Embodiments herein provide an electrical protection circuit (100) for connecting an Energy Storage Unit, ESU (10) to a main power line (80). The electrical protection circuit (100) comprises first and second main terminals configured to be connected to a main power line, first and second ESU terminals connected to the ESU (10). The first main terminal is connected to the first ESU terminal via a first normally closed, NC, switch (20). The first main terminal is connected to the second main terminal via a normally open, NO switch (40). The first NC switch (20) is configured to be opened thereby to disconnect the ESU (10) from the main power line (80), and the NO switch (40) is configured to be closed thereby to bypass the ESU (10) from the main power line (80) in order to achieve electrical protection for the ESU (10).