Thought I'd add my two cents....
I have to keep certain toning chemistry at 120* for up to 40 minutes at a
time. I use hot water in a second tray under the toner with very little
problem, but I have recently found that covering the toner with glass helps
enormously. It also has cut back on the loss of toner through evaporation
(not to mention breathing fumes!).
Further, I have found that covering the tray can actually *raise* the toner
temp when it starts to slip....
Re: all the aformentioned electrical devices....I personally would want the
ground-fault protection - especially if your wiring isn't recent (ie fuses).
I'm not sure if it's a straight replacement of the standard outlet (and
therefore do-able by the handy - you'd obviously need an active ground wire
throughout the system), but it seems worth the small expense to have an
electrician do the job if it's not. House current is plenty potent enough
to bring a sudden conclusion to all our little projects.
Good luck!
Jon Bailey