Hi @Salman_89,
Welcome to AGL Neighbourhood!
To connect hot water system to Controlled Load meter, you would need to contact an electrician. If they have advised you that they can't connect a second hot water system to the same Controlled Load register, then you may need to get your meter altered to allow you to do this.
This is something that you would need to have a chat to our New Connections team about. They're available on 1800 680 430, Monday to Friday 8am to 5.30pm (AEST).
Kind Regards,
-Olgi-