Construction power, which cable is sufficient?

Hello,

we need to cover a distance of 40-50m to our property. An early construction power connection is not feasible time-wise, so we have to pull a cable. Now I wonder if 5x16mm2 is sufficient or if it has to be 5x25mm2. I have searched various sites but am not entirely clear.

We need 1x63A and 2x32A for the construction.

Thank you very much

With us it was similar, for 50m and 2 times around the corner (total about 80m) the general contractor had planned 5x16mm2. A friend who is an electrical engineer recalculated. In our single-family house, sauna, electric stove, huge cooktop, heat pump, electric car preparation, washing machine, dryer, dishwasher, the calculated voltage drop was too high (allowed 2%). His recommendation with reserve was 5x35mm2, when comparing cable prices our decision was 5x50mm2. It's a lot today, but it could look different in 20 years.

Ok thanks, but for us the temporary setup is really only about the construction power, not about the operation for the house. The line will be laid underground by then. We need about 12-16 weeks for this temporary setup :/

With us, the contact person was the electrician from the [GU], who decides what is necessary. If you have to pay for the construction power cable and the house cable, I would only take the second one and then have it rewired.

for us it was similar, for 50m and 2 times around the corner (total about 80m) the general contractor had planned 5x16mm2. A friend who is an electrical engineer recalculated. For our single-family house, sauna, electric stove, huge hob, heat pump, electric car preparation, washing machine, dryer, dishwasher the calculated voltage drop was too high (allowable 2%). His recommendation with reserve 5x35mm2, when comparing cable prices our decision was 5x50mm2.

Sounds to me like a detached desk worker who tried out his textbook knowledge here. Reality and practice diverge exactly at the moment when you have all stove plates, oven, dryer, dishwasher, sauna switched on at the same time in your household and the heat pump running at full load and the e-car charging. In this case the calculated voltage drop would be too high?! And for that you install a bigger cable now? This is really the biggest nonsense I have read in a long time. I hope you deduct the extra cost for the cable from the engineer’s birthday gift budget. I hope he lives long enough to be able to compensate for this unnecessary expense on your part.

Bridging 40-50m to our property.

Now I wonder if 5x16mm2 is sufficient or if it must be 5x25mm2.

We need 1x63A and 2x32A for the construction.

Now back to your question:
The question cannot be answered with the given information.
I assume that the _construction_ requires 63A and 2x32A connections for the construction site distribution boards.
You don't have to assume that all connections will be loaded with the maximum available power. (The electrical engineer in the above example actually overlooked this.)
The question is rather what will be operated with it. For example, if you have a crane, it will get a 32 A connection alone. However, it usually only rarely draws the nominal current. Namely only when it lifts a heavy concrete bucket or similar and simultaneously swivels and moves. And even then it does not draw 32 A but rather about 25 A.
The same applies to all other plugged-in consumers. Very few are operated at full load permanently.
Now you have to consider what you need on your construction site and have a little courage in your assessment.

Example:
Crane: 25 A (but not permanently)
Screed pump 55 A (only for a certain time on site, but then runs for a longer period)
Several construction dryers with 4 A each = 12 A again permanently
Hand machines, circular saws and other gadgets then add another 5 A.

In total that is 25 A + 55 A + 12 A + 5 A = 97 A, so 100 A
Because all of this never runs at the same time, a maximum load of about 80 A can be assumed. This also covers the extreme case where crane and screed pump run simultaneously.

If the cable is not buried, you will do very well with a 5 x 16 mm² cable. That permanently tolerates 85 A and the crane will not run continuously.
For comparison: 25 mm² with the same laying method can handle about 110 A, but you will not need that at a normal construction site.

In your place, I would lay 2 cables with 5 x 6 mm² each. This is usually cheaper than the 16 mm² cable and can carry 92 A in total.

The friendly and competent electrician will of course help you with the execution.