Wiring up a Smiths Sectric Clock - UK Vintage Radio Repair and Restoration Discussion Forum

vespadouglas · 19th Dec 2014, 9:41 pm

I have a Smiths Sectric Clock. On the back there is a bakelite connector with room for two wires. Does anyone know if I should be safe with just two wires - live and neutral or if an earth is also required, if so where should the earth wire onto. Thanks in advance for any advice.

broadgage · 20th Dec 2014, 7:24 am

The original looking 2 pole connector strongly suggests that the clock was not intended to be earthed, also electric clocks were usually connected to lighting circuits which often had no earth conductor.

Some would consider that an earth connection should be added these days, but I would probably not bother.

Mike Phelan · 20th Dec 2014, 10:15 am

Originally as BG says, they had no earth as they were generally connected to a 2-pin wall mounted clock socket with its own fuse.

Generally, but not always, I earth synchronous electric clocks with a 3-core lead; if it was originally fabric covered I make up a lead like that.

With a clock like yours I tend not to bother as there's not much metalwork exposed; if you want to earth it then probably any screws or nuts that go into the movement would be the best way, using a very thin 3-core mains lead.

vespadouglas · 20th Dec 2014, 3:17 pm

Thanks for the information, it jogged my memory that a similar old Smiths clock at work was indeed wired into the light circuit. I will add an earth wire as I have two boys who are still yet to understand the danger of mains electricity. What fuse would you recommend in the plug? I will fit some flex to test that the clock works and then buy some fabric covered wire. Is there anything else I should be doing to the mechanism or is it best to leave well alone?
thanks

Tractorfan · 20th Dec 2014, 4:46 pm

Hi,
Clock connectors had a small 1amp fuse and, if you use a 13amp plug, a BS1362 1amp fuse should be fitted to that. However, they can be tricky to find (I think), so a 3amp one would have to do. Certainly nothing larger.
Personally, I wouldn't earth a clock like that as the current carrying parts are inside the bakelite housing which is inside a bakelite case behind a glass cover. The only exposed metal will be the dial, and if the clock is on the wall out of reach, I don't see a problem. But that's just me.
Cheers, Pete.

Mike Phelan · 20th Dec 2014, 6:11 pm

The dial won't be exposed as the OP's pics show that the glass is present.

If it works, just leave it. It is true that clocks ought to be serviced at least every ten years but unless you're familiar with dismantling and lubrication, best just leave it.

Many problems are caused by folk putting oil or worse WD40 all over the mechanism!

Tractorfan · 20th Dec 2014, 6:33 pm

Hi,
That's what I meant, Mike. Just got my words muxed ip!
Cheers, Pete.

vespadouglas · 20th Dec 2014, 11:30 pm

Thanks for updated information. I'm sat ready with screwdriver and lead. There is no indication on two pole connector of live, neutral etc. I assume it doesn't make any difference which way the wires go?

Mike Phelan · 21st Dec 2014, 10:07 am

Correct, it doesn't. The leads simply go to a coil on the motor stator.

vespadouglas · 21st Dec 2014, 11:15 pm

I managed to find a 1amp fuse. The clock movement sounded very scratchy when first powered up. It seems to have settled down and is now ticking away smoothly and keeping time.
Thanks for all of the very helpful information.

19th Dec 2014, 9:41 pm	#1
vespadouglas Retired Dormant Member Join Date: Dec 2014 Location: Alcester, Warwickshire, UK. Posts: 4	Wiring up a Smiths Sectric Clock I have a Smiths Sectric Clock. On the back there is a bakelite connector with room for two wires. Does anyone know if I should be safe with just two wires - live and neutral or if an earth is also required, if so where should the earth wire onto. Thanks in advance for any advice. Attached Thumbnails

20th Dec 2014, 7:24 am	#2
broadgage Nonode Join Date: Jan 2010 Location: North Somerset, UK. Posts: 2,130	Re: Wiring up a Smiths Sectric Clock The original looking 2 pole connector strongly suggests that the clock was not intended to be earthed, also electric clocks were usually connected to lighting circuits which often had no earth conductor. Some would consider that an earth connection should be added these days, but I would probably not bother.

