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General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc. |
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13th Feb 2015, 9:52 pm | #1 |
Dekatron
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It's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
In times past I regularly used the little circular Bulgin 3- and 6-pin plugs/sockets for 240VAC supplies.
They were conveniently small for low-current [up to a couple of Amps] connections; though the last few I bought have come with a warning that they're only suitable for 50V use "Unless inaccessible". Looking at them and comparing them to an IEC309 PC-type 'kettle-lead' plug/socket - which is rated for 240V - I consider the Bulgin variety to present rather less of a hazard than the IEC309 - in particular, the holes on the Bulgin free-socket are much smaller than those on the IEC309 free-socket and so provide significantly less of a hazard to wandering children-with-knitting-needles etc. The only possible compromise is that the Bulgin does not have a mechanical cord-grip. Personally, I'm happy to continue sinning and using the Bulgin-type where convenient and appropriate - but should I sell anything so-equipped I'd stick a disclaimer-label on the rear to indicate that it retained the use of a "non-currently-approved" connector. Last edited by G6Tanuki; 13th Feb 2015 at 9:59 pm. |
13th Feb 2015, 10:10 pm | #2 |
Nonode
Join Date: Jan 2010
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Re: it's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
As far as I am aware, the reason the Bulgin is now rated at 50V is that the cover can be unscrewed accidently without the use of tools. Had there been a locking screw that had to be removed before unscrewing the cap the rating would still be 240V.
Al
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13th Feb 2015, 10:20 pm | #3 |
Dekatron
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Location: Wiltshire, UK.
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Re: it's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
I can sort-of see the logic there [memories of the horrid 'Clix' 2-pin 5-amp plugs with the split-pins as contacts and easily-screw-on-and-offable cover as the only retainer come to mind]
I wonder if a good dose of superglue applied before screwing-on the cover would satisfy? |
13th Feb 2015, 10:33 pm | #4 |
Heptode
Join Date: Jan 2004
Location: Stockport, Greater Manchester, UK.
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Re: it's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
The PX0430/SE and PX0646 are the 3-pin ones suitable for mains.
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13th Feb 2015, 10:36 pm | #5 |
Dekatron
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Re: it's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
I guess because they've got positive cord-grips and the cover can't be unscrewed without use of a tool?
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13th Feb 2015, 10:43 pm | #6 |
Nonode
Join Date: Jan 2010
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Re: it's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
One of my areas of interest is guitar and PA amplifiers. From time to time I come across equipment that uses the larger version of that plug. Strictly speaking, a piece of equipment like that does not comply with current safety regulations so cannot be used in a public place. However, because it is 'vintage equipment' the plugs are still OK for 240V.
If the plugs are for vintage gear or for your own use they are probably still OK for mains. Gluing the covers on would turn the mains lead into one with a permanently attached plug so, I think, that would be OK too. Al
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13th Feb 2015, 10:47 pm | #7 |
Heptode
Join Date: Jan 2004
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Re: it's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
And the PX0430/SE should be available for a while yet as Farnell show stock of 15,216!
Last edited by G8UWM-MildMartin; 13th Feb 2015 at 10:49 pm. Reason: Clarify type |
19th Feb 2015, 10:20 am | #8 |
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Re: it's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
Plugs and sockets are not rated for shock hazard, or perception of this, but for voltage and current and insulation material.
The material must be fire resistant, (IEE regs). Accessories had to be safe in the fifties and they generally were, however time has enabled people to find ways of misuse,with various shock hazards from people poking fingers into holes etc. Hence shuttered sockets, these were also good for cutting out the arc when plug is withdrawn ,later fitted to AC only switchgear, ie BS1363 plug. In my opinion IEC320 series are not the best, the tiny flat pins don't make good contact,and the plug can be rocked in socket, ie not retained, They certainly would not be suitable for DC use. The Clix plug was in fact a good plug, the split spring pins made good contact, it was so quick and easy to fit, the cover once screwed on may not be easy to remove afterwards. However it was considered more for temporary use and was not a first choice. Last edited by happytiger; 19th Feb 2015 at 10:25 am. |
21st Feb 2015, 12:31 pm | #9 |
Heptode
Join Date: Jul 2010
Location: Wellington, New Zealand.
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Re: It's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
Amazing how safety conscious we've all become with the venerable bulgin 3 pins not good enough any more for mains - can recall when all the mains projects in 1960's Practical Electronics used to use them. Mind you at my infant school a decade or so earlier we listened to a valve radio that the headmaster connected by shoving a pencil in the wall mains socket earth pin (to raise the gate), then he pushed the live and neutral wires of the radio (with bare ends) into their respective sockets and pulled the pencil out until the gate came down and clamped the wires in place. God knows how he never fried himself or created a fire by arcing - LOL.
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21st Feb 2015, 5:59 pm | #10 |
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Re: It's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
The Bulgin mains connector is perfectly safe, it's the idiot who unscrews the cover of one that's in use that is in danger.
