Test Limits for Disconnect Switches

Hello atchet,

Could you be a little more specific please? There are many types of disconnect switches and many more material types that all have unique performance characteristics at the point of contact. In fact, contact resistance is a science of its own, so at this point, it is impossible to give you a meaningful answer.

Please give as much information as you can to avoid silly answers.

Sincerely,

Joe

Have you checked your disconnect switch data sheet as many have the figure for contact resistance on them.

There is no standard contact resistance test limit (it's not a standard test). What's the isolator switch size and application? Is this a maintenance test to check for pitting and arc damage (where the switch is being used outside it's recommended operational range)? Is the disconnect switch for a factory or a children's toy?

Can you provide more information please.

Hello Atchet,

What is your application? Is it a high current high voltage or a low current milli volt application?

Good responses and questions so far. Resistance ranges are typically between fractional milliohms to 100s of milliohms, and will vary with the contacting material, the contact pressure (force over area), the load current and the ability of the physical structure to dissipate heat. Testing with a VOM (applies constant current & measures the voltage drop) having 1 mA or 5 mA will appear to have a higher resistance than passing 5A or 10A through a 5A or 10A rated contact.

Give us a little and you will get a lot!