.. keeping in mind, of course, that the label on the CB may not indicate ALL the services which take power from that circuit ie you don't necessarily KNOW what may have a problem ... you just might give yourself an unwanted surprise by playing with the panel.
Wise words form J-T
G00gle National Airlines DC10 Flight 27,back in 1973, and look particularly for the CVR transcript. There you should find a discussion between the Capt. and the Flight Engineer and the pulling of an N1 Tachometer CB, and the consequences.