Cleaning bulb holders

[PaulR]

Our church has chandeliers converted in the distant past from gas fittings to electricity. The bulb holders are brass but as far as I know they were not replaced when the building was rewired several years ago so they may well date back to before the war.

Several bulbs (low energy types) appeared to have failed so I bought a complete new set as they were rather old. On going round to fit some this morning I have discovered that actually many of the bulb holders themselves have poor contacts. The contact pins themselves move freely and appear clean at the ends so I am thinking that they have tarnished badly in their sliders and so are making bad electrical contact in the fitting itself. There are 60 of them altogether and they are very high up so replacing them would be a job for a professional. Before I recommend this does anyone know of any cleaner I could try in them? I was thinking of Deoxit or similar, or is it likely that the problem would be beyond that?

Thanks Paul

[pmmunro]

Paul,

What is the orientation of the lamp holders? If they are vertically downwards, i.e. with lamps below, it is very likely that the compression springs which act on the contacts have lost their temper due to heat from the lamps and are now very weak. Even if they are vertically upwards the springs are likely to have weakened so that cleaning is unlikely to restore an effective contact.

As you are able to reach a sufficient height to change a lamp, is it possible to remove a sample lampholder to make measurements for a replacement?

If the chandeliers were converted before 1939, it's almost certain that the wiring is due for replacement so that should be done too.

I take it you mean 60 lamps, not 60 chandeliers so how many chandeliers are there?

Professional refurbishment is likely to be very expensive due to the time involved and I would think you would be very lucky to find a general electrician both willing and competent to do it.

At our church we do a lot of this sort of work from our own resources and have acquired the means to do it over several years, e.g. Insulation tester, portable appliance tester. Are you able to hire or borrow access equipment which would allow you to take down the chandeliers, put temporary lighting in place, recondition the chandeliers and finally replace them? Another option is to recondition them on a rotating basis but that means having the access equipment on many separate occasions.

A great deal of the work on older buildings is prohibitively expensive at commercial rates but if competent volunteer labour is available, you do a great deal for much less cost.

PMM

[broadgage]

I rather doubt that a poor electrical contact between lamp and holder is to blame.
Mains voltage at low currents is fairly "determined" at finding its way through oxidised or dirty contacts unlike low level signals in electronic equipment.

I consider it more likely that the springs in the lamp holders have lost their effectiveness due to age or heat.
If the lamps are cap upwards then the springs will have previously got very hot if high wattage filament lamps have been used.
If the lamps are cap down, then over many years it is likely that the weight of the lamps has compressed the springs, especially if first generation CFLs with an integral copper/iron ballast have been used.

With the lights turned on, try pushing any sound but unlit lamps a little further into the lamp holder, this should make contact even if the springs are weak and no longer fully extend.
TAKE GREAT CARE IN DOING THIS DUE TO THE RISK OF ELECTRIC SHOCK. I WOULD WEAR LINESMANS INSULATING GLOVES if handling live lamp holders in doubtful condition, and at a height.

Alternatively, take a suitable known good lamp and slightly build up the contacts on the base with solder, such that they stand proud by say 2mm more than normal.

If the above tests show weak/not fully extending lamp holder springs then you will probably need to replace the lamp holders.
Take the chance to examine the internal wiring of the chandeliers and replace if doubtful. Although the premises have been re wired, the internal wiring within light fittings is often missed.

I have seen old gas (or oil or candle lit) chandeliers converted to electricity in various potentially unsafe ways, please take great care.

[WreckTangle]

If the lamps are verically downwards, then heat damage to the wiring in the bulb-holder is also a possible cause. I fixed a similar fault in my local church some years ago by simply removing a couple of inches of flex and re-making the connection using the original bulb-holder.

[PaulR]

Thanks for the replies.

The lamp holders are at an angle of 45 degrees which doesn't help. Compression of the springs due to the weight of the lamps was my first thought but the offending ones still seem quite springy. I tried WD40 in case any had got stuck but his has not helped. I tried pushing the lamps in against the springs but that did not work for most of the dead ones either. Turning the lamps in the holder not far enough to remove them did help, hence my thought that some sort of corrosion might prove to be the problem.

The whole church was rewired about 20 years ago but I understand that the fittings on the chandeliers were not replaced so it may be that the wiring was not done either. I daren't think of the condition it will be in by now if it wasn't replaced. I will try to find the records from the time in case any specifications are still there. I sincerely hope that the chandeliers were earthed, but I was careful only to hold the glass lampshades when I was fiddling with them! They are so heavy that you can change the bulbs pushing only against the inertia of the fitting itself. There are 10 of them with 6 bulbs in each. It really needs a proper platform to do any work on them or to inspect them at all and then there are pews in the way of most of them.

I retire in the summer and know a hire shop owner so I think that the way forward must be to borrow a platform, remove a holder from one of the more accessible chandeliers, hope that the wiring is modern, and investigate whether replacements are available. They are so very big and heavy that I doubt whether they could viably be taken down.

Many thanks

Paul

[emeritus]

If it's just a question of the ends of the contacts needing a clean, then a 12V mini drill such as a Dremel or a Minicraft, fitted with a wire cup brush, can work wonders. I used to use my Minicraft to keep our old Ever Ready cycle lamps in good working order, as the contacts were for ever tarnishing.. The sprung contacts of a BC lamp holder are readily accessible and you can use a miniature drill like this with one hand. A 12V drill can be powered from a small 12V battery, so no problems with getting power up a ladder or tower.

