ᐅ Two ovens on one circuit – electrician installed only a single electrical circuit

Hello everyone,

I need your assessment on something that honestly left me speechless.

During our house construction, the electrical installation was done by the builder’s electrician. The oven outlet had initially been simply forgotten and needed to be redone anyway. During the conversation back then, I clearly stated that we planned to install two ovens instead of one – a regular oven with microwave function and a steam oven – and that these obviously each need to be separately protected.

Now that the kitchen is fully installed (including the granite countertop, everything finished), I operated both appliances simultaneously for the first time and the circuit breaker immediately tripped. When I looked in the breaker panel, I saw there was only one “oven” breaker, so apparently both outlets are on the same circuit.

Yes, I know I should have noticed earlier, but unfortunately I didn’t.

From everything I have researched so far (VDE 0100-430 and 0100-520), this is definitely not allowed, because the combined load of both appliances significantly exceeds the permissible continuous load of a 16-A circuit. Can someone with expertise confirm this?

Overload protection	Circuit must not be overloaded by two ovens	VDE 0100-430 (433.1)
Dimensioning	Circuit must match operating current	VDE 0100-520 (523.1)
Separate circuits	Each high-power appliance on its own circuit	DIN 18015-1 (10.1)
Compliance	Violation of VDE = violation of EnWG § 49 para. 2	EnWG

Now I am wondering if the fault clearly lies with the electrician and whether he must correct it at his own cost. Also, I’m interested in who would bear the costs if parts of the kitchen have to be dismantled for the retrofit. And lastly: What is the best way to handle this without the situation escalating into conflict?

I want to clarify this calmly and objectively with the electrician, but honestly, I find it quite incomprehensible – especially since the wiring had to be installed later anyway and it was clear two high-power appliances would be connected.

I look forward to your opinions and experiences.

Best regards
dergert

Hello,

It is undisputed that an oven should have its own circuit breaker. But this here:

dergert schrieb:

In the conversation back then, I clearly stated that we plan to have two ovens instead of one – a regular oven with microwave function and a steam oven – and that these obviously each need to be separately protected.

could become a problem. You said it – do you have any proof of that? Witnesses? If the contractor now says, "I didn’t know about two ovens," it will be difficult.

It’s no use now, but you should ALWAYS put such things in writing… Just to prevent anything from being forgotten.

Another, and probably even bigger problem – what does the contract say? If it only mentions a single oven outlet and you didn’t order a second one as an upgrade from the builder, your position might be very weak. In other words, if you didn’t order it, why would the electrician provide it?

Good luck and best regards,
Andreas

Hello,

Is the circuit breaker a single-pole or a triple-pole breaker? And what is its rating, B16? Which devices are involved (connected single-phase, two-phase, or three-phase, and what is the maximum power for each)?
Is there a cooktop nearby, and how is it connected and protected? Some cooktops only require two phases, so the third phase might be repurposed for an oven.
Does the breaker trip immediately when both devices are on (without heating), or only when both are heating simultaneously?

andimann schrieb:

That won’t help you anymore, but something like this should ALWAYS be done in writing... At least to prevent anything from simply being forgotten.

Hello Andreas, of course I have it in writing. After the verbal discussion, I sent a plan clearly showing that two ovens were planned there.

andimann schrieb:

Another, and probably even bigger problem – what does the contract say? If it only mentions one oven outlet and you didn’t order a second one as a special feature from the builder, your position might be weak. In other words, if you didn’t order it, why should the electrician install it?

The additional outlet was paid for by the builder. The other one I personally ordered from the electrician as an extra request. So that should be fine. Everything was documented and is also stated on the paid invoice. It says “Additional double outlet (separately fused) oven.” As a non-expert, I understand that my requests were taken into account. Retrospectively, it should have said ovens, but I didn’t notice or question that at the time. I mean, they even broke open the wall again for the oven circuit. I would never have thought they would just run a single cable instead of two... Why would they? They definitely knew two ovens were going to be installed.

jehd schrieb:

Is the circuit breaker a single or triple pole? And what rating, B16?

Single, B16.

jehd schrieb:

And what kind of appliances are these (single-phase, two-phase, or three-phase connected, maximum power each)?

I think single-phase, but honestly, I’m not sure.

• Bosch HMG978NB1 approx. 3.6 kW (kilowatts)
• Bosch CSG958DB1 approx. 3.3 kW (kilowatts)

jehd schrieb:

Is there a cooktop nearby, and how is it connected and protected?

The cooktop is on the kitchen island with its own circuit running directly down to the basement -> fuse box.

jehd schrieb:

And does the breaker trip immediately when both ovens are on (without heating) or only when both are heating simultaneously?

No, only when both are heating at the same time. After about 5 minutes it tripped. That’s why I only noticed it today, because this situation hadn’t occurred previously.

Can you say something about the legal situation? Is it considered poor workmanship to connect two ovens to the same circuit like this, and do I have any grounds for claiming remedial work? If it is clear that two ovens are to be installed, isn’t the electrician required to provide a separately protected circuit for each, according to standard industry practice?

Check the electrical plan to see how the outlets are labeled. If both indicate something like "oven," you can argue that it was not installed according to proper standards.

Practically speaking: Do you have additional outlets on the same circuit? Are the refrigerator, appliance outlets, and dishwasher also connected to the same breaker? If not, you could connect the refrigerator to the oven’s breaker and plug the other oven into the refrigerator’s outlet. It’s not an ideal solution, but it might resolve a part of the problem that affects everyday use.

Talk to the electrician; maybe they have an idea for an easy solution.
Everything else is just guesswork. The electrician (hopefully) still knows which cables were routed where—there might even be two cables there or a 5x2.5 cable that was connected incorrectly for some reason, and so on.
Often, different people are involved: one person runs the cables, and weeks later someone else connects everything.
You can’t think as simply as it’s sometimes done on construction sites...

The fact remains that a solution like the one described above—simply connecting the stove to an outlet intended for a different appliance—is not allowed. This becomes problematic if something happens. Insurance companies love that kind of poor workmanship as a reason not to pay when the house burns down.

PS:
The idea that you would get a completely new cable and have them cover all the resulting costs should be rejected right away. I also think a court would consider the effort disproportionate in such a case and seek some kind of compromise.