Bayonet vs screw-top bulbs

[Andy Dingley]

MK make one of these for pendants - quite big, but seems robust.

OTOH, I'm now replacing a number of recently installed BG switched brass and plastic lampholders in desklamps. They're so badly made that the switch actuator bar is breaking, owing to bad materials. It looks as if it's paxolin, but with no linen or paper reinforcement (quite translucent) and horribly weak. The design for combining switching and isolation unless pressed is a right bodge.

I'm also unconvinced that there's much benefit to doing this anyway. What's going to be pressed into a BC socket to touch the contacts, without risk that it will push in enough to make contact too? If we're that concerned about finger contact, we should use GU10s

[Bob Eager]

Some of the higher quality ones have a mechanical linkage. The power is applied when the bulb is rotated into place; there is an inner 'cylinder' of metal or plastic that gets rotated to allo the bulb pin to enter the arm of the 'J'. Or there's a sliding shield. MK Shockguard holders are like this, ISTR.

[docholliday]

That would seem to square with the choice of connector for the larger sizes of GLS bulbs, which all seem to be screw connection - E27 up to

500W, with GES (E40?) for larger sizes (and some 300 and 500W bulbs too). I'm not sure what the largest sizes were - the largest one I've handled is a 1500W, though the documentation on the box appeared to imply they also made a 2kW bulb.

-- Mike

[Tim Watts]

I've got an Ashley one and it's indistinguisable from any other fitting. Quite clever - requires the bulb being inserted and turned to turn a husing which then makes the pins live - so sticking fingers in and pressing the pins won't buy you the farm either.

[Skipweasel]

I'd argue with "many". Possibly many /new/ sockets are like that, but the installed fleet are probably on average several decades old.

[Skipweasel]

It was, last time I did it. I was about seven or eight and I well remember being too embarrased to tell mum why my arm hurt so I told her I'd fallen over and banged it.

Dinnarf ache.

[Bob Eager]

Agreed. I was thinking of new ones, in terms of which one to choose when fitting, I guess.

[Mike Clarke]

The main threaded part is isolated from the mains on all the recent ES sockets I have. The threaded part of the bulb makes contact with a separate small metal contact on the side near the bottom of the socket. So even if it's wired incorrectly the live part is no more accessible than the centre contact.

[GB]

I had a good squint inside my Anglepoise lamp before posting, and it has none of this la-de-da safety stuff. Obviously produced when men were men and boys were electrocuted. :)

[Andrew Gabriel]

No it isn't - you can't get a good enough contact on the pins. You'll certainly get a jolt, but not "quite nasty." You are more likely to generate a path from one pin to the other, or to the earthed sides, than you are to a separate ground. Given the very widespread use of BC holders for decades and no recoreded electrocutions, they are grandfathered as exempt from IP2X requirements of PAT testing (can't touch a live part).

OTOH, there are several electocutions from ES holders, most commonly when the threaded contact is live, and the person grips the lamp to [un]screw it and makes good contact with the threaded lamp base. That shouldn't be possible in the UK with a polarised mains supply and requirement that the tip is the live connection, but it is possible in most countries where they're used. There are newer variants which effectively disconnect the thread as soon as you start removing the lamp, by having a separate connection and not using the whole lampholder thread area.

[Ghostrecon]

did the same in a hallway pendant which was missing its bulb (neighbours house) as i was coming down the stairs - memorable enough for it to last

45years (the memory - not the shock)!

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Timothy Murphy saying something like:

That's just them - they source their kit on the Continent. No shortage of BC lamps anywhere else in Ireland, that I see.

Easily available - google for bayonet to ES converter or vice versa and you'll find both types, usually around £1.50 (in the UK). They're also available in Ireland if you poke around a bit.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Andy Dingley saying something like:

There was a flood (still is) of those crappy ones on the market a couple of years ago. A direct copy of an older one I have, which is made in Britain. The nasty ones were knocked out in China. I'm actually a bit concerned about such cheap and nasty fittings leading to fires and now make sure they don't get through my door.

[Dave Liquorice]

screw

BTDTGTTS aged 6. B-)

But it's not so easy to contact the terminals of a BC socket with a bulb in place. Old metal construction ES sockets wired arse about face you could touch (no live) the metal thread portion no problem. Modern ES sockets tend to be ceramic or plastic with the outer connection a bit of bent tin near the bottom.

[Mike Rogers]

I have no idea why my newsreader has decided to download this post from

11 years ago but I couldn't resist this reply!

Mike