Brief question for the sparks here.. I've never seen a meter installed on its side, but just because something isnt done usually, doesnt mean it can't!
I'd like to reposition my meter and it would be great if I could also take the wooden panel that the meter and the service header are mounted on and rotate them 90 degrees. The meters I've taken apart before have been largely mechanical and havent obviously had any components that are kept in place by gravity and hence requires them to be oriented normally
Many Many years ago I found a meter board mounted on hinges and I inquired as to why. It seems the meter had been removed from the wall to decorate and it was noticed the meter had stopped so once completed he had added hinges so he could drop the board for a few weeks after being read to reduce the bill.
After that I did have to remove a few boards on temporary basis and I checked to see if same happened and only once did it slow down but I would think that the board would have instructed their guys they must be upright.
Most likely it would not affect the reading but it could do and in either direction.
So I would think the answer would be no.
But I know of no regulation to stop you but I have never looked for one.
You are not allowed to touch your electric meter as it is the property of the electricity supplier , also the board its mounted on is their property. By attempting to move the meter yourself you are not only breaking the law by tampering with their equipment , but you could potentially kill yourself if you are not sure what you are doing. In 18 Years as a sparks i have never seen a meter mounted sideways. If you need it moving then seek advice from your electricity supplier.