ᐅ Distribution Cabinet – What Size Is Practical and Recommended?

Hello everyone,

We are about to start the electrical installation work and are wondering what size distribution board we should have.

Our house is 180 sqm (1,937 sq ft), with 2 full floors, an air-to-water heat pump, underfloor heating, and a photovoltaic system with battery storage. Because of this, we probably don’t need a separate meter for the heat pump electricity.

Our electrician initially recommended a four-module distribution board, for the main house and a separate apartment (which we don’t have), the photovoltaic system, and the heat pump electricity (cost: €1,100).

Our solar installer said we only need two modules, for the house and the photovoltaic system (cost: €520). However, I’ve recently read that it’s better to plan for a larger distribution board.

I will definitely consult our electrician again but wanted to hear your thoughts on this.

Thank you very much!

Just a tip: Distribution boards are measured in TEs (terminal elements), not in 2-, 3-, or 4-way units.

So the specifications are unfortunately meaningless.

It is also unclear how many electrical circuits are planned and many other small details...

I believe fields are meant here.

I would not allocate space for a second meter. The photovoltaic system runs through a bi-directional meter, and self-consumption can be measured with a small device mounted on a DIN rail. Generally, very little from the photovoltaic system actually stays in the panel.
A bit of extra space doesn’t hurt, but there’s no need to overdo it unless home automation is planned – in that case, I’d go for the largest panel ;-)

I understand that you mean fields, but they do exist at very different elevations.

Sorry, I do have the quote from the electrician here, but I don’t understand much of it. However, I know that we are supposed to get a Striebel&J cabinet, fully 3/3A 2Z1V7 KS222. It should look like the one in the attached file. Does this help?

In this configuration, there would be 132 modular units (MUs). I would also consider this the absolute minimum.

About 24 MUs are used for possible cable entries and lightning protection, 12 for neutral and protective earth, leaving only 96.

Adding a residual current device (RCD) here and there, and not just the usual two circuits per room but a bit more, means there isn’t much left. It still fits, but it’s tight.

If you want it to be expandable or possibly add some home automation later, I would opt for the next larger size.

Alternatively, a cabinet with these dimensions but two energy meters instead of the outdated 3-point meter slots would gain another section with 84 MUs (if the utility company agrees). After subtracting those that would be lost, there would then be 192 MUs.