ᐅ Underground cable for outdoor electric driveway gate: 3x1.5 mm² or 5x1.5 mm²?

Most motors don’t even have a separate control line, and more than 3.5 kW (4.7 hp) for a gate opener seems highly questionable. It will probably become clear quickly if you ask the installer to provide the technical documentation. Have you planned to integrate it into your home automation system? If so, wouldn’t the plans have already been of interest?

keychain schrieb:
Most motors don’t even have a separate control cable, and anything over 3.5 kW for a gate motor seems highly questionable.

But the control unit next to it might have one.

Just did a bit of googling and skimmed a manual from Hörmann, for example. They specify 3x1.5 mm² (about 5 AWG) for the motor and, for example (!) 6x1.5 mm² (about 5 AWG) as control cables for push buttons of any kind.
So if there is a switch inside the house, this motor would require appropriate control cables running from the house to the motor. Maybe some functions can also be bridged wirelessly.

We have a summer drive; since there is no push button or other external contacts, it operates with 3 wires. With a push button and feedback, even 5 wires are not enough.

I’m not very familiar with gates, but if it works similarly to my awning motor, then two wires are needed to control the open/up/close functions. The phase wire is connected via a switch either to the open or close wire, plus neutral (N) and protective earth (PE). That results in a 4x1.5 cable. Since this is not a standard cable, the manufacturer probably suggests using 5x1.5. This has nothing to do with the motor’s power. Try to get the wiring diagram for the connection.
If that’s the case, you can place the switch at the gate and operate it there by key and/or remote control. Then, from the house, a 3x1.5 cable is sufficient. It only becomes complicated if the changeover switch has to be inside the house.

Or does the motor require three-phase power?

So our driveway gate operates on a single phase power supply, and the control wires for the switches are routed separately from the motor (probably low voltage). The manufacturer is Tousek.