Engineering and Technical Support Group
School of Information Technology & Electrical Engineering

Design Rules > Routing

Protel 99 Path = Design > Rules > Routing

> Clearance Constraint

= 10mil : All Objects

> Routing Via Style

= 50mil dia / 20mil hole  :  Preferred Size

= 50mil dia / 20mil hole :  Minimum Size

> Width Constraint

= minimum 10mil

= preferred 12mil

= maximum user defined

NB: Wider tracks are mechanically superior.  Choose carefully!

Design Rules > Manufacturing

Protel 99 Path = Design > Rules > Manufacturing

> Hole Size Constraint

= minimum 20mil  :  Define hole sizes in 4mil increments

= maximum user defined :  starting at 20mil (0.5mm)

> Minimum Annular Ring

= minimum 10mil  EXTREMELY IMPORTANT!

> Polygon Connect Style

= Rule Attributes

= Conductor Width

= Conductors

= Angle         

= Filter Kind    

= Pwr Plane Clearance

Relief Connect



90 Angle

Whole Board


: Nominal

: Nominal

: Nominal

: Nominal

: Nominal

: Nominal

Design Options > Options

Protel 99 Path = Design > Options > Options

> Grids

= Snap X

= Snap Y

= Component X

= Component Y





: Nominal

: Nominal

: Nominal

: Nominal

> Measurement Unit

= Imperial


: Preferred

Position in Workspace

Place the PCB design such that the lower left corner of the PCB is at workspace coordinate 1000mil, 1000mil.


  • Ensure borders are created on ALL electrical layers using 10mil tracks.  We require these borders to assist in artwork alignment (Tip - try using multilayer for borders).
  • It is recommended that there is a minimum clearance of 120mil (3mm) between the edge of the board and all PCB elements.

Mounting Requirements

  • Do you need mounting holes
  • For M3 mounting holes use PCB library component SPACER01 in KBpcb05 library

Final Checks

Ensure you check your schematic running ERC, and PCB by running DRC

Manufacturing Options

  • We do not produce etched PCB's with plated through holes.  You must therefore ensure all pads and vias that require soldering are accessible and not obstructed in any way.
  • If you do require plated through holes we can manufacture your PCB in the Electronics Engineering Laboratory using alternative technology.


It is important to note that a large number of PCB footprints intended for through hole components supplied by Protel are incompatible with our manufacturing process.

It is therefore recommended that you use the Electronics Engineering Laboratory Libraries which support many of the components held by this facility and are fully compatible with our PCB manufacturing process.

Schematic and PCB libraries are available for download from the Engineering & Technical Support Group website.

If you have already designed your PCB using (TH) footprints supplied by Protel, it is suggested that you carry out a thorough inspection with respect to physical size, annular ring and hole size requirements for each component before submitting your design for manufacture.

Library Catalogue Access

The Protel Library Catalogue displays the contents of our Schematic and PCB Libraries and is accessible at the following locations:

  1. Electronics Engineering Lab student computing area  >  Non-removable hard copy
  2. Engineering & Technical Support Group website  >  PDF files for download


Please email any suggestions to the Engineering & Technical Support Group Manager