What are the aluminum joist plates included with the system?

Small aluminum joist plates are included to protect the joists where the Hott-Wire cable crosses over them during installation. Because Hott-Wire is a line-voltage cable, direct contact with the wood joist at crossing points needs to be avoided — the joist plates sit between the cable and the joist surface at those points, protecting the wood and maintaining a safe installation. They are part of the complete system package.