Convert Plug-in to Hard-Wire Connection

My 18 year old 30 gallon electric water heater (240v/3500w) now plugs into a wall receptacle served by a 20a double breaker. The water heater just gave up the ghost and started leaking. The replacement is a similar sized/similar powered unit but code now specifies that the connection should be hard-wired.

Do I just remove the existing plug cover and receptacle, wire nut the new wires into the box, pass them through a metal face plate into bx joined to the face plate, then to the water heater? The service to the water heater is with #12 wire in rigid conduit to a metal box at the wall.

Is that the proper way to convert this setup or is there some other consideration/material to use that make it a proper connection?

Thanks...Stan

Stan
Two things comes to mind here. First is the new water heater a 3500 watt? If it is a 4500 watt water heater the #12 will be to small. Second, is there a disconnect for the water heater within sight and no more than 50 feet away or a lock out on the breaker? If not replace the receptacle with a no fuse disconnect and proceed

Thanks for a quick response

Yeah, the new unit is 3500 watts. The breaker is only 20a with #12 wire, so that is about the max I can put in. Well maybe a 3800 watt unit would be borderline OK. That means that without upgrading the circuit to #10 and a new breaker, I'm stuck with 3500w. The water heater is in a closet on the patio of our townhouse/villa. It is about 5' away from the main panel which is just inside the front door of the villa. There is /no/ disconnect in the closet. I suppose the "disconnect" on the existing water heater was one of those "pull the plug out" styles of disconnect So I guess I will need to use a no fuse disconnect. I'll have to shop for something like that, do you know if it would fit inside the existing box or on top of the existing box?

A plaster ring and a 20amp toggle (light switch) will work great. Using an extension ring on the existing box (assuming it is a 4 square) gives access for the cable to the unit to be attached

Just make sure the switch is a two-pole version (so it can switch both legs), and rated for the load.

That's a nice approach. I was thinking I would have to find a large style of non-fusible disconnect metal box like are used for A/C's. And something like this (appropriately rated/two pole <---Thanks Jim!) would be code-approved by the inspector?

yes .

Great, much thanks...Stan