how much energy does a 3Kw oven use?

[isaac3d]

This is a bit like asking how much petrol does a car use. Depends on the car, how its maintained, how its driven, how long the journeys are, where its driven etc.

Just so!
Perhaps a more useful path for the OP to follow would be to choose a method of cooking which is known to be less energy consuming, like a slow cooker for example. As a general guide; the higher the temperature of cooking the more energy is required to maintain that temperature due to increasing rate of heat loss with increasing temperature (unless of course your cooker is perfectly insulated, as in imaginary school physics calculations). Even though a slow cooker is on for longer it works at a much lower temperature with proportionally lower heat loss. The added advantage is that many foods taste better when cooked low and slow.
Have fun experimenting.

 

[Spectric]

This is what a typical 3-phase residential electrical distribution panel in Germany looks like

Looks very well installed compared to what some " electricians" do in the UK. If we started fitting distribution panels that size I think we would lose a room, maybe the so called box room, think of a broom cupboard would suffice.

 

[MikeK]

Looks very well installed compared to what some " electricians" do in the UK. If we started fitting distribution panels that size I think we would lose a room, maybe the so called box room, think of a broom cupboard would suffice.

There is no shortage of cowboy electricians, or otherewise competent electricians who will cut corners if they can get away with it. Before I retired, I had a reputation for being "excessively brutal" on the electrical contractors because I had all of their work supervised by special technicians and made them adhere to the approved schedules, with financial penalties (liquidated damages) for schedule delays.

This distribution panel is in the coat closet with the boiler and hot water storage tank. The panel is 95cm tall, 55cm wide, and 22cm deep (if anyone needs help with the difficult dimension conversion, please let me know). There is a smaller panel available that is the same width and depth, but about 50cm tall. The smaller panel would have worked for my house, but would not have any internal room for expansion and would not have made any difference in the space it occupies, as it's not in the way.

 

[Phil Pascoe]

In millimeters?

 

[Inspector]

So about this tall. , this wide and yeah thick eh?

Pete
Dang the forum software took out the spaces between the hands.

 

[Spectric]

@MikeK So you get three phase and neutral but what is the means of earthing used in Germany? In the Uk with domestic installations we get a lot of protected multiple earthing, PME systems where the supplier only gives live and neutral, the protective earth is derived from the neutral at the consumer end. In industrial applications we get three phase and neutral in the main cable and a separate earth wire is provided as well, using the zinc plated cable armour as the only earth is frowned upon as bad practice.

 

[MikeK]

@MikeK So you get three phase and neutral but what is the means of earthing used in Germany? In the Uk with domestic installations we get a lot of protected multiple earthing, PME systems where the supplier only gives live and neutral, the protective earth is derived from the neutral at the consumer end. In industrial applications we get three phase and neutral in the main cable and a separate earth wire is provided as well, using the zinc plated cable armour as the only earth is frowned upon as bad practice.

@Spectric, great question, and I hope these photos help to answer the question. As a rule, we avoid multiple earthing points.

We bought our house three years after it was built and the previous owner took hundreds of photos during the construction. I was having trouble locating the electrical cables, domestic water pipes, and radiator pipes. As soon as I examined the photos, I was able to trace almost all of the utilities throughout the house. All walls and floors are cast in place reinforced concrete, and the foundation is 50cm (500mm to the challenged) thick. The basement walls are 20cm (figure it out) thick and the upper floors are 15cm thick.

There is only one earthing point, and all other protective earth connections are derived from it. The earth point is a thick zinc plated copper strap that was bonded to the rebar before the concrete for the foundation was placed. When the form work was removed and the interior construction started, the copper strap was bonded to a copper bus attached to the wall at the service entry point. From the bus, all pipes in the immediate area were earthed and the PE cable from the distribution panel on the ground floor was terminated.

In this photo, you can see all of the utilities as they enter the basement below grade, as well as the copper earthing strap. I forgot to label it, but there is a thick gray cable in the upper right of the photo. This is the 3-phase 400V cable from the distribution panel on the ground floor. It will eventually be connected to the black 3-phase 400V input cable.

Here is a closeup of the copper bus with the plastic cover removed. This shows the copper strap and the PE cables after the insulation, screed, and floor tiles have been installed. This is the only earthing point inside the house. The exterior gutter and down spouts are earthed separately with ground rods and straps.

