Relay spec- max switching voltage and dielectric insulation of contacts

Thread Starter


Joined May 16, 2019
I am finding difficulty in understanding the difference between maximum switching voltage and dielectric insulation of open contacts in a relay.
I am using a relay NC, when the voltage across contact terminals is above 300v, relay coil is activated and contacts would open which means open contacts would have 300v between them. This would go upto 1000v. Should I choose a relay with max switching voltage 1000v or dielectric insulation between open contacts 1000v.
Thanks in advance.


Joined Mar 14, 2008
If you are switching no more than 300V then the relay should have a switching rating of a least that.
The dielectric rating should be more than 1000V