Be sure to remove the useless fuses off the panel first, then make an electrical connection using the copper wire.
Here's what the walkthrough says:
Take off the 4 broken fuses from the top and middle row and place them on the bottom row and middle or top right.
Use the copper wire on 2 of the fuse leads that you want to have power.
Let's repair the laboratory and treatment room; the left and middle fuses of the middle row. See the copper wire connect the 2 holes-leads of each fuse slot.
Pull down the handle to the ON position.
And how it should look:

Then make to go back up the stairs and see if the phone rings. Also check back in the lab and treatment room to see if the lights are on there.