Some key things to think about when buying a disconnect/safety switch are: 

• Whether the unit is new or used
• If the unit is Fusible or Non-Fusible - if it is fusible, does it come with  fuses that are the correct amperage
• Neutral & Ground - Make sure these are included if they are required.  If you need to meet code, you may want to make sure the switch is rated with a neutral.
• Enclosures - Find out if the unit you are buying is the proper enclosure type for the job.  For Example a Nema 1 is an indoor enclosure and a Nema 12 is dustproof, etc.
• Be certain that you are purchasing the proper voltage, phases, and amperage for the application.

• Condition - Although it is typically a safe bet to buy a used disconnect/safety switch, some used units have holes where wire has previously been run in and out of the them and some disconnects will rust.  Just make sure you are familiar with the switch inside and out.

Electrical Surplus Salvage  sells both new and used disconnects/safety switches.  Check out our store!  More photos available upon request!