Do you mean jumping the meter socket or just clipping service drop at the weatherhead? We've been temping with split bolts directly to the new service risers allowing about 2 ft of slop length for POCO to complete. As far as actual operation, it depends on situation. Is the weatherhead easily accessible from ladder? Is the new riser close to point of attachment? We usually just clip service, drop old risers and socket, install new socket, risers, entry, panel and then split bolt to drop for temp, call for inspection and AHJ clears job for POCO. This way usually insures only one "amish day" for the building. If you haven't clipped a service before, try to get someone who has; or be ever mindful of: integrity of point-of-attachment, any stress on conductors which may be relieved by cutting(and create motion of conductors), insulation and safety of YOURSELF. From your post, it seems that drop is a single phase(one conductor) as far as loading that until 220 is supplied, do you mean to connect both new risers to the one conductor on the existing drop? And all of the above applies to overhead service, is that so in this case?
