An electrical CAD drawings package covers everything from the high-level distribution architecture to the individual circuit details needed for installation and commissioning. Understanding what a full package includes helps engineers, contractors, and project managers specify and review electrical drawing deliverables correctly.
Single line diagrams
The single line diagram (SLD) is the primary document showing the electrical distribution architecture. It represents a three-phase system as a single line, showing the main incoming supply, switchgear, transformers, distribution boards, and major loads in a simplified schematic form. SLDs are used for system design, protection coordination, and fault level analysis.
Schematic drawings
Electrical schematics show the detailed control and power circuit wiring for specific systems or equipment. Unlike SLDs which show the overall distribution architecture, schematics show the individual components and their wiring connections in full detail. Motor control circuits, protection relay schemes, and PLC input/output wiring are all represented in schematic form.
Panel layout drawings
Panel layout drawings show the physical arrangement of components inside electrical panels, distribution boards, and motor control centres. They include the positions of circuit breakers, contactors, relays, terminals, cable entry points, and labelling. Panel layout drawings are used for panel manufacture, installation, and maintenance.
Wiring diagrams
Wiring diagrams show point-to-point connections between individual terminals, cables, and components. They are the most detailed level of electrical documentation, used for cable installation, termination, and fault-finding. Modern wiring diagrams are typically produced from a database rather than drawn manually, with each terminal and cable reference tracked systematically.
Cable schedules
Cable schedules list every cable in a system: cable number, type, size, route, origin, destination, and termination details. They are used for cable procurement, installation, and testing. Cable schedules are often produced alongside the wiring diagrams from the same underlying data.
Fire alarm and emergency systems drawings
Fire alarm systems require their own dedicated drawing set, typically including a zone plan showing detector and call point locations on a floor plan, a schematic showing the panel connections, and a cable schedule. Emergency lighting systems similarly require layout drawings showing luminaire positions and circuit routing.
Earthing and lightning protection drawings
Earthing drawings show the earthing electrode arrangement, main earthing connections, and equipotential bonding routes. Lightning protection drawings show the air termination network, down conductor routes, and earth termination arrangement. Both are required for installations where BS EN 62305 and BS 7430 compliance needs to be demonstrated.
Outsource CAD
Outsource CAD produces complete electrical CAD drawing packages for commercial, industrial, and infrastructure projects across the UK. All drawings are produced in AutoCAD to BS 7671 conventions. Contact info@outsourcecad.com or call +44 28 9009 8876.
