A plumber is tasked with replacing an older electric hot water heater (150 L capacity) with a new, more efficient model of the same capacity in a detached residential home. The existing electrical service is 100 amps. The new water heater requires a dedicated 30 amp, 240 V circuit. How should the plumber confirm the existing electrical infrastructure can support this installation?

Question: A plumber is tasked with replacing an older electric hot water heater (150 L capacity) with a new, more efficient model of the same capacity in a detached residential home. The existing electrical service is 100 amps. The new water heater requires a dedicated 30 amp, 240 V circuit. How should the plumber confirm the existing electrical infrastructure can support this installation?

Answer options: ✅ Verify the main electrical panel has an available 2-pole breaker space and confirm wire gauge for existing or new circuit.

• Assume the 100-amp service is sufficient for a single new appliance.
• Check only the existing wiring leading to the old hot water heater for suitability.
• Consult with the homeowner to see if they have other large appliances planned.

Correct answer: Verify the main electrical panel has an available 2-pole breaker space and confirm wire gauge for existing or new circuit.

Explanation: The plumber must verify that the main electrical panel has an available space for a new 2-pole 30 A breaker and that the conductors are adequately sized for the new appliance's load, as per the Canadian Electrical Code (CSA C22.1). Simply assuming sufficiency or only checking existing wiring is inadequate. While other appliances can affect overall load, the immediate concern is the dedicated circuit for the water heater.