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Old 18th Jun 2017, 5:33 pm   #1
Mossdog
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Default Metamec clock - ring main?

About 10 years ago, while clearing my partner's parents' home, we took a lovely orange 1960s Metamec wall clock off their kitchen wall and stored it away as there wasn't a place for it in their new home. Recently re-discovering it, I'd like to mount it on the wall in our present kitchen.

Here's the problem. It was originally connected to a small square fused 2 amp plug, that I assume was wired into the old house's lighting circuit. That's not a readily available option at present so...I wonder if it's okay (read SAFE!) to replace completely the two core (no earth) cable with a modern, flat 2 core cable (N and Live) and run this to a new 5 amp plug (fitted with a 2 amp fuse), and plug this directly into a mains socket?

Many thanks for all advice.
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Old 18th Jun 2017, 5:51 pm   #2
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Default Re: Metamec clock - ring main?

There is no need to replace the original cable if it is in good condition.

It's impossible to make categorical statements at a distance, but there are no obvious dangers in doing what you intend to do. Most synchronous mains clocks used today are just plugged into normal 13A sockets, with a 3A or (better) 1A fuse in the plug. You can use a plug in RCD adaptor if you are especially worried about safety.

If you are unsure of your level of understanding of this subject, you should ask an electrician or other qualified person to check your work.
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Old 18th Jun 2017, 6:21 pm   #3
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Default Re: Metamec clock - ring main?

It should be fine, really.

As a rule, electric clocks tend to be fairly safe. The motor does not get especially hot in normal operation. It can overheat if stalled, but the windings are made of very thin wire and tend to fail open-circuit under fault conditions. And clocks generally are mounted fairly high up on a wall, for visibility; this also means they are unlikely to be touched accidentally. If your installation is protected by an RCD then even if somehow exposed metalwork on the clock becomes live and you manage to come into contact with it anyway, the RCD will protect you.

If you are very worried about the risk of fire, then you can fit a thermal fuse in contact with the motor stator windings.
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Old 18th Jun 2017, 7:21 pm   #4
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Default Re: Metamec clock - ring main?

Many thanks for your speedy replies - that's really very helpful
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Old 18th Jun 2017, 8:30 pm   #5
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Default Re: Metamec clock - ring main?

My only slight concern is the reference to a 5 amp plug fitted with a 2 amp fuse.
5 amp plugs are not normally fitted with fuses. Standard 5 amp round pin plugs that require fuses ARE available but are very rare.

Sockets that accept 5 amp round pin plugs should NOT be connected to ring mains.

If you have a 5 amp round pin socket, correctly installed, then yes a clock may be safely connected via a special fused plug preferably fitted with a 1 amp fuse.

If you have a standard ring main fitted with 13 amp sockets, then a clock may be connected thus, with a small fuse, preferably 1 amp in the plug.

If you have a standard type of 5 amp socket correctly installed, but a standard UNFUSED 5 amp plug , then in my view this should NOT be used to supply a clock, unless you can obtain one of the special 5 amp FUSED plugs .
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Old 18th Jun 2017, 8:38 pm   #6
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Default Re: Metamec clock - ring main?

You could use a BS73/BS372 two pin 5A plug (or the related BS4573 shaver plug, or a continental Europlug) in a shaver adaptor, which would provide the fusing. In most circumstances a standard BS1363 13A fused plug with an appropriate fuse would be a better idea though.
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Old 18th Jun 2017, 8:52 pm   #7
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Default Re: Metamec clock - ring main?

Quote:
Originally Posted by broadgage View Post
My only slight concern is the reference to a 5 amp plug fitted with a 2 amp fuse.
5 amp plugs are not normally fitted with fuses. Standard 5 amp round pin plugs that require fuses ARE available but are very rare.

Sockets that accept 5 amp round pin plugs should NOT be connected to ring mains.

If you have a 5 amp round pin socket, correctly installed, then yes a clock may be safely connected via a special fused plug preferably fitted with a 1 amp fuse.

If you have a standard ring main fitted with 13 amp sockets, then a clock may be connected thus, with a small fuse, preferably 1 amp in the plug.

If you have a standard type of 5 amp socket correctly installed, but a standard UNFUSED 5 amp plug , then in my view this should NOT be used to supply a clock, unless you can obtain one of the special 5 amp FUSED plugs .

Ah, I see. The plug is simply an 'off-the-shelf' standard 3 pin (not round) plug bought by myself from B & Q yesterday. It produced by Diall and is labelled "5 amp plug" and it has a 5A fuse already installed. My plan was to replace the 5A fuse with a 2A one, as that was the rating of the original fuse attached to the clock, and then wire it up to the 2 core cable (N and L terminals). Will still be sound?
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Old 18th Jun 2017, 9:07 pm   #8
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Default Re: Metamec clock - ring main?

That seems to be a 13A plug with a 5A fuse. Diall is a B&Q 'own brand'. If you are below a certain age you have probably never seen a 5A plug, but many of us on here grew up with them.
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Old 18th Jun 2017, 9:12 pm   #9
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Default Re: Metamec clock - ring main?

If you are getting confused about plug and socket types, this Wikipedia article has all you need to know (and more).
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Old 18th Jun 2017, 9:58 pm   #10
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Default Re: Metamec clock - ring main?

