Electrical disconnects and Safety switches can be the same thing. The purpose of both is to disconnect the power to or from the power source or load device for safety or maintenance, http://www.scribd.com/doc/6358296/Basics-Of-Safety-Switches
Safety switches come fusible and non-fusible. Fusible disconnects support the installation of fuses and provide a greater degree of protection for the equipment they are hooked up to. The style of fuses installed depends on the type of equipment you are protecting. Non-fusible safety switches function primarily as an on-off switch for maintenance purposes and are generally backed up by circuit breaker protection between them and the power source.
Safety switches are classified as General (or Light Duty) and Heavy Duty. General duty switches are made primarily for residential and light commercial applications where price is a concerned and the unit will not get a lot of use. Heavy Duty safety switches are used where maximum performance and continuity of service (lots of on-off switching of the unit) are a prime consideration. They are built with heavier contacts and springs in them.
The voltages are 120V, 240V, 480V and 600V, single and three phase AC Current. Some are rated for DC voltage applications. Typical amperages range from 30A to 1200A although you can get larger 1600A switches and above.
For a complete list of available new, used and reconditioned safety switches go to http://bit.ly/eesiDisconnects.