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A fitting for four Lamps No. 12... (1 spare). They were used outside
offices of P.O. officials to indicate:-
OUT, ENG.,
IN
(Red) (Yellow) (Green)
Includes:-
1 x Cap, Lamp No. 6.
Drawing - 91354 and 91378.
P.O. ENGINEERING DEPT.
ENGINEERING INSTRUCTIONS
MISCELLANEOUS
GENERAL
C 3001
Issue 1, 26.9.38
LAMP INDICATORS FOR OFFICES
1. General
This Instruction describes the Lamp Indicator scheme which has been designed
for fitting outside the office of a higher official, when desired, to
indicate by means of lamps, coloured red, yellow, and green, whether the
official is out, engaged, or in, respectively. The scheme has been
introduced primarily on account of the publicity value it has where
officials frequently interview members of the public, but additional lamp
appearances of a more practical value may be provided in the messengers'
lobby, and adjacent to the desks of the personal clerks or in other
positions which are conveniently visible to subordinate staff.
2. Apparatus
Items of apparatus which have been specially coded are as follows:-
-
Lamp Fitting No. 3
-
Lamp Fitting No. 4
-
Switch, Tumbler No. 29
-
Transformer No. 124A
Item (a) (Fig. 1) is placed adjacent to the personal
clerk's desk, and in the messengers' lobby or any other position(s) desired;
Item (b) (Fig. 2) is fitted outside the office door of the higher official.
Item (c) (Fig. 3), the switch by which the signals are operated, is placed
adjacent to the official's desk.
Item (d) is rated at 400 W., 22V., and will therefore supply a maximum of 40
lamp appearances.
3. Other items associated are:-
-
"Lamps No. 12, 22V.," red, yellow and green
-
"Tablet, Polished Hardwood, No. 1"
-
"Label No. 23, white," engraved OUT, ENG, IN (see Fig.
3)
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"Cut-outs No. 1, n/n"
-
"Box, Service, E.L., No. 0" or "Switch, Tumbler No. 2,"
4. Wiring
The system should he wired to Diagram TL 2646 and POWER, Lighting, B 3015,
with "Cable, E.L., I.R.V. Core, 250V., 0002 sq. in." or "Cable, E.L., 250
V., 0002, Black or Red" in conduit. The wiring on the supply side should be
in accordance with I.E.E. regulations for power.
5. Alternative fitting
A less-comprehensive light signal, which has found favour with D.M.s,
Surveyors, etc., is the lamp fitting shown in Fig. 4. The white opal glass
shade - in the form of a cube - contains a low-wattage lamp, usually
coloured red, which is connected to the normal lighting supply and
controlled by a tumbler switch adjacent to the official's desk. This fitting
has not been coded and may be purchased and fitted locally.
Reference:- POWER, Lighting, B 3015
FIG. 1 - Lamp Fitting No. 3
FIG. 2 - Lamp Fitting No. 4
FIG. 3 - Switch Tumbler, No. 29
(Tumbler Switch No. 29 mounted on a polished hardwood tablet No. 1, with
label No. 23)
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