Here is another picture showing the current layout with the PE connections to the water and gas pipes. When we bought the house, we had a whole house water softener installed, so the main water line and sediment filter were rerouted. I also added an untreated water line to the outside of the house (the white pipe that drops and then goes to the right).

 

[johna.clements]

Just so!
Perhaps a more useful path for the OP to follow would be to choose a method of cooking which is known to be less energy consuming, like a slow cooker for example. As a general guide; the higher the temperature of cooking the more energy is required to maintain that temperature due to increasing rate of heat loss with increasing temperature (unless of course your cooker is perfectly insulated, as in imaginary school physics calculations). Even though a slow cooker is on for longer it works at a much lower temperature with proportionally lower heat loss. The added advantage is that many foods taste better when cooked low and slow.
Have fun experimenting.

A the meat on a joint cooked in a slow cooker just falls off the bone.

 

[Inspector]

Mike that seems overdone and a little complex but your country would have its reasons. Here where the service comes into the electrical panel there will be a heavy bare twisted copper ground cable that either goes outside and is clamped to copper grounding rods pounded deep into the soil by the house or down to a buried ground plate down by the footings. The other end to the electrical service panel. All circuits in the house have their own copper grounding wire connected at every receptical that goes to the ground in the panel. Doesn't matter if it is a 110V for lights or a 220V for the stove or dryer, they are grounded. Homes rarely have 3phase power available, just single phase. I'm pretty sure you are familiar with the setup as you lived in the US and it's mostly the same.

Pete

 

[MikeK]

Pete, it does seem to be a bit overboard, but you should see the cable trays and racks in a data center. Every joint in a line of cable trays has a green and yellow jumper connecting each section, even though they are bolted or screwed together. In the racks, each side panel, door, and vertical rail has a green and yellow jumper wire to the chassis.

Yes, houses in the U.S. are grounded as you described. The neutral and ground are bonded at the main distribution panel (a panelboard). When sub panels are added, the neutral and ground are not bonded together at the distant end.

 

[Spectric]

Every joint in a line of cable trays has a green and yellow jumper connecting each section

That is the same here, all conductive metal parts such as cable trays have to be bonded and cannot rely on the fixings holding them together.

Looks like you have just three phase and neutral supplied by the incoming cable and the earth point is at the property, in your case that bonding strap. Much better idea and is how I supplement a PME system.

 

[MikeK]

Looks like you have just three phase and neutral supplied by the incoming cable and the earth point is at the property, in your case that bonding strap. Much better idea and is how I supplement a PME system.

Correct. The incoming black cable from the service provider and the gray cable to the distribution panel are four-conductor cables. Not shown in any of the photos is the junction box where the incoming and main panel cables join. The box is sealed by the provider since the connection is before the meter.

All sub-panels from the main panel use five-conductor cables.

 

[RobinBHM]

I can answer the OP I bought a power meter and have been trying to track down my high power usage (circa 6000KWh pa) in the house. I have been unpleasantly shocked ) ) by many appliances - notably my fridge/freezer (620 Kwh per year) which is quite old. Anyway, the NEFF oven (a relatively expensive one and about 12 years old) pleasantly surprised me. At 180 Fan, it used a tad under 1KWh per hour.

fantastic, that is really helpful -exactly the insight I was looking for

my oven is a John Lewis white labelled jobbie and Its about 10 years old -so could be similar to yours in power usage


what sort of power meter did you buy? -I dont want a smart meter, I just dont trust the energy suppliers.

 

[RobinBHM]

I have heard that turning over off 10 minutes before end of cooking saves energy without making any difference to the cooking.

 

[JimJay]

Here in the Wild East, the neutral and "earth" pins in wall sockets etc are just connected together.....

 

[Spectric]

Correct. The incoming black cable from the service provider and the gray cable to the distribution panel are four-conductor cables.

That is the better way to provide a supply to a property, you are not relying on the provider for a ground connection as it is your responsibility. The big concern with our PME system is that we now have MPDE water and gas pipes so no use for earthing and no guarantee of any other earth unless we fit an earth rod. So now we have a potential situation where if that neutral from the incoming supply becomes open circuit for any reason then power is still supplied to all the loads and because there is no current flow the neutrals are now also live, the neutral and earth are connected at the supply so now unless that earth is grounded it also becomes live, now anything conductive that is earthed is live and just waiting for someone to provide a circuit to ground.