Hello:

I'm going to replace those two items, but do I need to turn the power off at the box before I mess with 'em?

excon

It would be wise to... if you don't have a Multimeter or something to confirm you cut power at the right breaker(s) by checking at the appliences... if you don't... its safer to cut it to everything.

Hello again, smoothy:

What could happen if I don't? Could I be careful and not get myself killed?

excon

You could do it... the risk is hitting a live wire with one hand... while you ground yourself with the other hand... and get a path of curent across your upper chest and heart which COULD stop your heart...

Wear dry gloves... take wires off one at a time.. and put a wire nut on them and you might be OK... I could do it.. the average electrician could do it... but I've got to still say its not safe... I've gotten zapped a few times over the years even with precautions when I couldn't kill the power because I had to have it on at the time for other reasons.

If you aren't comfortable working with 120vac... I'd honestly recommend you rethink killing the power long enough to unhook and cap the wires. Its only a few minutes for you to unhook them to cap them with wire nuts or electrical tape then turn the power back on until you are ready to hook up the new appliances.

Hello again, smoothy;

Thanks. That's what I'll do.

excon

Always turn off all power servicing all appliances that operates all devices within any electrical circuit that is attached to the unit in question. In other terms turn the power off to as many circuits as possible without hindering the power necessary to test the device when necessary.