The technician will connect a power cable as part of the installation process. There are two pieces of equipment you'll need to get your service working on your activation date. Switch your ONT back. If you've spotted a small box on your wall, it's likely to be Openreach equipment. Re: How is my BT ONT box powered as it has no plug? The ONT. However, to answer your question regarding the installation of an Optical Network Terminal (ONT) on the outside of the house and the running of 120VAC to it, typically, the installing company, like Frontier, will follow these usual steps: Power Source: The ONT requires power to operate, and this.