EMT and grounding

I am going to be wiring a circuit of lights and plugs for a pumphouse/Shed. I am planning to use metal boxes and flexible steel conduit. This will be a simple 20-amp circuit with a couple of outlets and a couple of switched lights. I see pre-wired flexible steel conduit at the Home centers and this seems like just the ticket for me. But if I may ask a really stupid question, how does one safely and cleanly cut the conduit to desired lengths without cutting or nicking the wires? Is there a special tool for this? Thanks in advance, Kevin

After a recent hard rain I woke to water in my fuse box! No kidding. There was about 8oz. of water that had puddled on the bottom of the box and the shelf right below it. After absorbing the water carefully with a rag, I started to carefully poke around. I found no water on any of the wires---including the main power and ground line. I pulled the board off of the block wall that the fuse box is mounted to and found nothing. I then went outside and looked at the main line to the house. The meter/main line is on the same wall as the fuse box. I noticed that my main power wire is not in conduit. It's protected, but not in conduit. It runs from the roof down to the meter and then on down about 2' and into a small box about 3" square which goes into the siding and further into the house. I noticed some gaps around this 3" box. I cleaned it real good and then calked it. Thinking I solved the problem, I put a fan next to the electrical box and walked away figuring I had solved it. We had another hard rain today and it happened again! I went back and looked above the fuse box at the wires and saw nothing---no water anywhere---I even used a dentist mirror and 30min. of my time looking. Nothing. Went back outside and noticed on the bottom of the 3" box that I caulked I had missed a spot. I cleaned it and caulked it shut. I then put a plastic bag over it with duct tape to seal out moisture while the caulk dried. I called the electric company and they came out and looked. They said that what I was experiencing was somewhat normal!! What? He said I did the right thing by caulking and that I might consider a "cap" on the wire/meter outside. My wife talked to the guy since I was in the car coming home from work. I know this is a long shot---any idea what they heck he is talking about when he mentions this "cap?" I don't feel comfortable with ANY water in my electrical box. I know the foundation isn't leaking as there is no water coming from any of the walls. There isn't any water anywhere in my basement other than in the bottom of the fuse box. Ideas? Thanks, Curt B. Shumaker