New job responsibility imposed by Employer

I work as a Sr. Telecommunications Specialist in the IT dept. where I was hired to do a specific job relating to the company's voice systems and devices, (I'm paid salary, not hourly). In an effort to save money, the company is now requiring me to run and terminate voice and data cabling. I have never done this before nor have I had to do this or seen this done by someone in my position every since I started my career over 12 years ago. I've worked at five companies, and all of them hire outside cabling firms for this type of work. All cabling installers are paid hourly, which is standard per the law. With this new responsibility, it will be around or over 50% of my time and I still need to maintain my other responsibilities, (that I was initially hired for). I'm told if I don't take on this new responsibility that I will be fired for insubordination. My question is: Is this legal and would I qualify for unemployment if I was fired?

I work in Massachusetts.