BD
Plug-in busway
Busway with tap-off outlets along its length, drawn with outlet marks where plug-in units can be connected.
SLD / GA
Symbols · TO
Busway tap-off connection
The connection of an outgoing circuit to a plug-in busway through a tap-off unit, usually containing a protective device.
In plain English
What does Busway tap-off connection mean?
This symbol shows a tap-off unit plugged into the busway, with the outgoing circuit leaving through a fuse or circuit breaker in the unit. On single-line diagrams it replaces the board-and-feeder pattern used for switchboards, since the busway itself acts as the distribution bus.
A simple example
The connection symbol does not show the tap-off unit rating unless annotated. Tap-off units may be fused or contain a breaker, and they usually have an interlock preventing insertion or removal under load. The protective device inside the unit should be drawn with its own symbol and rating.
What the drawings help you do
Read the protective device rating in the tap-off unit. Check selectivity between the tap-off device and busway upstream protection. A busway tap-off is a plug-in connection with its own protection; a one-line bus tap is a generic connection to a busbar.
This particular reference
The connection of an outgoing circuit to a plug-in busway through a tap-off unit, usually containing a protective device. A busway tap-off is a plug-in connection with its own protection; a one-line bus tap is a generic connection to a busbar.
- Terminal
- An identified point where a conductor connects.
- Rating
- A value stating the conditions for which equipment is specified.
- Schematic
- A drawing showing function and connections rather than physical appearance.
Read the source: Canalis busbar trunking systems · Autodesk IEC-60617 preview: One-line bus-tap representation
SLD · TO
What it represents
This symbol shows a tap-off unit plugged into the busway, with the outgoing circuit leaving through a fuse or circuit breaker in the unit. On single-line diagrams it replaces the board-and-feeder pattern used for switchboards, since the busway itself acts as the distribution bus.
The connection symbol does not show the tap-off unit rating unless annotated. Tap-off units may be fused or contain a breaker, and they usually have an interlock preventing insertion or removal under load. The protective device inside the unit should be drawn with its own symbol and rating.
How to read it
- Read the protective device rating in the tap-off unit.
- Check selectivity between the tap-off device and busway upstream protection.
Information to show or reference
- Draw the protective device in the tap-off.
- State tap-off rating.
- Identify the busway outlet position.
A distinction that matters
A busway tap-off is a plug-in connection with its own protection; a one-line bus tap is a generic connection to a busbar.
Sources you can follow
These public references support the explanation and provide further detail. Their graphics and downloadable files remain with their publishers.
Canalis busbar trunking systems
Manufacturer busbar trunking ranges with tap-off units.
Autodesk IEC-60617 preview: One-line bus-tap representation
Public IEC-oriented one-line bus-tap representation for comparison.
About this graphic
This illustration was authored independently by Elora Grid to explain the concept. It is not reproduced from a customer drawing, an official standard graphic or a manufacturer CAD file. Its correspondence to an exact IEC or IEEE symbol identifier has not been certified.
SVG and DXF downloads contain this original artwork. DXF uses unscaled drawing units; a GA envelope supplies no product dimensions, clearances or fabrication information. Original artwork is available under CC BY 4.0. Third-party references retain their own terms.
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