Need a deeper metal switchbox
Hello, help please. How can I add depth to a metal cut-in switchbox in a lath/plaster wall? I have added a bathroom heater/fan/light, with multi-function switch. I used a metal box with 14-2 w/ground MC cable. This switch requires 11 wires coming into the box in addition to a few pigtails on the switch, and all that doesn't fit into the 2-1/2" deep switchbox. Someone suggested I use a "battleship" (aka "box support"?), so I purchased one for about a buck, but I can't figure out how to use it. It's actually a 2-Gang box because I'm putting another switch in it, as well. Any tips on another approach or how to use a battleship would be appreciated.