Thermador Wall Oven / $25 / San Diego
- Thread starter stricklybojack
- Start date
stricklybojack
Well-known member
Wow, nice! On the first one which is the one we had, what is the small knob/dial for? Ours had the timer on left, oven control on right, but not the small knob. Interesting wiring on the second, would that be a 3 phase unit?
TD Ovens
On the older SS oven the small radio type dial is a infinite switch to adjust the intensity of the broiler while broiling.
The 2nd TD double oven is the great Micro-Thermal top oven model CMT-21, the power cable is a standard single phase 120-240 hook-up just like ALL US ovens and electric clothes dryers, How many homes would have 3 phase power to operate an oven any way ?
On the older SS oven the small radio type dial is a infinite switch to adjust the intensity of the broiler while broiling.
The 2nd TD double oven is the great Micro-Thermal top oven model CMT-21, the power cable is a standard single phase 120-240 hook-up just like ALL US ovens and electric clothes dryers, How many homes would have 3 phase power to operate an oven any way ?
Combo, the Miami house was 3 phase, built in 55? It needed different models of A/C which was not easy to find after the Fridig water cooled unit died in the late 80's. Most of the houses I've owned were 3 connector with NO ground as opposed to the newer 3 connector with ground.
kb0nes
Well-known member
3-Wire vs 4-Wire
Cuffs, what you are describing (and what is shown on this oven) is a 3 wire split-phase system. You have two hot wires and a neutral, both the hots are ~120v to the neutral but they are ~240v between one another since the AC waveform is 180 degrees opposed. This is single phase distribution since the opposite hots are derived from a centertapped secondary on a single phase fed transformer. I have never seen a residential home with 3-phase power, but I suppose there could be one somewhere.
Recently they added a 4th wire to the standard 240v AC connection in homes. The 4th wire provides a true ground that doesn't carry any load current. In the 3 wire system the neutral acted as a surrogate ground. In the majority of residential cases the neutral and the ground are bonded in the service panel, so the neutral should be ground potential, but a 4th wire makes for an added safety ground.
Cuffs, what you are describing (and what is shown on this oven) is a 3 wire split-phase system. You have two hot wires and a neutral, both the hots are ~120v to the neutral but they are ~240v between one another since the AC waveform is 180 degrees opposed. This is single phase distribution since the opposite hots are derived from a centertapped secondary on a single phase fed transformer. I have never seen a residential home with 3-phase power, but I suppose there could be one somewhere.
Recently they added a 4th wire to the standard 240v AC connection in homes. The 4th wire provides a true ground that doesn't carry any load current. In the 3 wire system the neutral acted as a surrogate ground. In the majority of residential cases the neutral and the ground are bonded in the service panel, so the neutral should be ground potential, but a 4th wire makes for an added safety ground.
I remember at the high school I attended (built in '66), that the range and dryer receptacles in the home-ec room were all the 4-wire type. They were connected to a 120/208 volt single-phase circuit, which originated in a three-phase panel. Although they could have purchased special models for the 208 volt service, they got standard 120/240 volt appliances. The reason for this is that two local appliance dealers (Frigidaire & GE) provided most of them at no cost, and switched them out every so often. Since they wanted to sell them afterwards, they had to be ones that would work in most homes.
They used 4-wire cords and receptacles because the circuits originated in remote panelboards, rather than in the main service as would be the case in most houses. Even 50 years ago, the code required that the ground be separate from the neutral in that situation. I've also seen ranges and dryers in large homes use the 4-wire configuration, due to being connected to a remote panel. The only place the neutral and equipment ground are allowed to be joined in in the main service entrance.
They used 4-wire cords and receptacles because the circuits originated in remote panelboards, rather than in the main service as would be the case in most houses. Even 50 years ago, the code required that the ground be separate from the neutral in that situation. I've also seen ranges and dryers in large homes use the 4-wire configuration, due to being connected to a remote panel. The only place the neutral and equipment ground are allowed to be joined in in the main service entrance.
ovrphil
Well-known member
Thatcmt-21...nice unit and price. Four wire talk here is nothing I'm familiar with, so interesting read guys.
stricklybojack
Well-known member
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Here are the pics on the second Thermador I posted, before they are taken off Craig's and this wire discussion will be left hanging...
Here are the pics on the second Thermador I posted, before they are taken off Craig's and this wire discussion will be left hanging...
