IIRC a few - Gurnee and Zion come to mind (poss. also Northbrook and Des Plaines).
As an example - Highland Park:
Quote
Article 90 - Introduction (1) Section 90-8 (c) shall be added to read as follows: 172-1 90-8. (c) - Wiring Planning. In new construction, for future expansion, a minimum of ten percent (10%) of the available spaces in a panel shall be provided as spares or blank.
