Hot Topics: Wondering How to Wire Your New Water Heater?

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Original Post: Hot Water Heater Wiring

wildduk Member

I just purchased a new Rheem elec. hot water heater.

50 gallon unit

I need to add a breaker at the box, as well as a disconnect next to the heater.

If I'm reading this right, it says to look at total wattage, which would be 9000, 4500 top/ 4500 bottom, and wire according to their table.

The table is showing a 50 amp breaker and 8 ga wiring.

Am I reading this correct? That seems kinda high. Or should I use the table for just 4500 watts? That would make it a 25 amp breaker and 10 ga wire.

Highlights from the Thread:

ibpooks Forum Topic Moderator

#10-2 wire and a 30A breaker. Only one heating element operates at a time. The load is "continuous" which requires the circuit sized at 125% of the heater load.

AllanJ Member

The name plate or the instructions should state the power requirements, which will take into account one element at a time being powered on.

A few "industrial grade" models will operate both elements at the same time, thus drawing 9000 watts and requiring 8 gauge wiring.

Geochurchi Member

Do you know what code article to refer to? I would follow the mfg. specs.

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