The Electrical System gallery offers 159 illustrations of household wiring, switches, and other electrical elements. For electrical lighting, please see the Electric Lighting gallery.

"Edison fuse plug cutout for switchboard use." —Croft 1920

Edison Fuse Plug Cut-Out

"Edison fuse plug cutout for switchboard use." —Croft 1920

A safety device that protects an electric circuit from becoming overloaded. Fuses contain a length of thin wire (usually of a metal alloy) that melts and breaks the circuit if too much current flows through it. They were traditionally used to protect electronic equipment and prevent fires, but have largely been replaced by circuit breakers.

Electric Fuse

A safety device that protects an electric circuit from becoming overloaded. Fuses contain a length of…

A cupped-disc-gap protector.

Gap Protector

A cupped-disc-gap protector.

A Garton-Daniels lightning protector.

Garton-Daniels

A Garton-Daniels lightning protector.

Loss in a suction gas-producer plant.

Gas-producer Plant

Loss in a suction gas-producer plant.

A direct-connected generating unit. A high-speed piston-valve engine driving a small alternator.

Generating Unit

A direct-connected generating unit. A high-speed piston-valve engine driving a small alternator.

Graphic record produced by General Electric Company's Type G demand meter.

Graphic Record

Graphic record produced by General Electric Company's Type G demand meter.

Lamp ground detectors for two and three-wire circuits.

ground detectors

Lamp ground detectors for two and three-wire circuits.

A ground wire over a three-phase transmission circuit.

Ground Wire

A ground wire over a three-phase transmission circuit.

Different views of a grounded metallic comb to relieve belt of static charge

Grounded metallic comb

Different views of a grounded metallic comb to relieve belt of static charge

A graphic definition of the term "head".

Head

A graphic definition of the term "head".

Boring holes around a bridge.

Hole

Boring holes around a bridge.

A horn-gap protector for air conditioner series lightning circuits.

Horn-gap Protector

A horn-gap protector for air conditioner series lightning circuits.

Illustrating the nomenclature of the essential elements of a hydro-electric development.

Hydro-electric Development

Illustrating the nomenclature of the essential elements of a hydro-electric development.

Sectional elevation of a typical 110,000 volt hydro-electric generating station.

Hydro-electric Station

Sectional elevation of a typical 110,000 volt hydro-electric generating station.

Impulse wheel and nozzle.

Impulse Wheel

Impulse wheel and nozzle.

Determination of an average load imposed by an industrial plant.

Industrial Plant

Determination of an average load imposed by an industrial plant.

End elevation of the control desk and instrument board.

Instrument Board

End elevation of the control desk and instrument board.

Instrument post used instead of a panel switchboard.

Instrument Post

Instrument post used instead of a panel switchboard.

A General Electric "hour glass" choke coil insulated for 35,000 volts.

Insulated Choke Coil

A General Electric "hour glass" choke coil insulated for 35,000 volts.

Motor insulated on a parallel timber base.

Insulated motor

Motor insulated on a parallel timber base.

Illustrating method of measuring insulation resistance

insulation

Illustrating method of measuring insulation resistance

Testing the insulation resistance of an armature.

insulation resistance

Testing the insulation resistance of an armature.

A two pole front connected knife switch fused at the handle end.

knife switch

A two pole front connected knife switch fused at the handle end.

A three pole rear connected knife switch fused on the hinge end.

knife switch

A three pole rear connected knife switch fused on the hinge end.

Showing the construction of a quick break knife switch.

knife switch

Showing the construction of a quick break knife switch.

Knopp test set for determining current in direct-current conductors.

Knopp Test

Knopp test set for determining current in direct-current conductors.

Installation of Kuhlo wire in a residence.

Kuhlo Wire

Installation of Kuhlo wire in a residence.

A box with a lamp inside to demonstrate a galvanometer.

Lamp Box

A box with a lamp inside to demonstrate a galvanometer.

Incandescent lamps for exploring.

Lamps

Incandescent lamps for exploring.

Showing leakage current through the frame of a machine which is insulated from ground.

leakage current

Showing leakage current through the frame of a machine which is insulated from ground.

Fixtures used in a Boston house wiring campaign.  (Listed at consumer price).  Fixtures sold in finished-building wiring campaign by the Union Electric Light & Power Company of St. Louis, Missouri.

Light Fixtures

Fixtures used in a Boston house wiring campaign. (Listed at consumer price). Fixtures sold in finished-building…

Illustrating the principle of the magnetic blow-out lightning protector.

Lightning Protector

Illustrating the principle of the magnetic blow-out lightning protector.

A Pierce line wire, horn-gap protector.

Line Wire

A Pierce line wire, horn-gap protector.

A magnetic locator.

Magnetic Locator

A magnetic locator.

Installation of metal molding to serve brackets.

Metal Molding

Installation of metal molding to serve brackets.

Testing the insulation resistance of a motor or generator from its winding to ground.

Motor

Testing the insulation resistance of a motor or generator from its winding to ground.

Alternating-current motor installation.

motor

Alternating-current motor installation.

A method of mounting a box for a bracket fixture.

Mounting Box

A method of mounting a box for a bracket fixture.

A multigap protector mounted on a pole for transformer protection.

Multigap Protector

A multigap protector mounted on a pole for transformer protection.

A multipath protector in a wooden box for outdoor installation.

Multipath Protector

A multipath protector in a wooden box for outdoor installation.

Section through a small, low pressure oil engine of the "hot-bulb" or "hot-ball" type.

Oil Engine

Section through a small, low pressure oil engine of the "hot-bulb" or "hot-ball" type.

Remote control oil switch in masonry-cell mounting.

Oil Switch

Remote control oil switch in masonry-cell mounting.

The circulating oil-type transformer.

Oil-type Transformer

The circulating oil-type transformer.

Supporting outlet box on a furred ceiling.

Outlet Box

Supporting outlet box on a furred ceiling.

A panel box in a rigid conduit installation.

Panel Box

A panel box in a rigid conduit installation.

Examining a partition interior.

Partition

Examining a partition interior.

Finding the average load from a load graph with a planimeter

Planimeter

Finding the average load from a load graph with a planimeter

An Amsler-type polar planimeter that is being used to measure the area of a load graph.

Polar Planimeter

An Amsler-type polar planimeter that is being used to measure the area of a load graph.

An illustration showing the distribution losses in a small, alternating current central station.

Power Lines

An illustration showing the distribution losses in a small, alternating current central station.

A printometer-type demand meter arranged in a self-contained case for field tests.

Printometer

A printometer-type demand meter arranged in a self-contained case for field tests.

Schematic connection diagram for a grounded-neutral, three-phase electrolytic protector.

Protector

Schematic connection diagram for a grounded-neutral, three-phase electrolytic protector.

Outdoor-type, cupped-disc-gap protectors on a three-phase line.

Protectors

Outdoor-type, cupped-disc-gap protectors on a three-phase line.

Grounded street railway circuit.

railway circuit

Grounded street railway circuit.

Ratchet drills.

Ratchet Drills

Ratchet drills.

A current-limiting reactor.

Reactor

A current-limiting reactor.

Rear elevation of the switchboard with the perspective and front views.

Rear Elevation of Switchboard

Rear elevation of the switchboard with the perspective and front views.

A regulator for small, direct-current generators.

Regulator

A regulator for small, direct-current generators.

Rigid conduit inserted where the conduit is exposed to moisture.

Rigid Conduit

Rigid conduit inserted where the conduit is exposed to moisture.

A device when vibrates causes bells to ring.bell, acoustic device, signaling device

Device Ringer

A device when vibrates causes bells to ring.bell, acoustic device, signaling device