A Few questions here,
When was the ES27(?) lampholder introduced to your country?.
What types of fittings are they pre-dominantly used in?.(Currently)
What is the maximum wattage of lamp, allowed
in your fittings using these lampholders?.
Are there Regulations to require that the Phase wire, goes to the centre terminal of the l/holder?.
Your thoughts please- :

>When was the ES27(?) lampholder introduced
>to your country?.

When bulbs were introduced. Guess why it is called Edison?

>What types of fittings are they predominantly used in?.(Currently)

All large fittings that take bulbs. (Including mercury lamps) The smaller ES14 is also popular. (In a few cases bayonet cap sockets are used as they're non standard, preventing theft.)

Only fittings intended for low-energy lamps of various types use special holders. These lamps are often horribly expensive.

>What is the maximum wattage of lamp, allowed
>in your fittings using these lampholders?.

Plastic: 60W

>Are there Regulations to require that the
>Phase wire, goes to the centre terminal of
>the l/holder?.

No. For wall mounted switches, you are required to switch the phase wire, not the neutral. (You may of course switch both if you want to.)

[This message has been edited by C-H (edited 11-26-2002).]

Same answer as Sweden.
Metal ones ? old ones seem to have no limit at all, didn't have the chance to take a look at a new one.
Used almost everywhere, except for small table lamps, etc (ES 14), only exception being fluorescent tubes and metal halide elements. Compact fluorescents with ES 27 (E27 here) screwshell are pretty common.
It is, as far as I know, strongly recommended but not mandatory to wire the phase to the bottom contact.

In South Africa, the standard sized Edison Screw fittings are used exclusively on spot-lights and flood-lights as well as some imported free-standing lamps like angle-poises. These latter lamps were obviously the easiest for me to adapt when I moved to the USA. I have no idea when they were first
introduced into South Africa but I would suggest at the beginning of electrical time. I would think that this connection method pre-dates the bayonet cap which is by far the most common light-bulb configuration in South Africa.

Wandering slightly off-topic ...

Two combined lamp and ceiling fans were installed in my new house in South Africa, they were made in China (what isn't!?) and had Edison screw fittings for the lamps. One of the first jobs I did after moving in was to pull an additional wire into the conduit between the unit and the switch box so that, with an additional switch, I could separate the working of the fan and lights. These had been combined by the installer.

My experience with this brings to mind discussions on international wiring standards presently being undertaken on a parallel thread. The unit was 230V (and labeled as such) but had in addition to the green/yellow earth wire had a blue, a black and a white wire. This was very unusual for South Africa and confused me. It had also confused the installation electrician as he had combined the black and blue wires on the fan unit and connected them to the black neutral wire in the ceiling box and the white wire was connected to the red feed coming in from the switch. I have seen red, brown and white wires used as the switched feeds in various places around the country and so at first glance it looked OK but the combined neutral did look very odd.

It was of course wired exactly the wrong way round with the shell of the Edison Screw live when switched on. It was only after having visited the United States that I could see that North American wiring colour conventions had been used on a 230V, Chinese made, South African fan/light fitting. These colours were exactly opposite to our conventions.

A tester soon sorted out the mess and to my (then) surprise white turned out to be the common neutral, black the feed to the fan and blue the feed to the lamps. With North American eyes it now looks perfectly correct. Still at the ime .... The other fan had been installed exactly the same.

I am surprised that these units got passed the South African Bureau of Standards and were allowed to be imported as coded. The grey market I assume.

The standard ES fitting has been around a long, long time, but for some reason Britain opted to use the double-contact BC (bayonet cap) type for most standard domestic bulbs.

The ES bulb is found here in some fittings, probably more so these days with the sale of the same fictures throughout Europe.

IEE Wiring Regs. specify that the live/hot shall be connected to the center contact.

As for the maximum rating, it depends upon the construction of the lampholder and the fitting in which it is located.

Paul,
A few years ago,a customer, had me remove a lamp,for him for replacement,from a fitting in a shop, this was an internally-silvered lamp, with the bottom part of the bulb glass silvered, upon withdrawing it, I noticed it was not a standard lamp, it was a BC22 type base, but it had Three location pins on the sides of the brass cap, spaced at 120 degrees,looking at it from the top.
Can you or anyone else please tell me, how
common,this type of lamp configuration is?,
as I had never seen it before then,nor have I seen it since.
Strange, but true.

