Non-ferrous chassis and fire safety

[KT]

Hello,

I've seen some cool chassis recently made out of wood and some out of plastic. I myself, just recently built a SN Dackit inside a Sterilite container (like Tupperware). It was easy to build and looks kinda cool. Works great so far with an outboard SLA.

In keeping in line with the Tupperware theme, I started building a little chassis for my SN TubeDac+. As I finished drilling holes in the PS box, I realized that I was putting a 12V 100VA transformer inside a plastic box. The 120V AC is coming in via a standard IEC socket and the PS is fused on the primary side and has an on/off switch that breaks both the hot and ground connections, but I got a little worried about the safety of this, particularly regarding fire.

I know Scott Nixon sells a PS for the TubeDac that's built in a ABS plastic box (I didn't see a fuse or on/off switch in the pictures). This is also essentially just a transformer in a case. He also builds the TubeDac+ in a similar ABS plastic box. I assume that he's thought this out and figured it was OK.

Also, some commercially available amps with little dissipation, like the Sonic Impact amps, are built in little plastic boxes, as are alarm clocks and tabletop transistor radios.

More powerful amps, like the DNM acrylic cased amps, also use plastic.

Are there any specific concerns I should be mindful of, or am I safe as long as I ground and fuse everything appropriately. What's the safety code for using wood and plastic as a chassis?

I'd love to hear your thought on this.

Thanks,
KT