Thorn VR 100

The VR 100 range of recessed light fittings from Thorn appeared in the late 1960s / early 1970s and came with diffusers typical of the period; these included a plastic louvre, a "clear crystal glass dish" two sizes of "satin etched opal glass bowl", a "Scatterlight disc" and a "pin-hole attachment" - this version is of the former type. Although designed for a maximum 100 W GLS lamp (hence, the "100" part of the name), the versions using glass diffusers could accommodate an 80 W mercury lamp instead, with the lamp control gear installed remotely. VR 100 (and the larger VR 200) fittings could be seen in many areas of my primary school, although most had lost their diffusers (or they had been removed) by the time that I knew them. This particular example is unused old stock found on eBay, and dates from 1979.


The fitting arrived in its original box. Although not stated, the plastic louvre attachment was packaged with the fitting.


 A very faint inspection date stamp of September 1979 can be seen above "VR 100 BC". Not a lot happened that month.


The fitting is based around a spun aluminium reflector measuring 209.5 mm (8.25 in) wide and 127 mm (5 in) high. When installed in a ceiling, only the rim would be visible. A 184.1 mm (7.25 in) hole would need to be cut in the ceiling, in order to accommodate the fitting.


Unlike modern recessed fittings that employ spring-loaded handles to hold them in place, this uses three adjustable clamps that are each secured by tightening a screw on the inside of the reflector. The clamps press against the  top side of the ceiling material, and because the rim prevents the fitting from being pushed up into the ceiling completely, the unit is secured.


A thin aluminium strip supports the lampholder and also acts as the fitting's earth connection point. The strip is pop-riveted to the reflector; this connection is positioned above where the lamp would be sited and therefore would be obscured from view when the fitting was installed.


A second inspection stamp exists on the outside of the reflector - again, this confirms inspection occurred in September 1979.


The louvre consists of four concentric circles linked by three spines; the circles are slightly stepped, with the innermost and smallest circle protruding the furthest forward.


The spines also hold three plastic hooks that allow the refractor to clip into place.


Looking "up" into the inside of the reflector, we see the three narrow protrusions to where the louvre attaches.


With the refractor placed into the reflector, we see that the innermost circle matches the position and size of the indentation used for lamp focusing. The refractor is a surprisingly poor fit and is simply placed on top of the protrusions. By comparison, the other diffuser options attach to these in the traditional "bayonet" method.


Close-up of the means of securing the fitting to the ceiling on the left, and the diffuser holding clip on the right (or at least, one of both).


Sandwiched between the lampholder and another of the clips is the product label. This would probably end up peeling off after a while, owing to the reflector becoming hot during use.




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