Trumpy,
I know the type of base you mean. It's very rare, but I've run across it a couple of times; I think they were the "Fireglow" type of bulb, such as might be fitted in a domestic heater to give the coal-effect.

Very difficult to obtain replacements for these, so if I came across another I think I'd recommend replacing the holder with the more usual BC type.

Thanks for your advice, Paul, as I said this occurred a few(4) years ago, I simply changed over the existing fitting to a R80ES
spot fitting, no tears, no problems.
Tried to source the bulb,at the time, no-one even knew it existed.
Go figure!

I remember reading on some lightbulb collector's website (yes there are people who collect old type lightbulbs) who said that the London Tube uses a special type of bayonet fitting for their signal light bulbs (to discourage theft).

Apparently the bulbs have three locking pins on the base instead of the usual two. Not that there's probably any trouble with taking a needle file and obliterating the offending pin.

In addition to your lamp cap details,

our local coucils street lighting gangs install an MBFU 125 watt lamp in a three pin baynet type cap as standard, in a few areas
only now, ( most are being changed for either High Pressure Sodium or Metal Halide)

The MBFU type lamp is a ballast free mercury lamp that has an average lamp life of 10,000 hours plus, then the lamp starts to fail and lamp output goes down,
a good reliable lamp and has its uses in other places as well, ( we still have a few around one of our customers sites, but they are getting on a bit now, the lamps mot the customer).

I found a picture (and the website it came from) of the London Underground bulb I mentioned:



And here is the website: http://electriclights.tripod.com/bulbs/londontrain.htm

According to the site, the bulb operates at 100 volts.

[This message has been edited by SvenNYC (edited 12-02-2002).]

I'm not sure about the pin spacing on this special bulb, but the ones we were talking about above have the three pins spaced 120 degrees apart around the base. A normal BC bulb has its two pins opposite each other, so just filing one pin down wouldn't work.

I wonder how long this base has been used by London Transport?

Anyone else (probably from the U.K.!) remember seeing an old Arthur Askey movie where he's sleeping in the Underground station (as many did during WWII) and then opens up a signal lens at the end of the platform to run his electric shaver?



[This message has been edited by pauluk (edited 12-02-2002).]

Paul,
I have actually seen that film, through some cruel twist of fate, I think that it was part of last years Christmas-New years fare on TV over here.
Not expecting anything better this year either.
Interesting comments on the 3-pin BC lamp though, it sounds to me to be like a lamp manufacturers attempt to future-proof thier
investment.
They must have been in cahoots, with a lamp base manufacturer, as mongrel fittings like this don't do any of us any good, in years after the fittings and lamps have died out.

I've got a few suggestions for Edison lampholders.

1.) They should be made out a heat resistant plastic, so that it is safe to use 100W bulbs.

2.) Bulbs should not be allowed to exceed 100W. With 1.) this would much reduce the risk of fire in lampholders. Higher wattage bulbs should have a special incompatible holder.

3.) The lampholder should be designed so that the wires have a higher degree of protection from the heat generated by the bulb. E.g. increased distance between bottom of bulb and terminals.

4.) The lampholder should be designed in such a way that the bulbs only becomes energized when it is almost fully screwed in.
This to prevent people from touching the base of the bulb when it's live.

Is this Christmas wish list realistic?

OT sorta...
Sven — the London Underground lamp has very interesting filament construction. If they just could bring out four terminals in the base, it could be a truly “universal/international” version, usable in 100- or 200-volt service—sort of...as series/parallel connected? :-)

C-H:

re. heat resistant plastic lampholders. I'm more of an old fashioned guy. I would prefer porcelain. It doesn't deteriorate at all with high heat.

However if you're going to use plastic....the best plastic for a lampholder is thermo-set phenolic (Bakelite) which is that brown plastic that was so ubiquitous 50+ years ago.

It's still widely used here in the USA and also in Asia for wiring devices. I wouldnt recommend melamine (white) and certainly NOT urea.

Both of these deteriorate and discolor under high heat. Bakelite does not.

---
Bjarney:

Apparently the reason for the double filament is that if one of the filaments burns out, the second one takes over. That way the bulb lasts twice as long and you don't have the problem of a disabled signal light in a tunnel holding up train service. The second filament holds up until the tunnel maintenance crews make their normal inspection rounds I guess.

