Is preparing for photovoltaics in new construction sensible?

I’ll pick up the older post:

No, you are not allowed. Actually, for the satellite dish you even need two empty conduits. One for the antenna cables and one for the 16qmm lightning protection conductor. Otherwise, the separation distance according to DIN VDE is not maintained. This is very often done incorrectly in practice.

Primary responsibility for antenna safety lies with the IEC or DIN EN 60728-11 (VDE 0855-1), which unfortunately contains neither a recommendation to route grounding conductors from antennas preferably on the outside nor requires compliance with separation distances calculated according to IEC or DIN EN 62305-3 (VDE 0185-305-3), even though their compliance would be sensible from a lightning protection perspective.

This also applies to photovoltaic cables, which—like antenna grounding conductors—are often routed as lightning conductors through the building with dangerous proximity. A previous rule that grounding conductors for antennas may not be routed together with coaxial cables no longer exists. Lightning that has traveled kilometers from the clouds to the earth can be controlled with HVI cables, but not with a 1 mm cable sheath.

In the current valid version of the standard, it is required that accessible grounding conductors must be installed in a PVC conduit with a 3 mm wall thickness. In the next edition of IEC 60728-11, this passage has been removed.

712.54 Grounding systems, protective conductors, and protective equipotential bonding conductors

If protective equipotential bonding conductors are installed, they must be installed parallel to and in as close contact as possible with the DC and AC cables/wires and accessories.

This standard, responsible for photovoltaic systems, thus explicitly requires that IF a bonding conductor is installed, it must be routed as close as possible to the photovoltaic cables to avoid inductive lightning current coupling from nearby strikes.

CONCLUSION: Anyone who objectively wants to exclude rare direct strikes must have protectable roof installations protected with separate lightning rods according to the state of the art.

Hello everyone,

we are currently in the sample selection phase with our property developer and we would like to prepare our detached house (gable roof 38deg pitch) accordingly for photovoltaic use (see thread^^).

Our house is being built on a slab foundation (without a basement). The utility room is located on the ground floor, and the technical room with air-water heat pump and hot water storage is on the upper floor. The technical room is connected to the utility room on the ground floor by a shaft.

1) Do the photovoltaic modules (inverter, possibly storage, etc.) have to be routed later via the utility room? Do I have to run cables from the upper floor to the ground floor, or can I reasonably combine this on the roof with the heating? I know the question is somewhat unspecific. I myself am not yet exactly sure what we will need. :-/

2) How and where is the "roof penetration" typically realized to bring the cables "into" the house? Is a tile removed and replaced by some kind of conduit? Are the cables from the photovoltaic system (e.g. south side, picture above) routed to the technical room/cable shaft "on" / "in" / "under" the roof? As a result: do I only possibly need to provide an empty conduit in the cable shaft or also have an empty conduit installed within the storey so that the cables can run from the roof penetration to the cable shaft / technical room?

3) FYI: Our property developer charges a hefty €560 for an empty conduit EN40 from the technical room to the utility room. Apparently they are made of gold....

Many greetings and thank you very much for your support.

I'll join in since our photovoltaic system will be installed next Monday.

22 modules; 4x6mm2 for DC and one potential.
If you place that next to an M40 empty conduit, you'll notice that it is more than sufficient.

ad 1 and 2) Even if the inverter were located near the heating system, you would still need an AC cable to the utility room downstairs, meaning a conduit from the attic to the ground floor. If you want backup power (i.e. supply even during a blackout), due to the thick cabling, it makes more than sense to install the inverter and battery in the utility room. Talk to your electrician about ensuring the main electrical panel has enough space reserved for a photovoltaic system.
There should also be roughly 100x100 cm of free space on a wall in the connection room for the inverter plus about 70x30 cm on the floor somewhere for batteries.

Is the electrical main panel located under the technical room near the shaft, and does the latter have inspection flaps at the top and bottom? Then you might be able to lay a conduit yourself (cheapest option), if necessary also a core drill hole next door through the ceiling, which would probably cost about the same... Regarding the roof itself: We had our electrician lay a conduit up to under the roof covering plus 100 cm of loose cable and asked the roofer to later properly route this through the roof covering and seal it at the top with a sleeve (the photovoltaic system came three years later), this cost about 50 euros extra. But we also have a metal roof.

Where the DC cable of the modules passes through the roof covering is secondary, especially if you are covering the entire roof anyway (recommended). The solar installer will wire that for you appropriately; you can then have the cables routed on the roof below the modules. Ideally, the penetration would be directly next to the shaft in the attic.

ad 3) Developer or general contractor? Can you specify the details directly with the electrician or only via the developer/general contractor?

If a conduit is used, make sure to include an internal pull wire. If the conduit has multiple bends, this is worth its weight in gold; otherwise, you can only partially use the diameter (31 mm for a 40 mm conduit). Do you have a satellite dish on the roof? You can share the required equipotential bonding there. You will reasonably need two cables (i.e. 2x2x4 mm²), so one strand for each half of the roof.

If you have any doubts, better take the conduit (and insist on a pull wire!). The general contractor will have chosen the price so that retrofitting would be more expensive for you, meaning their pain threshold for that is already close to being reached. And talk to the roofer (he also has to assume the warranty; if you do it yourself and the roof later leaks, he will try to avoid this liability!).