I think you have 2 options:
1. Tough love: Let him cry it out and after a few nights he'll realize that you come back in the morning and that he sleeps by himself downstairs. Will probably take him a week or so to adjust.
2. Crate for safety: Explain to the owner that because he's shown an interest in chewing electric wires that for his own safety it's better for him to be kept away from the wires. That the dog seems to prefer being close to people, so the best way to manage his desire to be nearby and keeping him safely away from wires, is to crate him at night in the bedroom.
1. Tough love: Let him cry it out and after a few nights he'll realize that you come back in the morning and that he sleeps by himself downstairs. Will probably take him a week or so to adjust.
2. Crate for safety: Explain to the owner that because he's shown an interest in chewing electric wires that for his own safety it's better for him to be kept away from the wires. That the dog seems to prefer being close to people, so the best way to manage his desire to be nearby and keeping him safely away from wires, is to crate him at night in the bedroom.