Any ideas on what this would used on - UK Vintage Radio Repair and Restoration Discussion Forum

Luxman1050 · 29th Nov 2019, 2:08 pm

Hi all
anybody got any ideas on what this 240vac current test plug would be used on and how it's supposed to work.
Stumped me! Like to try it out.

Cheers Chris

Peter.N. · 29th Nov 2019, 2:14 pm

Looks like one of those things that service departments would give apprentices to plug in.

Is there actually anything inside the sleeving or are the ends just connected together?

Peter

Herald1360 · 29th Nov 2019, 2:46 pm

Looks like a " Little Wonder" fuse tester to me.

Dyeing trousers, perhaps?

newlite4 · 29th Nov 2019, 3:20 pm

Perhaps it plugs into a test panel and a current clamp meter is fed through the loop.
Neil

Luxman1050 · 29th Nov 2019, 3:21 pm

No it's just connected in a loop and just says on bit paper stuck on wires to test ac current 240v. Not sure what the grey bit for as there is no wire exposed as I thought maybe you put a clip on it or something.

G6Tanuki · 29th Nov 2019, 4:24 pm

I've seen similar things used as a primitive safety-interlock: the matching socket would be wired in series with the live side of the supply to a piece of gear/installation/panel. The plug acts as a shorting-link; you remove it and take it with you when you need to do work on the panel. Using an obscure plug/socket in such applications reduces the chance of someone-else kludging together a bypass - the US 2-flat-pin plugs/sockets are rather handy for this sort of thing.

Luxman1050 · 29th Nov 2019, 4:39 pm

So is it used on valve gear and why would you need to create a short circuit? Or is it that you bypass the mains on piece of equipment so you can work on different parts components.
When you say panel do you mean the chassis?
Dumb questions which I think you answered.

Cheers Chris

G6Tanuki · 29th Nov 2019, 5:54 pm

It'd be wired in series with the [mains] power-supply to a piece of equipment; with the plug/link in-place, power is applied to the equipment. Remove the plug/link and the power is cut off, and you can take the link away with you to prevent anyone else restoring the power while you're working on the equipment (as could happen with a simple switch).

[If an isolating switch is used then it should have some mechanism for a padlock-and-tag to be fitted to prevent anyone unauthorised from re-applying power]

By "panel" I mean something like an industrial control-panel or the contactors/switchgear in something like a lift or heavy machinery.

Luxman1050 · 29th Nov 2019, 7:54 pm

Ah I see simple but effective.
Thanks for that.

Much appreciated Chris

Station X · 29th Nov 2019, 9:08 pm

Why would a shorting link require such a long length of wire attached to it?

Quote:

Originally Posted by G6Tanuki

I've seen similar things used as a primitive safety-interlock: the matching socket would be wired in series with the live side of the supply to a piece of gear/installation/panel. The plug acts as a shorting-link; you remove it and take it with you when you need to do work on the panel. Using an obscure plug/socket in such applications reduces the chance of someone-else kludging together a bypass - the US 2-flat-pin plugs/sockets are rather handy for this sort of thing.

sortedradio · 29th Nov 2019, 9:19 pm

I would tend to agree with Neil that it's for a clamp meter, especially as the label states "to test ac current 240v". The grey plastic is probably to prevent the wire being damaged accidentally by the clamp.

Station X · 29th Nov 2019, 9:26 pm

That makes sense.

G6Tanuki · 29th Nov 2019, 10:00 pm

Quote:

Originally Posted by Station X

Why would a shorting link require such a long length of wire attached to it?

To make it easier to hook to your belt before walking away. When I dealt with such things you always had to physically-attach the disabler to your person. A short loop could be inconvenient for this.

[The same sort-of approach is used in the 'kill-switch' lanyards on powerboarts/jetskis which kill the engine if you fall off]

Peter.N. · 30th Nov 2019, 11:37 am

Its got an exceedingly old 2 pin 5a plug on it so I would think its dated to the '50s if not the '40s.

Peter

Luxman1050 · 30th Nov 2019, 12:15 pm

Thanks for replies guys in effect it's just a safety feature as far as I can make out from replies it is connected in series with mains and if removed renders the equipment non usable if you tried to plug it in that's what I can make out. I'm not sure I'll get round to use it as it was obviously for an electrical engineer as mentioned from 40s 50s. Just interesting when you come across gear like this having no idea what it was used for.

Cheers Chris

stuarth · 30th Nov 2019, 1:56 pm

The long wire may be just to get the clamp meter in a more convenient place. There may have been a much shorter wire, or even a shorting plug to avoid having the long wire dangling about in normal operation.

