Year: 1887

page_text: Date of Application, 10th May, 1887
Complete Left, 12th Nov., 1887
Complete Accepted; 13th Dec., 1887
I ROBERT WILLIAM EDDISON of Steam Plough Works Leeds in the County of
York Engineer do hereby declare the nature of the said Invention which has been
communicated to me from abroad from Tatham & Brothers of Philadelphia in the
State of Pennsylvania United States of America Lead Manufacturers and David
Brooks of Philadelphia aforesaid Electrician to be as follows :-
This Invention relates to electrical insulated conductors lines or cables enclosed in
a metal tube or casing and the said Invention has for its object to obviate liability of
loss by short circuiting or leakage of the current through the said metal tube or
casing to earth as it has been found in practice that the insulating material usually
used to envelope the conducting wires when exposed to the atmosphere has a tendency
to absorb or become coated with moisture so that at the terminations of lines or cables
at which the insulation and conductors are exposed to make connections this moisture
is liable to make electrical contact between the conductors and the metal tube or
casing of the line or cable and so allow the current to pass from the conductors
through the metal tube or casing to earth.
According to this Invention the metallic continuity of the metal tube or casing is
broken or formed with a gap therein so as to destroy the circuit for the escape of
current which otherwise exists through the metal tube or casing. This may be
effected in various ways but the gap or breaking of the metallic continuity of the
metal tube or casing occurs between the exposed end of the line on the one side and
the first place at which there is contact between the metal tube or casing and earth.
I may fill in the gap with insulating material or I may bridge it over with a tube or
sleeve of India rubber or other insulating material (steeped or not in paraffin or the
The
like) or with a tube of metal insulated from the main metal tube or casing.
insulating sleeve may be tightly lashed or secured to the metal tube or casing on
either side of the gap.
If therefore any moisture should make electric contact between the end of the
metal tube or casing and the conductors the current cannot pass to the main part of
the said metal tube or casing by reason of the gap and insulation as described.
Doted this 10th day of May 1887
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C.,
Agents.

page_text: COMPLETE SPECIFICATION.
Improvements in Metal Cased Electric Lines or Cables.
I ROBERT WILLIAM EDDISON of Steam Plough Works Leeds in the County of
York Engineer do hereby declare the nature of the said Invention which has been
communicated to me from abroad by Tatham and Brothers of Philadelphia in the State
of Pennsylvania United States of America Lead Manufacturers and David Brooks
of Philadelphia aforesaid Electrician and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:
This Invention relates to electrical insulated conductors lines or cables enclosed
in a metal tube or casing and the said invention has for its object to obviate liability
of loss by short circuiting or leakage of the current through the said metal tube or
casing to earth as it has been found in practice that the insulating material usually
used to envelope the conducting wires when exposed to the atmosphere has a tendency
to absorb or become coated with moisture so that at the terminations of lines or cables
at which the insulation and conductors are exposed (to make connections with lamps
or the like for example) this moisture is liable to make electrical contact between the
conductors and the metal tube or casing of the line or cable and so allow the current
to pass from the conductors through the metal tube or casing to earth.
According to this Invention the metallic continuity of the metal tube or casing is
disconnected broken or formed with a gap therein of such an extent as to destroy the
circuit for the escape of current which otherwise exists through the metal tube or
casing. This may be effected in various ways but the gap or breaking of the metallic
continuity of the metal tube or casing occurs between the exposed end of the line
on the one side and the first place at which there is contact between the metal tube or
casing and earth. The gap may be filled in with insulating and moisture resisting
material or it may be bridged over with a tube or sleeve of india rubber or other
insulating and moisture resisting material (for example indiarubber steeped in paraffin
or the like) or both methods combined may be used. The insulating sleeve may
be tightly lashed or secured to the metal tube or casing on either side of the gap.
If therefore any moisture should make eléctric contact between the end of the metal
tube or casing and the conductors the current cannot pass to the main part of the
said metal tube or casing by reason of the gap and insulation as described.
And in order that my said invention may be fully understood I shall now proceed
more particularly to describe the same and for that purpose shall refer to the several
figures on the annexed sheet of drawings the same letters of reference indicating
corresponding parts in all the figures.
In the accompanying drawings Figure 1 is a view of the terminal end of a metal
encased insulated electrical conductor. Figures 2 and 3 are views illustrating the
manner according to this invention of insulating the terminal so as to prevent leakage
to the earth from the conductor through the metal sheathing and Figure 4 is a
transverse section on the line 1-2 Figure 3.

page_text: In Figure 1, A is the electrical conductor with a fibrous or other insulating cover B
enclosed in a lead or other metal sheathing or pipe D.
In carrying out this Invention the outer metal sheathing is first severed at some
little distance from the end say a foot and cut away for a suitable length as shewn
at a Figuro 2. It is preferred also to cut away the fibrous insulating material for
about the same length. There is then slipped over the disconnected end'and extending onto
the end of the main part of the sheathing a sleeve E of rubber or other suitable material
Figure 3 which will resist moisture and at the same time be an electrical insulator.
For greater security the sleeve is bound down at ee on to the metal sheathing to
prevent moisture from creeping underneath. By this means the collection of moisture on
the insulating material B at the end of the pipe making a more or less imperfect
electrical connection between the wire and the severed or disconnected end of the pipe
will not be of any importance and will not cause any leakage to the earth since the
severed end of the pipe is disconnected from the ground by the insulating and
moisture resisting body E.
Having now particularly described and ascertained the nature of the said Invention
and in what manner the same is to be performed I declare that what I claim is.—
1st. The combination of the terminal of an insulated electrical conductor with a
metal sheathing having its end disconnected from its main part and a moisture
resisting and insulating substance interposed between the said disconnected end and
main part of the sheathing substantially as set forth.
2nd. The combination of the terminal of an insulated electrical conductor with a
metal sheathing having its end disconnected from its main part and a rubber sleeve
connecting the two parts of the sheathing substantially as set forth.
Dated the 19th f NL 1007
J. H. JOHNSON & Co.,
Agents.