Thermistor?

Hi guys, I have what looks like 2 red thermistor that blew up. They are located between both of my 240v line and my neutral. Can anybody confirm thermistor could be located there and does anybody have a idea why the blew up. How do I know what replacement part to get now that they blew up and that the number is gone.

by Spike009
6 days, 11 hours ago

Can you provide more context? Is this part of some electrical appliance? You can also add a photo.

by mrobbins
6 days, 8 hours ago

Thank you for your answers. After further research, found out that those component are probably MOV varistor. I think that there must be a short some where in my card that increased my neutral voltage causing my mov to blow. I will look into it tomorow.

by Spike009
6 days, 6 hours ago

A MOV, or metal oxide varistor is like a very non linear resistor; high resistance when the voltage across it is low and low resistance when the voltage across it is high. They have a number of uses but are commonly connected across a voltage supply to protect downstream equipment from a transient voltage spike and from your description this is why they were used in you case. If they exploded it's either because you are getting high voltage spikes from a low impedance source in your supply or because they are too low a voltage rating. The voltage rating of a replacement should be greater than the maximum voltage of the supply and keep in mind that for ac supply the maximum is 1.414 times the ac rms voltage. For a varistor I would add an ignorance factor of 15% or 20% over this. These things fail with quite a bang so keep your fingers away when you first energize it.

by Foxx
5 days, 20 hours ago
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