protection against electric shocks designed-in. But the actual risk level depends on the quality of the insulation and whether it has deteriorated over time. Much of the risk is mitigated by the use of RCDs which were not available when this equipment was being made.

My preference is not to modify but to ensure I test RCDs regularly and when dealing with something unusually dangerous (e.g. devices from 100 years ago with exposed live parts) to use an isolating transformer.
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Old 19th Mar 2023, 11:57 am   #5
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Default Re: Metamec electric clocks. Unsafe?

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Originally Posted by G.Castle View Post
I have one. (A local product i believe)
Metamec's manufacturing was indeed in East Dereham, and as the operation only began in 1947 I would expect their products to be less of a hazard than at least some clocks produced a decade or so earlier: beyond that it's hard to generalise as they made a wide variety of items. The only one I remember us having was an alarm clock from c.1970 that sat on my father's bedside table: finding similar Metamec clocks online has confirmed my memory that it had no exposed metal parts beyond a couple of screw heads at the back, so in that instance at least shock hazard in normal use should be minimal to zero.

Paul
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Old 19th Mar 2023, 12:30 pm   #6
Mike Phelan
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Default Re: Metamec electric clocks. Unsafe?

I might put an earth lead on, but in my opinion if the motor is rewound with mains supply and a new supply cable there is hardly any risk.
  • Don't listen to pub culture.
  • Over the years, I wonder how many folk have been killed by electric clocks? Any?
  • Rewinding with low voltage is vandalism, IMHO.
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Old 19th Mar 2023, 12:38 pm   #7
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Default Re: Metamec electric clocks. Unsafe?

I’m quite a risk-averse person with a young family, but I have a dozen mains clocks round the house doing their thing all day every day.
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Old 19th Mar 2023, 12:53 pm   #8
G.Castle
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Default Re: Metamec electric clocks. Unsafe?

IMHO rewinding for low voltage is just moving the potential fire hazard! If rewinding is considered necessary then do it for line voltage, using nomex former material, modern hi temp., ECW, and resin impregnation, plus an imbedded thermal fuse would be the lowest risk. Mine runs barely warm, so it stays as it is.
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Old 19th Mar 2023, 1:40 pm   #9
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Default Re: Metamec electric clocks. Unsafe?

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Originally Posted by Mike Phelan View Post
I might put an earth lead on, but in my opinion if the motor is rewound with mains supply and a new supply cable there is hardly any risk.
Mike, I’m not sure if I’m misunderstanding what you sad, but are you really suggesting rewinding the coil on an already-working movement?
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Old 19th Mar 2023, 3:55 pm   #10
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Default Re: Metamec electric clocks. Unsafe?

Never had a problem with any of my Metamec clocks.

I was greatly amused by the concept of electrical safety in Australia as Australian mains plugs are probably the very worst I have encountered in my travels with their thin little blades.
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Old 19th Mar 2023, 5:14 pm   #11
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Default Re: Metamec electric clocks. Unsafe?

I have a modest collection of electric clocks, mainly Smiths, with cases of bakelite, perspex or wood. None have metal cases and I don't think that any have an earth connection anywhere. Even if a clock were to suffer serious internal electrical leakage, I reckon I'd have to try really hard in order to feel even a tingle from it. For example, I could take it into the bathroom and find some exposed internal metalwork big enough to get hold of whilst at the same time holding on to the cold water tap with the other hand.

In any case, an electric clock is typically handled only twice a year at the time of the hour change. Better to devote our limited technical resources to solving other more prominent safety issues such as safely handling an AR88 without specialist lifting gear.

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Old 19th Mar 2023, 5:26 pm   #12
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Default Re: Metamec electric clocks. Unsafe?

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Originally Posted by Paul_RK View Post

Metamec's manufacturing was indeed in East Dereham.

Paul
I visited the factory shop there back in the '90s. Bought several clocks too. All battery quartz. Not sure if the clocks were assembled there, or it was now just a warehouse.
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Old 19th Mar 2023, 5:37 pm   #13
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Default Re: Metamec electric clocks. Unsafe?

Some of the early Metamec electric clocks had metal knobs and not much of a cord grip. In theory, if a wire came loose inside the clock, parts of it could become live. In practice this is only likely to happen if the clock is abused, for example by someone pulling the wire.

Later Metamec clocks have plastic knobs and cases with no exposed metal parts that could become live.

There is a theoretical risk of fire if the motor coil develops shorted turns and overheats. I don't know if this has ever happened, or if it has, how often. Certainly there's been no official recall notice. There were millions of these clocks in use in the past. I haven't heard of any actual incidents. The risk must be vanishingly small.

Safety standards have been tightened over the years, but nothing can be 100% safe. Adding an Earth wire, RCD or thermal fuse will reduce the irisk further. Even rewinding the coil and running it on low voltage does not eliminate all risk. The Made In China low-voltage transformer could go faulty; its thermal fuse could fail to operate then burn your house down. Or the plug top could come apart, exposing live parts. Sure, the risk is vanishingly small, but it's still there. Nonetheless, some dealers are promoting the idea of converting mains electric clocks to low violtage because it absolves them of liability. They can sell a clock that doesn't comply with modern mains electricity standards with a compliant plug-in transformer, then blame the transformer supplier if something goes wrong.

