Replace a magnetic contactor 42AF25AF by Furnas / Siemens

[dchou4u]

Recently there is sometimes a loud hum coming from an electrical box above the dropped ceiling in our office. We went up and opened the box and saw that it is a Siemens/Furnas 42AF25AF magnetic contactor. I thnk it controls the 220V fluorescent lighting in the lobby.

Where can I get a replacement and is it easy to swap out myself?

Thanks

[Ralph Mowery]

If you put the number in Google you get about 30 places like this:

You should be able to replace it with just a screwdriver or two. Just be sure you test the power to make sure you cut off the correct breaker feeding it. There may be two breakers. One for the main contacts and another for the coil. That may be for a photo cell that cuts off and on some outside lights instead of the lobby lights you think it does.