The e18S and e18S-3 have an amperage draw of 23.9 amps. It is possible to supply this with a 30 amp plug. This would be a 6 foot cord and the various plug options that are available are available for this kiln. NEMA 14-30 or NEMA 14-50 would not have an upcharge.
These 30 amp cords will also work on JD18 and JD18-3 kilns.
This does not affect the c-MET-us listing.