Within 90 days after installation or exchange of any meter with associated instrument transformers and/or phase-shifting transformers, a post-installation inspection shall be made under load to determine if the meter is accurately measuring customer energy consumption. At a new or re-wired metering location, where the installation includes potential transformers, the inspection shall be performed by someone other than the original installer.
Ill. Admin. Code tit. 83, § 410.155