General Wiring and Assembly

Owned by Jack Christensen
Last updated: Apr 18, 2022
2 min read

  • Any electrical system that may be unsafe to approach while powered should have a manual kill switch installed that: 

    • Disables all energetics or potentially unsafe components.

    • Can be operated without requiring the rocket to be taken off the tower (e.g. mag-switches).

    • Does not require any software to work.

  • All mission critical components should have a hot-swappable replacement. You should have that replacement’s location written down. ”Hot-swappable” means you can replace it without any powered tools.

  • Buy spares for all components provided it is not prohibitively expensive.

  • Wiring should be done so that the circuit is as readable as possible. If supplies allow, use a different insulation color for each wire. At the very least, positive should be red, ground should be black, and all other wires should not be red or black. 

  • If there is space, and it is likely wires could get easily mixed up, wires should be labeled.

  • All switches and connectors need unambiguous labeling. Labeling should be permanent (i.e. not on tape, etc).

  • All wires used should be rated for the current going through them.

  • Strain relief:

    • Wires that get handled, moved, or torqued at any point should be strain relieved on both sides of that point.

    • Wires should be relieved to the point where they can survive very violent shaking (especially if the system will be going in the rocket).

    • Avoid tight wires between two points. 

  • RC lithium polymer batteries should be fused as they can sink up to 50 A. 

  • When designing a box, circuit layout, or other assembly, keep in mind that wires and electrical components do take up space. Leave clearance in the design stage; this problem should be solved before fabrication/assembly.

  • If possible, put hot-swappable components such as batteries or modular PCBs in locations where they are easily accessible.

  • Use standoffs to make sure the circuit board has good isolation from what’s beneath it. This is especially important if the board is mounted on a metal plate. 

  • When using shielded cable, ensure the shield is properly terminated and grounded.

  • If it’s conceivably possible for a component to be installed backwards, there should be idiot proof documentation of which way it goes, that documentation should be less than 2 inches from the install point.