Replacing an oil-filled transformer is no simple task. Oil-filled transformers have to abide by many requirements from insurance, the National Electric Code, local codes and more, which is understandable considering the high level of risk to people, property and business operations. They require strong engineering expertise to evaluate correct positioning with minimal risk, especially where building combustion is a concern. Many installations require fire-resistant barriers, automatic extinguishing systems and other mechanisms to reduce risk.
There are many different factors that go into transformer replacement - these factors require evaluation from highly trained professionals. Transformer replacement is not an area in which to cut corners. For non-professionals, the best and only way to replace an oil-filled transformer is to work with a team of experts.