Smoke from the fusebox switch but everything seems be working
Some termonolog may be in order, your service panel or breaker panel is where you installed an arc fault device? Don't know of any fuse box versions. Did you have the breaker turned off when you snapped it in? A load on a breaker when inserted can cause an arc flash with smoke and maybe minor damage to the buss or breaker. Since things now work it may be fine but I would want to inspect the buss and contacts on the breaker if all looks good it may have been a minor arc that did not cause harm that would make it unsafe.