The BP_LevelCablePlacement blueprint allows you to connect devices with cables as the level designer in the engine. To use the this drag the BP_LevelCablePlacement blueprint into the level, this will need to be done for each time you want to connect 2 devices together.

In the example below I will be connecting a car battery and solar panel. Select the BP_LevelCablePlacement blueprint in your level, then in the Details panel click the eye drop tool icon for the start actor and select one of the devices you want to connect the cable to.

Then do the same thing with the End Actor by selecting the eye drop tool icon next to it in the details panel and select the other device. Once done it should look similar to the image below.

Next you need to set the Start Cable Connection Socket and End Cable Connection Socket. For this you need to decide which device is should be outputting power. In my example that will be the BP_SolarPanel. So we need to make sure we get the name of the Output BP_CableConnectionPointComponent and we need to make sure we get the name of an Input BP_CableConnectionPointComponent from the BP_CarBattery.

Once done you can play in editor and a direct cable should connect the 2 devices.

You can also choose the route the cable uses between the devices, this can be done by selecting the Add Cable Point button in the Details panel with the BP_LevelCablePlacement blueprint selected like shown in the video below. Note when moving the location points make sure you select the blue outline shapes like I do in the video and not BP_LevelCablePlacement actor itself.

You can also use the Duplicate Last Cable Point button, this will create a point close to the last point that was created. To remove points you can delete entries from the Cable Points array, you can also manually set exact locations for the cable points here as well.

To remove all the cable points click the trash can icon next to the + icon.