Three phase for a resistance load??

The advantage is lighter gauge supply wire and smaller control contactors since you are dividing the load across three wires instead of two with the resulting lower current per wire. You also balance the load across all three power phases in the building as opposed to concentrating the load on only two phases. No other particular advantages.

Pete C.

Exactly.

Looking at the web page you linked to it is obvious to me that the 3-phase kilns are special purpose. They clearly state that they are special order only. I assume they are for use where you only have 3-phase available.

Bill Gill

The advantages Pet mentions are relatively minor in a smallish kiln like this.

The other advantage is much simpler to understand: "because it interfaces with 3 phase power".

Kilns like this are most often situated in light industrial or commercial buildings. Such buildings are usually fed with three phase. Aside from general purpose outlet circuits (and _some_ lighting), the higher power circuits (ones you'd sling 30A at 240V devices on) are virtually all 3 phase (or 2 phase of 3) devices.

Which is why, for example, in large commercial wood working shops, even the smaller tools (eg: a 14" bandsaw with a 1HP motor, which'd normally be on a 15A 120V circuit in a home hobbyist's house) are three phase.