What is the ruling on working to install fences around grape farms from which wine is made, and is the money earned from this work unlawful (haram)?

Working in a grape vineyard is not forbidden unless the intention is to produce intoxicants from it. Therefore, there is no harm in working with something that can be used for either lawful or unlawful purposes, as long as one is not certain that it will be used for unlawful purposes. If certainty of its unlawful use is established, then it is not permissible.