The 30 Amp breaker should be okay for the 5500W water heater. The Rheem Performance Plus 50 gallon water heater, XE50M09EL55U1, requires a 30A breaker for 208V and 240V electrical systems (single or 3 phase wiring). See pages 8-9 of the manual: https://images.homedepot-static.com/catalog/pdfimages/e2/e20f6bed-6a61-43a8-b7d9-d9dd2dae94e1.pdf .
You should check the installation manual for your new water heater, just in case. I hope this helps.
Answers & Comments
The 30 Amp breaker should be okay for the 5500W water heater. The Rheem Performance Plus 50 gallon water heater, XE50M09EL55U1, requires a 30A breaker for 208V and 240V electrical systems (single or 3 phase wiring). See pages 8-9 of the manual: https://images.homedepot-static.com/catalog/pdfimages/e2/e20f6bed-6a61-43a8-b7d9-d9dd2dae94e1.pdf .
You should check the installation manual for your new water heater, just in case. I hope this helps.
Cindy Wells