I know Douglas Adams beat me to this joke ("What's that?" "It's the ravenous bugblatter beast of Traal." "Is it safe?" "Oh yes, IT'S perfectly safe." ) I remember the old lightswitches with the screw-on covers. Anyone could remove the cover, and the next person groping around in the dark to find the switch stuck his hand across 220v. David
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21st Feb 2015, 7:12 pm | #11 |
Nonode
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Re: It's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
To me the answer's simple. If you're a hobbyist you can do what ever you like. If you're a professional then you have to follow manufacturers recommendations .
David
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21st Feb 2015, 7:40 pm | #12 |
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Re: It's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
As a hobbyist, you have some freedoms, but if someone else gets hurt by anything that can be laid at your door, you can wind up in court.
It gets worse if you have any qualifications in an associated field, because they then become evidence that you knew you were taking risks. If something bad happens, you can't pop back in a time-machine, the only time to take reasonable precautions is beforehand. We live in an increasingly litigious age and the only way to handle it is to ask yourself how you would defend your actions before you do anything which poses a hazard. Not long ago someone posted a tale on this group of how a judge threatened legal action against a TV repairman who had taken a set away but left the empty mains socket switched on, thus imperiling the judge from leaked electricity. These are the sorts of people we now have to defend ourselves from. David
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21st Feb 2015, 8:28 pm | #13 | |
Rest in Peace
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Re: It's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
Quote:
"Look at all those electrons flowing over my expensive Axminster carpet - and ruining it!" Al. |
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1st Mar 2015, 2:45 pm | #14 |
Heptode
Join Date: Jul 2010
Location: Wellington, New Zealand.
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Re: It's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
I've just discovered a new use for Bulgin 3 pin connectors - over here in NZ we get a lot of used US test gear that is 117 volts ac. NZ mains is 235 v ac. The market rules are this stuff MUST be sold with the US/foreign plug cut off (only NZ mains plugs allowed on used gear). I have a hefty mains transformer that provides the 117 v ac and I had already installed a Bulgin 3 pin socket on that transformer for another function, so it makes sense to equip the 117 volt ac gear with Bulgin plugs - also prevents the plugging stuff into 235 v ac by accident.
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6th Mar 2015, 8:31 am | #15 |
Dekatron
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Re: It's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
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6th Mar 2015, 12:07 pm | #16 |
Dekatron
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Re: It's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
Funnily enough, when European mains voltages were harmonized at a nominal 230V a few years ago, our own mains here in Brentwood dropped from 240V to 235V, and the mains at my brother-in-law's in France rose from 220V to 235V.
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6th Mar 2015, 1:25 pm | #17 | |
Dekatron
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Re: It's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
Quote:
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If I have seen further than others, it is because I was standing on a pile of failed experiments. Last edited by julie_m; 6th Mar 2015 at 1:27 pm. Reason: Added context |
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6th Mar 2015, 2:55 pm | #18 |
Nonode
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Re: It's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
Sadly the side entry versions of the larger 2 pin (P74) and 3 pin (P73) Bulgin cable
socket are not always convenient to use. I have devised a simple technique to make the old round ones a bit safer; 1. Enlarge the hole in the screw on top carefully (use a countersink or conecut bit) to accept a cable gland for the size of cable required e.g. http://uk.farnell.com/te-connectivit...ack/dp/1174601 2. With the lid screwed on, drill a 1mm hole through the screw on top near the earth pin (or inbetween for the 2 pin version) and force a 1mm stripboard pin in and glue in place. |
6th Mar 2015, 6:20 pm | #19 |
Rest in Peace
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Re: It's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
My method to improve the cable retention in a straight Bulgin cable socket, is by the use of adhesive lined heatshrink.
1. Wire the connector, fitting the fibre disc if available but with the round hole outermost and don't leave too much slack. 2. Thread a small nylon washer or similar insulating ring onto the cable sheath, ID as close as possible to the sheath diameter and OD just too large to fit through the hole in the cap, e.g. M8. 3. Thread on a 1 1/2" length of adhesive lined heatshrink, large enough to pass over the washer. 4. Shrink the sleeving with the nylon washer just inside the end, so that the very end of the sleeving traps it to form a flange 5. Align the cable cores with their proper terminal compartments and screw on the cap. The flange made by the washer will be attached to the cable by the adhesive and clamped by the cap. It is then almost impossible to pull the cable free, the individual cores cannot become exposed through the cap hole and you get a nice strain relief too. For larger cables (>0.75mm^2) it may be necessary to enlarge the hole slightly to accommodate the shrunk OD of the sleeving. |
6th Mar 2015, 9:14 pm | #20 |
Dekatron
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Re: It's a Sin: Bulgin 3 and 6 pin connectors for 240VAC?
Sounds good Lucien.
Have you got a picture for us? Nick. |