And also crews don't have to go down into those tunnels to replace bulbs that often, which from what I've seen here in New York, is no piece of cake (what with the rats, water, 600-volts of electricty, crack-heads and heroin addicts and that ever present soot and dust that gets in your lungs and made my silver ring go BLACK when I walked into one of them).

You'd actually need only three terminals do to this. A lot of miniature vacuum tubes (e.g. 12AX7/ECC83 etc.) had such an arrangement for their filaments, enabling them to be wired for 6.3 or 12.6-volt operation.

Concerning plastic lampholders: I've seen many abused ones which crackled, discolored and stank like old fish. Personally, I only buy metal ones, but I've to deal with the cheapest imagineable plastic ones because I'm in charge of changing bulbs in our appartment building, and the new basement lights that replaced the 1914 porcelaine ones are hardware store type IP 44 and fall apart upon touching them (just had the pleasure of dealing with two of them today, one fell apart completely). One of the porcelaine ones was broken and dangerous, but the other one would probably have lasted forever (but it was a pity to have the beautiful thing with it's white glass shade hanging in the basement, just imagine someone with a ladder passing by and *smash*..., so when we rewired I took them down and salvaged them)
Quality IP 44 fixtures here have a porcelaine socket inside a plastic and glass enclosure, not just a tiny backstabbed plastic monster. At least they supplied silicone tubing to protect the wires from heat.

Ranger:

You're lucky you didn't get shocked when the socket fell apart on you.

Does your dad own the building?

If so, tell him to stop being such a Scrooge and go out and buy lamps with porcelain sockets instead of the cheap-crap!!! hehehehe

P.S.: Bakelite (when overheated) smells like carbolic acid. It will break down under VERY high heat, but it will not melt. It disintegrates instead.

If you're using 100-watt bulbs and above in a base-up fashion, I would go for porcelain sockets. They're designed for that sort of use, I think.

As for metal lamp-holders, I hate them. The paper sleeve always dries and crumbles because of the heat from the bulbs. I don't know if the European-market metal ES-27 holders have cardboard sleeves to insulate the mechanism from the metal shell, but the American-market ones do. And you see lots of old table lamps with crumbled paper insulators (requires one to replace the lampholder). I always replace them with Bakelite-shell lampholders.

By the way, can you take pictures of the old porcelain fixtures you took out?

[This message has been edited by SvenNYC (edited 12-24-2002).]

So noted, Paul. Too used to ac magnetics, I guess.

--Bjarn

The socket itself didn't fall apart, it only fell out of the fixture. (only snaps in place). The house (8 appartments + finished attic, built in 1914) belongs half to my dad, half to my uncle, my uncle does all the paperwork and is in charge of the repairs. As it is almost impossible maintaining a rental building without throwing in much of your own money your only chance is to take what you get. Furthermore, hardware stores rarely ever sell quality stuff, and buying at an electrician's is much more expensive. Hence the cheap fixtures.
Our metal sockets don't have that evil cardboard. Old ones just have more space between screwshell and outer shell and a porcelaine ring that goes betwen screwshell and outer shel seperating it and covering the exposed part of the bulb's thread. Newer ones just have an outer base contact instead of the large screwshell, and the thread holding the bulb sits on a porcelaine base in the outer shell. Thus these sockets are almost everlasting, just consisting of porcelaine and metal.
Maybe I can take pictures of the old fixtures, but it'll take some time, as I don't have a digital camera.
One of them still loked like new, the other one had a broken screwshell, missing shade and some other missing parts.

So I gather they look something similar to this, right Tex? However it has a plastic instead of a ceramic sleeve.

(Image from http://www.tlc-direct.co.uk in the UK)



You're right!!

They do look better than the American-market ones. Maybe someday I'll get some for when I rewire some table lamps...but for now (unless I need to use the metal ones) I'll have to stick with the Bakelite shell ones.

[This message has been edited by SvenNYC (edited 12-26-2002).]

Yeah Sven, that's it. The shape is a little bit different (no wonder, they're about 60+ years old, one of mine is pre-WWI), but the basic setup is exactly the same.

Aren't American bulbs E(S)26 and European E(S)27?

No, I don't think so. I used our bulbs in American sockets without any problems.