Stuart

29th Nov 2019, 2:08 pm	#1
Luxman1050 Octode Join Date: Apr 2019 Location: Margate, Kent, UK. Posts: 1,728	Any ideas on what this would used on Hi all anybody got any ideas on what this 240vac current test plug would be used on and how it's supposed to work. Stumped me! Like to try it out. Cheers Chris Attached Thumbnails

29th Nov 2019, 2:14 pm	#2
Peter.N. Dekatron Join Date: Jul 2008 Location: Charmouth, Dorset, UK. Posts: 3,601	Re: Any ideas on what this would used on Looks like one of those things that service departments would give apprentices to plug in. Is there actually anything inside the sleeving or are the ends just connected together? Peter

29th Nov 2019, 2:46 pm	#3
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Any ideas on what this would used on Looks like a " Little Wonder" fuse tester to me. Dyeing trousers, perhaps? __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

29th Nov 2019, 3:20 pm	#4
newlite4 Octode Join Date: Nov 2003 Location: Bath, Somerset, UK. Posts: 1,805	Re: Any ideas on what this would used on Perhaps it plugs into a test panel and a current clamp meter is fed through the loop. Neil __________________ preserving the recent past, for the distant future.

29th Nov 2019, 3:21 pm	#5
Luxman1050 Octode Join Date: Apr 2019 Location: Margate, Kent, UK. Posts: 1,728	Re: Any ideas on what this would used on No it's just connected in a loop and just says on bit paper stuck on wires to test ac current 240v. Not sure what the grey bit for as there is no wire exposed as I thought maybe you put a clip on it or something.

29th Nov 2019, 4:24 pm	#6
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,998	Re: Any ideas on what this would used on I've seen similar things used as a primitive safety-interlock: the matching socket would be wired in series with the live side of the supply to a piece of gear/installation/panel. The plug acts as a shorting-link; you remove it and take it with you when you need to do work on the panel. Using an obscure plug/socket in such applications reduces the chance of someone-else kludging together a bypass - the US 2-flat-pin plugs/sockets are rather handy for this sort of thing.

29th Nov 2019, 4:39 pm	#7
Luxman1050 Octode Join Date: Apr 2019 Location: Margate, Kent, UK. Posts: 1,728	Re: Any ideas on what this would used on So is it used on valve gear and why would you need to create a short circuit? Or is it that you bypass the mains on piece of equipment so you can work on different parts components. When you say panel do you mean the chassis? Dumb questions which I think you answered. Cheers Chris

29th Nov 2019, 5:54 pm	#8
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,998	Re: Any ideas on what this would used on It'd be wired in series with the [mains] power-supply to a piece of equipment; with the plug/link in-place, power is applied to the equipment. Remove the plug/link and the power is cut off, and you can take the link away with you to prevent anyone else restoring the power while you're working on the equipment (as could happen with a simple switch). [If an isolating switch is used then it should have some mechanism for a padlock-and-tag to be fitted to prevent anyone unauthorised from re-applying power] By "panel" I mean something like an industrial control-panel or the contactors/switchgear in something like a lift or heavy machinery.

29th Nov 2019, 7:54 pm	#9
Luxman1050 Octode Join Date: Apr 2019 Location: Margate, Kent, UK. Posts: 1,728	Re: Any ideas on what this would used on Ah I see simple but effective. Thanks for that. Much appreciated Chris

29th Nov 2019, 9:19 pm	#11
sortedradio Heptode Join Date: Jan 2008 Location: Sheffield, South Yorkshire, UK. Posts: 656	Re: Any ideas on what this would used on I would tend to agree with Neil that it's for a clamp meter, especially as the label states "to test ac current 240v". The grey plastic is probably to prevent the wire being damaged accidentally by the clamp. __________________ Martin BVWS member GQRP Club

29th Nov 2019, 9:26 pm	#12
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: Any ideas on what this would used on That makes sense. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

30th Nov 2019, 11:37 am	#14
Peter.N. Dekatron Join Date: Jul 2008 Location: Charmouth, Dorset, UK. Posts: 3,601	Re: Any ideas on what this would used on Its got an exceedingly old 2 pin 5a plug on it so I would think its dated to the '50s if not the '40s. Peter

30th Nov 2019, 12:15 pm	#15
Luxman1050 Octode Join Date: Apr 2019 Location: Margate, Kent, UK. Posts: 1,728	Re: Any ideas on what this would used on Thanks for replies guys in effect it's just a safety feature as far as I can make out from replies it is connected in series with mains and if removed renders the equipment non usable if you tried to plug it in that's what I can make out. I'm not sure I'll get round to use it as it was obviously for an electrical engineer as mentioned from 40s 50s. Just interesting when you come across gear like this having no idea what it was used for. Cheers Chris

30th Nov 2019, 1:56 pm	#16
stuarth Heptode Join Date: Feb 2010 Location: Heysham, Lancashire, UK. Posts: 669	Re: Any ideas on what this would used on The long wire may be just to get the clamp meter in a more convenient place. There may have been a much shorter wire, or even a shorting plug to avoid having the long wire dangling about in normal operation. Stuart