20th Dec 2014, 10:15 am	#3
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Re: Wiring up a Smiths Sectric Clock Originally as BG says, they had no earth as they were generally connected to a 2-pin wall mounted clock socket with its own fuse. Generally, but not always, I earth synchronous electric clocks with a 3-core lead; if it was originally fabric covered I make up a lead like that. With a clock like yours I tend not to bother as there's not much metalwork exposed; if you want to earth it then probably any screws or nuts that go into the movement would be the best way, using a very thin 3-core mains lead. __________________ Mike. Last edited by Mike Phelan; 20th Dec 2014 at 6:04 pm. Reason: Typo.

20th Dec 2014, 3:17 pm	#4
vespadouglas Retired Dormant Member Join Date: Dec 2014 Location: Alcester, Warwickshire, UK. Posts: 4	Re: Wiring up a Smiths Sectric Clock Thanks for the information, it jogged my memory that a similar old Smiths clock at work was indeed wired into the light circuit. I will add an earth wire as I have two boys who are still yet to understand the danger of mains electricity. What fuse would you recommend in the plug? I will fit some flex to test that the clock works and then buy some fabric covered wire. Is there anything else I should be doing to the mechanism or is it best to leave well alone? thanks

20th Dec 2014, 4:46 pm	#5
Tractorfan Dekatron Join Date: Mar 2008 Location: St. Frajou, l'Isle en Dodon, Haute Garonne, France.(Previously: Ellesmere Port, Cheshire, UK.) Posts: 3,184	Re: Wiring up a Smiths Sectric Clock Hi, Clock connectors had a small 1amp fuse and, if you use a 13amp plug, a BS1362 1amp fuse should be fitted to that. However, they can be tricky to find (I think), so a 3amp one would have to do. Certainly nothing larger. Personally, I wouldn't earth a clock like that as the current carrying parts are inside the bakelite housing which is inside a bakelite case behind a glass cover. The only exposed metal will be the dial, and if the clock is on the wall out of reach, I don't see a problem. But that's just me. Cheers, Pete. __________________ "Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..."

20th Dec 2014, 6:11 pm	#6
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Re: Wiring up a Smiths Sectric Clock The dial won't be exposed as the OP's pics show that the glass is present. If it works, just leave it. It is true that clocks ought to be serviced at least every ten years but unless you're familiar with dismantling and lubrication, best just leave it. Many problems are caused by folk putting oil or worse WD40 all over the mechanism! __________________ Mike.

20th Dec 2014, 6:33 pm	#7
Tractorfan Dekatron Join Date: Mar 2008 Location: St. Frajou, l'Isle en Dodon, Haute Garonne, France.(Previously: Ellesmere Port, Cheshire, UK.) Posts: 3,184	Re: Wiring up a Smiths Sectric Clock Hi, That's what I meant, Mike. Just got my words muxed ip! Cheers, Pete. __________________ "Hello?, Yes, I'm on the train, I might lose the signal soon as we're just going into a tunn..."

20th Dec 2014, 11:30 pm	#8
vespadouglas Retired Dormant Member Join Date: Dec 2014 Location: Alcester, Warwickshire, UK. Posts: 4	Re: Wiring up a Smiths Sectric Clock Thanks for updated information. I'm sat ready with screwdriver and lead. There is no indication on two pole connector of live, neutral etc. I assume it doesn't make any difference which way the wires go?

21st Dec 2014, 10:07 am	#9
Mike Phelan Dekatron Join Date: Nov 2003 Location: Near Leeds, West Yorkshire, UK Posts: 4,609	Re: Wiring up a Smiths Sectric Clock Correct, it doesn't. The leads simply go to a coil on the motor stator. __________________ Mike.

21st Dec 2014, 11:15 pm	#10
vespadouglas Retired Dormant Member Join Date: Dec 2014 Location: Alcester, Warwickshire, UK. Posts: 4	Re: Wiring up a Smiths Sectric Clock I managed to find a 1amp fuse. The clock movement sounded very scratchy when first powered up. It seems to have settled down and is now ticking away smoothly and keeping time. Thanks for all of the very helpful information.