Since I moved in to my house just over a year ago I have had 2 electricity meters. One changes as I use electricity, the other just stays at the same reading. The meter that moves has DOM written above for domestic probably. The other one has O/P written above it. What does O/P mean? I have trouble given meter readings as they always estimate that the meter must be in use. I have also been trying to get meters changed but have a shared fuse, but that's another problem. Just the now wondering what O/P could mean.