Improvements in Apparatus for Connecting Branch Circuits to Electric Mains.
Year: 1899

page_text: Date of Application, 5th June, 1899
Complete Specification Left, 5th Mar., 1900-Accepted, 5th May, 1900
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Connecting Branch Circuits to
Electric Mains.
We, CALLENDERS CABLE & CONSTRUCTION COMPANY, LIMITED, and THOMAS
OCTAVIUS CALLENDER, Electrical Engineer, both of 90, Cannon Street, in the
City of London, do hereby declare the nature of this invention to be as follows:-
According to this invention each service box is provided with a special form
of plug switch and a fuse.
The bared ends of the negative conductor and of the neutral conductor are
respectively connected together inside the service box by bridge pieces in the
ordinary manner but in place of both the bridge pieces being also connected to the
terminals of the branch or consumers circuit as is usual only one of them is so
connected the other being connected to a contact ring whilst the other terminal
of the branch or consumers circuit is connected to a second contact ring.
In order to close the circuit a plug is inserted into these rings. The plug is
made in two pieces of non-conducting material fitting one within the other and
each carrying a conducting band. These bands respectively fit the contact rings
and are connected by a fuse wire which lies within the outer part of the plug.
The positive conductor which is usually the inner conductor in a triple cable
can be similarly connected to the circuit through one of the conducting rings.
In this case the bridge piece connecting the bared ends of the negative conductor
is not connected to the circuit.
1000
CALLENDERS CABLE & CONSTRUCTION COMPANY, LIMITED,
The Common Seal of Callender's Cable
& Construction Co. Ld. was affixed
in the presence of,
P.
GEORGE HIV. ELLIOT, }
Directors.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Connecting Branch Circuits to
Electric Mains.
We, CALLENDERS CABLE. & CONSTRUCTION COMPANY, LIMITED, and THOMAS
OCTAVIUS CALLENDER, Electrical Engineer, both of 90, Cannon Street, in the
City of London, do hereby declare the nature of this invention and in what manner
[Price 8d.1

page_text: the same is to be performed to be particularly described and ascertained in and
by the following statement:-
.
According to this invention each service box is provided with a special form
of plug switch and a fuse.
Figure 1 is a vertical longitudinal section of a service box constructed according
to this invention. Figure 2 is a plan with the cover and plug removed.
Figure 3 is a vertical section (to twice the scale of Figures 1 and 2) on the
line 3-3 Figure 2.
°
The ends of the negative conductor a and of the neutral conductor b both bared
of their insulating material c are respectively connected together inside the
service box by bridge pieces de in the ordinary manner but in place of both the
bridge pieces being also connected to the terminals a¹ b₁ of the branch or con-
sumer's circuit as is usual only one of them e in the drawing is so connected to
the terminal b¹ the other d being connected to a contact ring f whilst the other
terminal a¹ of the branch or consumers circuit is connected to a second contact
ring g.
In order to close the circuit a plug h is inserted into these rings. The plug is
made in two pieces j k of non conducting material fitting one within the other
and carrying respectively a conducting plug j¹ and band k. These fit the contact
rings fg and are connected by a fuse wire which lies within the outer part j
of the plug. The parts jk are fixed together by a screw m.
The positive conductor which is usually the inner conductor in a triple cable
can be similarly connected to the circuit through one of the conducting rings.
This arrangement is shown in plan at Figure 4 where n is the attachment for
connecting the positive conductor to the ring f. In this case the bridge piece d
connecting the bared ends of the negative conductor a is not connected to the
circuit; in other respects the arrangement is similar to that shown at Figures 1
to 3.
Having now particularly described and ascertained the nature of our said in-
vention and in what manner the same is to be performed we declare that what
we claim is:-
1. The combination with a service box of a plug switch substantially as de-
scribed.
2. The combined plug switch and fuse substantially as described and illustrated
in the drawings.
3. Apparatus for connecting branch circuits to electric mains substantially as
described and illustrated in the drawings.
Dated this 5th day of March 1900.
CALLENDERS CABLE & CONSTRUCTION COMPANY, LIMITED,
HENRY DRAKE,
T. O. CALLENDER,
H. L. MANNING,
Directors.
Secy.
T. O. CALLENDER.