Just because a vintage clock doesn't comply with modern standards, doesn't mean it's highly dangerous. Some common sense is required, for example replace frayed wiring and don't let children tamper with it. Think about it another way. You're far more likely to be killed in a road accident than by an old electric clock. Does that mean we should ban all cars or never cross the road because it's dangerous? Of course not. We all have to accept a small element of risk in our lives. I don't think old electric clocks are particularly high-risk unless there's obvious damage like a broken case exposing live parts or bare wires.

For the record I currently have a 1970s Metamec Sunburst electric wall clock and a 1939 Smiths Rangoon electric clock with hourly strike, both running continuously with no problems. I have other vintage electric clocks which have been used for long periods in the past. My advice: Use them and enjoy them, don't worry too much about the tales of potential doom.
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Old 19th Mar 2023, 5:59 pm   #14
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Default Re: Metamec electric clocks. Unsafe?

Quote:
Originally Posted by hamid_1 View Post
The Made In China low-voltage transformer could go faulty; its thermal fuse could fail to operate then burn your house down. Or the plug top could come apart, exposing live parts.
I've had this happen to me professionally - where a Chinesium PSU didn't current limit on a short and proceeded to melt and consequently set fire to a cable connected to it and IIRC at least a couple of plug-top PSU cases coming apart when withdrawn from a socket - I seem to recall a recall notice being issued by CPC on a unit they sold many years ago.

Just enjoy the clocks and don't fret, I say. My mother had an early one in regular use (it's pictured in Clifford Bird's book) until her death in 2008 with no issues, well over forty years without oiling or anything. I never did get it to "tick" though.
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Old 19th Mar 2023, 6:02 pm   #15
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Default Re: Metamec electric clocks. Unsafe?

Quote:
Originally Posted by Hartley118 View Post
Better to devote our limited technical resources to solving other more prominent safety issues such as safely handling an AR88 without specialist lifting gear.
We used to have battery-powered lifts at work for handling widescreen CRT monitors. I wish I had one to lift my radiograms with!
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Old 19th Mar 2023, 11:50 pm   #16
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Default Re: Metamec electric clocks. Unsafe?

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Originally Posted by Cathovisor View Post
I was greatly amused by the concept of electrical safety in Australia as Australian mains plugs are probably the very worst I have encountered in my travels with their thin little blades.
No worse than the thin blades on “kettle plugs” which are used worldwide at 10 amps.
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Old 20th Mar 2023, 12:34 am   #17
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Default Re: Metamec electric clocks. Unsafe?

Just to further put things in perspective for the OP.
Go into you kitchen and look down into the slots of your fully compliant pop-up toaster.
Now tell me if it's less dangerous to handle than the clock!

Another good idea if a BS1363 plug is fitted, change the fuse to one like this:
Click image for larger version

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The clock plug obviously, not the toaster
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Old 20th Mar 2023, 2:57 pm   #18
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Default Re: Metamec electric clocks. Unsafe?

I converted a mains metamec into a battery quartz one a while back (in fact I've done a few now) but only for convenience's sake, as the mains around here is not reliable enough to operate a clock for long and in any case I didn't want cables running along the mantlepiece. Don't worry, the movements are stored safely.

The last one I did had figure-of-8 old-style pvc table lamp flex, but it went into the clock's coil which was on a plastic former, all covered by a plastic cap. I'd have though the coil leadouts would fuse (they're very fine!) if the coil started burning out.

Maybe the electric clock paranoia is thanks to a recent 'conversion' on the Repair Shop where the clock guy (or maybe voiceover man) said they were no longer considered safe. I can't remember if it was a metamec or smiths or something else.
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Old 20th Mar 2023, 3:20 pm   #19
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Default Re: Metamec electric clocks. Unsafe?

There have been people banging on about the supposed dangers of synchronous clocks for as long as I can remember.
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Old 20th Mar 2023, 4:12 pm   #20
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Default Re: Metamec electric clocks. Unsafe?

Quote:
Originally Posted by McMurdo View Post
Maybe the electric clock paranoia is thanks to a recent 'conversion' on the Repair Shop where the clock guy (or maybe voiceover man) said they were no longer considered safe. I can't remember if it was a metamec or smiths or something else.
That will be it! A remark made on the Repair Shop, then gossip in the pub, and before you know it, it's a true fact. In real life.

From my own point of view, there are certainly SOME safety concerns, mainly the perished VIR flexes found on some prewar models, the dinky little 2A power connectors with relatively large female receptacles recessed by barely 1/32", and the lack of earth connection - especially on some models where the wires to the coil pass through holes in the metalwork, where the insulation is often found cracked and deficient (Smiths Bijou movement). But with some common sense and a bit of TLC, none of this need be a problem in reality.

What is much more of a concern to me is the odd seller on auction sites etc. selling clocks which are apparently "fitted with a safe, new cable and PAT tested", implying that they comply with C21st safety standards and can be treated as such. The pictures often show the mains flex grafted onto the clock's terminals using insulated crimps which would be more at home in a car and provide less touch-protection than the original "dangerous" Bakelite connector, and a 13A fuse.
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