total noob question, mic and guitar

Hi, I’ve been in the process of putting together a little home studio for me and my mates to muck around and have some fun with. I play guitar with amplitube and am delighted by the results from the c1 over my old 16 bit peavey xport. I have it set up in reaper with no problems, just using an 25 key midi keyboard and control surface.

The next purchase needs to be a mic, and I would like a condenser, which obviously needs the phantom power. My question is, if the guitar is connected on line 1 Hi-z and i phantom power a mic through line 2, am I going to be knocking 48 volts into my guitar?

The idea we have is that i can use the mic for vocals. So, guitar and phantom power, is this a viable proposition? Or would I be better buying a USB condenser and a dynamic for vocals? I’m such a noob to all this, but so far the c1 has been fantastic.

thinking about it the answer probably is a dynamic and a usb, so i can skype ideas through to others through usb on my laptop whilst using my desktop with the c1, but for reference sake, the question is still there. I understand the XLR will be hitting different pins in the inplug compared to the unbalanced guitar cable, so is it safe to assume that with phantom power on, line 1 will still behave as a hi-z input, and not be sending 48 volts back into my guitar pots?