The threads for brass lamp holders in the UK have long been standardized as 1/2" brass thread (26tpi), so replacing old lampholders with new might not be a problem. However, in my Victorian and Edwardian GEC catalogues, lampholders were available screwed with either brass or BSP (gas pipe) threads, so it is possible that a chandelier converted from gas operation might have been converted using lampholders screwed with Gas thread.

[PaulR]

I am coming back to the idea of tarnish being the first thing to eliminate. Our several sets of Christmas lights are connected to bulb holders via bayonet connectors. This morning one set would not come on and the cause turned out to be the switch on one of the bulb holders which is only used for a relatively short period each year. Cleaning the contacts with emery paper has made it work again.

I think that the next thing to try will be cleaning then up as far as possible with a Dremel.

Paul

I think that the next thing to try will be cleaning them up as far as possible with a Dremel

To save getting bored only the tips of the prongs would need cleaning (if that is the problem). It may be that the wire clamping screws have become loose, shouldn't be hard to give them a tweak while up there.

[Nickthedentist]

If these are bayonet cap lampholders along the lines of these:

http://www.bitofbrass.co.uk/ekmps/sh...%5D-2319-p.jpg

then be aware that they can cease to work if the portion which accepts the lamp has become misaligned with the sprung terminals and/or base, such that when the lamp is correctly inserted, the sprung terminals rest on the wrong parts of the lamp's base.

Dismantling and careful reassembly may be all that is required.

Nick.

[PaulR]

Originally Posted by Nickthedentist

Dismantling and careful reassembly may be all that is required.

...and that would explain why they work when the lamp is partly rotated of course! Good point, Nick.

Merlinmaxwell - I can see boredom setting in very early with this project! At least there is a decent sound system to listen to whilst I am doing it.

Many thanks

Paul

[emeritus]

In the 1960's I found a very old brass lampholder of that type in my dad's box of electrical odds and ends that I could never get to work properly, however carefully I assembled it, as the bulb would light when just resting in the holder, but not when rotated to engage the bayonet detent. Years later I found out that there used to be a BC-type fitting where the bayonet pins were at 45 degrees to the bayonet detent instead of 90 degrees, and that my holder must have been for this obsolete type of lamp base.

[Hunts smoothing bomb]

I'm inclined to agree with Nick as I have come across this many times before.

Cheers

[alanwin]

A fibre-glass scratch pencil is very good for cleaning basic contacts like these, use them like a propelling pencil to remove oxidation. The debris is an irritant so keep it off skin. They are also used to remove rust etc from car paintwork stone chips prior to touching up. Ebay or Maplin http://www.maplin.co.uk/p/abrasive-f...s-pencil-kr61r

Alan W

[Nicklyons2]

I've come across quite a few instances where the ends of the wiring into the lamp holder was the problem - arced, corroded or burnt away. Trimming back an inch (sorry 25.4mm nominal) or so on the wiring and cleaning out the inside of the terminal using the end of a needle file has generally sorted things. Not a lover of WD40 by the way - not in these applications.

Trimming back an inch (sorry 25.4mm nominal)

No need to be sorry, the inch was redefined in about 1960 as exactly 25.4mm (to build Concorde apparently) so it is a metric measurement now. Back on topic, yes the last inch or so of wire can get quite tired.

[Brigham]

If the holders are at 45 degrees, then they have not been direct replacements for gas burners, which are either upright or inverted. In which case BSP threads will probably not be found.
If the plunger springs are weak, it may be possible to fit a complete porcelain base from a new brass holder. They appear to be very similar, and would eliminate the thread question, and also maintain the appearance of the fitting.
I'd love to see this installation. Churches are a good place to look for pre-Great War gas and electric brassware.
Any chance of some pics?

[PaulR]

Thanks for the replies all. I am busy at work at the moment so won't have a chance to look at them again for a while. Here is a link to some photographs on the web site http://www.emmanuelsouthport.org.uk/...lery_id=9&pg=1

The second down on the right gives a good idea of the chandeliers. They are large "blacksmith made" wrought iron affairs. I wonder whether the gas fittings were originally inverted and were cut off for some reason when converted to give the 45 degree angle.

I can take a close up photograph if anyone would like one. There are various bits of cut off gas pipes in and out side the building. There were once very decorative gas lamp standards around the grounds but sadly only the stumps of these remain after they were removed during the war.

[WreckTangle]

If or when you get around to having a proper look at these be prepared for a rat's nest of ceramic thimble connectors in the central hub. Whilst generally pretty reliable, they are no longer approved for use in this country. If you're lucky there may be room to replace them with modern terminal blocks.

[emeritus]

Is it just the ceramic types (I knew them as "Scruits") that are no longer approved? I was surprised to see that the latest "Screwfix" catalogue has several types of "Twist-on" connectors that seem to work in much the same way, rated at 450V and 600V, and said to be suitable for joining wires of between 0.5 and 6 sq. mm according to type.

[PaulR]

Just a belated finish to this one. I finally managed to get up to some of the chandeliers today and the ceramic fittings are indeed twisted in the outer brass holders. It is just a matter of taking them apart and putting them back together now!

Paul