The shaver plug idea has already been suggested but if you are worried about the relative safety and the power consumption is low enough (which I would guess it would be) would a fused/transformer isolated shaver socket and appropriate plug do the trick? It would provide the extra fusing at a suitably low amperage plus have the extra safety of it being isolated.

Might be a stupid idea but just putting it out there.
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Old 18th Jun 2017, 10:14 pm   #11
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Default Re: Metamec clock - ring main?

Not a stupid idea at all dglcomp and thank you too, with all of the other replies, for taking the trouble of sharing your thoughts. I'm very grateful. So that's tomorrow night's project set
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Old 18th Jun 2017, 11:04 pm   #12
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Default Re: Metamec clock - ring main?

I don't know if I'm missing something here, but is there any reason why you can't simply use the correct flush-mounted clock socket with integral plug and 2Amp fuse, as was the norm prior to battery powered quartz clocks taking over from mains powered? Not especially cheap, but a search may bring up an alternative supplier at a lower price:

https://www.tlc-direct.co.uk/Product...WNIaAo-n8P8HAQ

Hope that helps.
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Old 18th Jun 2017, 11:33 pm   #13
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Default Re: Metamec clock - ring main?

Quote:
Originally Posted by broadgage View Post
If you have a standard type of 5 amp socket correctly installed, but a standard UNFUSED 5 amp plug , then in my view this should NOT be used to supply a clock, unless you can obtain one of the special 5 amp FUSED plugs.
Why? These clocks were sold all over the world and most places don't have fused plugs and yet there were no problems.
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Old 18th Jun 2017, 11:43 pm   #14
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Default Re: Metamec clock - ring main?

Quote:
Originally Posted by David G4EBT View Post
I don't know if I'm missing something here, but is there any reason why you can't simply use the correct flush-mounted clock socket with integral plug and 2Amp fuse
A clock socket is the ideal solution, but this would involve cutting channels in the plasterwork and redecorating - OK if you're having your kitchen refitted, but overkill otherwise.
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Old 19th Jun 2017, 12:05 am   #15
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Default Re: Metamec clock - ring main?

Quote:
Originally Posted by winston_1 View Post
Why? These clocks were sold all over the world and most places don't have fused plugs and yet there were no problems.
The more developed countries may have used unfused plugs for general domestic appliances, but DID tend to use UK type clock connectors with 1 amp fuses for electric clocks, at least in better specified premises.
Less developed places found little use for electric clocks since the mains frequency tended to vary too much.

And of course safety standards have changed, just because someone used an electric clock on a 15 amp circuit years ago, does not mean that this is to be encouraged today.
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Old 19th Jun 2017, 8:18 am   #16
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Default Re: Metamec clock - ring main?

Quote:
Originally Posted by paulsherwin View Post
A clock socket is the ideal solution, but this would involve cutting channels in the plasterwork and redecorating - OK if you're having your kitchen refitted, but overkill otherwise.
As I said Paul, I'm not sure what the intention is. If the intention is to run a surface mount cable to the clock position, provided there's space behind the clock, the clock socket could be mounted in a surface mount patress such as this one:

http://www.electricals247.co.uk/1-ga...hGEaAtkq8P8HAQ

However, on re-reading the original post, I'm getting the impression that whereas the term '2-core cable' was stated, (I think all mains voltage 'cable' is T&E - not twin), what was actually meant is 2-core flex, as used for small appliances such as table lamps, plugged into the nearest 13A ring main socket and run on the surface of the wall to the clock position. If so, I can't think of any reason why a 13A plug top can't be used, with a 1A or 2A fuse. That said, ordinarily, such flex isn't meant to be used in long surface-mount runs - generally up to 2 Metres from the appliance to the mains socket.

Still not really sure what the desired intention is.
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Old 19th Jun 2017, 8:42 am   #17
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Default Re: Metamec clock - ring main?

Make sure the flex is properly clamped at the clock end so it can't be pulled out exposing bare live wires.
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Old 8th Jul 2017, 7:43 pm   #18
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Default Re: Metamec clock - ring main?

Quote:
Originally Posted by Mossdog View Post
Ah, I see. The plug is simply an 'off-the-shelf' standard 3 pin (not round) plug bought by myself from B & Q yesterday. It produced by Diall and is labelled "5 amp plug" and it has a 5A fuse already installed. My plan was to replace the 5A fuse with a 2A one, as that was the rating of the original fuse attached to the clock, and then wire it up to the 2 core cable (N and L terminals). Will still be sound?
Yes.
Only you will have difficulty sourcing a 2A BS1362 fuse, and you'll probably end up using a 3A one.
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Old 8th Jul 2017, 8:40 pm   #19
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Default Re: Metamec clock - ring main?

Don't be obsessed with replicating historical what-it-would-have-been-connected-to-in-days-well-before-modern-electrical-standards. They were significantly less-safe than what you can easily achieve today.

Just use the 13A 3-pin plug you've already bought but fitted with a standard 3-amp fuse. And plug it into a normal 13A outlet.

if you're paranoid, use a RCD-adaptor - something like https://www.defenderpower.com/defend...r-240v-e11060c - between the 13A plug on your clock and the wall outlet.
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Old 8th Jul 2017, 9:27 pm   #20
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Default Re: Metamec clock - ring main?

Agreed.

If you really want to be careful, buy a 1A fuse (they are available though not from your local Tesco) and use an RCD adaptor. It's not really necessary though.
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