Low voltage lighting in 18th edition?

[Roger Hayter]

And isn't it a nuisance too? But it is still leakage to earth.

[Dave Plowman (News)]

Have your own way. So no difference between an ELCB and RCD.

[Roger Hayter]

I suppose that that is what makes RCDs useful.

[Johnny B Good]

Pendant lamp holders dangling from ceiling roses significantly reduce the risk of electrocution (fatal electric shock - usually the result of currents flowing across the heart, hand to hand or hand to foot paths) to a vanishingly low level (especially true in the case of BC lamp holders).

The safety aspect of BC lamp holders dangling by wire cords from ceiling roses is only compromised by damaged pendant cord insulation which is a whole new "accident waiting to happen" issue altogether.

The only 'scenario' I can envisage where such "Safety" can be compromised is when the 'Lamp Changer' has just stepped out of a shower straight onto a set of metal step ladders sans their plastic protective feet in a room with a bare and very damp concrete floor (the downstairs shower room itself?) to swap out a failed lamp whilst the lamp socket is still 'live' and fed via a fuse or mcb protected circuit unprotected against earth leakage faults.

The more usual scenario, a dry, fully dressed 'Lamp Changer' is unlikely to suffer anything worse than a shock localised to the unlucky fingertip that happened to stray deep within the empty BC lamp holder with perhaps a couple of painful burn marks on the end of said unlucky digit with virtually no shock current reaching the chest area.

Of course, this form of protection fails in the case of an old fashioned earth protected brass table lamp. However, since it's a fairly trivial matter to unplug such lamps so they are visibly isolated from any mains voltage, the 'Lamp Changer' can only have himself to blame in the event of a "Darwin Award" styled electrocution.

The statistics on UK 'lamp changing induced fatalities by electrocution' (0 BC and 1 ES associated deaths?) seem to bear out that the risk is extremely low in practice in spite of the theoretical risk case that can be made against either type of lamp holder or socket.

When a long established design and/or practice has proved itself to be acceptably safe for many decades (seven or more?), it's unlikely to be modified any time soon. Unless we start seeing a sudden spate of juvenile fatalities due to misuse of electric light sockets (which would be more a case of bad childcare rather than a deficiency of lamp socket safety), it's very unlikely that we'll see a change in the regulations to mandate "A Safer Lamp Socket".

At least whilst there are countless other 'safety issues' of much higher priority waiting to be addressed by the H&S executive, this one will remain firmly placed on the back burner. Who knows? Perhaps one day, when

*every* other potential death hazard has finally been dealt with, the death hazard embodied by the current lamp socket design might finally become visible above the death statistics 'noise floor' and 'Something done about it'. :-)

If you're waiting for a safer lamp holder or socket to materialise, I'd recommend against holding your breath in anticipation. Most, if not all of us, here will likely be long dead of natural causes without any need for asphyxia by the time such a design change is ever deemed necessary.

[ARW]

That's about all they are there for.

I have not done the job for a few years but sitting in the control room at the Keepmoat stadium and doing f*ck all but getting paid to watch a football match was a nice little earner. You had to be there 2 hours before kick-off, and stay an hour after the match finished. You got free parking and free coffee and tea.

I once had to fix the roller shutters on one of the bars, other than that I have done over 100 hour of getting paid to sit down and do f*ck all apart from watch football and some Rugby.

I booked a holiday when Elton John played there. It was either that or jump off a motorway bridge.

[ARW]

And will not trip if you stick your fingers in a plastic BC table lamp holder.

In a correctly working installation then what else it there other than earth leakage to cause the RCD to trip?

[Johnny B Good]

JOOI, did either of you suffer burns on your fingertips? Alternatively, since you don't make this clear as to whether you were shocked by touching a ceiling pendant light socket or handling a table lamp, did you suffer a shock through your arm and body as a result of providing a path to earth?

ELCBs and RCDs have been mentioned in this thread, asking how such protective devices can work in the absence of any path to earth such as atop a wooden step ladder when bridging the lamp contacts with a fingertip. The answer in this case is, "They don't!".

Fortunately, in this case, they don't have to (work, that is!) since the luckless victim does all the necessary work of 'protective action' either by rapidly withdrawing their digit or else by dragging the lamp cord out of the ceiling rose or even snapping it in two as they spring off the ladder, howling in pain with nothing worse than a bruise or three to show for their embarrassment.

I dare say that there *have* been a (mercifully) few fatalities as a result of injuries consequent to such electric shocks over the many decades of DIY lamp changing to date, presumably a statistically insignificant number to warrant a 'fresh look at the problem'.

I'd imagine most such fatal cases would have been the result of failing to take account of the higher than usual risk of death by injury resulting from falling from a greater height such as from a set of steps on a landing at the top of a flight of stairs and similar hazardous locations where such precautions should have been undertaken anyway, irrespective of the electric shock hazard of changing out a lamp.

What few of the remaining fatalities in more prosaic settings (a living room lamp changing exercise) resulting from injuries consequent to a fall from a ladder (step or otherwise), even when electric shock was proved to be the trigger, have probably been determined to be a fatality due to 'unsafe ladder working practice' rather than a lack of safety in the design of the lamp holder or socket itself.

Compared to all the other hazards associated with changing a lamp, the risk of actual electrocution is vanishingly small, assuming no other obvious electrical deficiencies such as damaged insulation or loose bare wiring.

The humble lamp socket is, imho, safe enough for its purpose although the ES types are slightly less so and the adoption of ES over BC fittings for GLS lamps, other than in exceptionally appropriate usage cases, is a practice that ought to be actively discouraged in spite of Ikea's determined efforts to introduce it as a de-facto standard via the backdoor of selective marketing.

[Adam Funk]

I'm pretty sure such things exist (e.g., with spring-loaded bits that break the contact when the lamp is removed), but they are slightly more expensive to manufacture.

[Graham.]

steady 245-246 here. 3v drop on the incommer when the 10.4kW shower is running.

[Graham.]

And current passing through a child's fingertip is most unlikely to be fatal, but will hurt like hell and learn them not to do it again!

[Graham.]

Exactly that plunged me into darkness once while working on the lighting circuit in my loft. I had switched off the upstairs lighting MCB, but didn't realise a E-N short could still trip the RCD and kill the inspection lamp I had on an extension reel.

[Scott]

Thanks. All the myths about electricity are gradually being dispelled.

[ARW]

[damduck-egg]

If there had been a problem I would have thought it may have been revealed back in the era before power sockets were fitted in many premises and the pendant lamp fitting was the only source of electric in the room. Removing the lamp and connecting the flex of an Iron or other small appliance using a bayonet plug was common, some users used a Y piece with two outlets that allowed the lamp to remain in place which did leave unprotected pins when the appliance was disconnected. Some more expensive versions did have switch.

G.Harman

[charles]

you could buy them in Woolworths!

[damduck-egg]

Hoover suppled a version that converted the pendant to a two pin socket .

There is a photo of a couple at the top of this page.

The socket contacts look even more likely to touched by a wayward finger than the bayonet pins alone.

G.Harman

[tabbypurr]

low hanging pendant

yep.

NT

[Graham.]

He knows full well, his point is RCDs do not work by detecting earth leakage directly, and he's right.

[Graham.]

I reckon a toaster is the most dangerous domestic appliance for it's shock potential* in normal operation.

*SWIDT?

[Graham.]

IRTA low hanging pedant.