hotbed overheating

[Shsims]

hey have an I3V that I just upgraded to the 12" from 10" and I'm having an over heat problem with heatbed, 1st j2 relay melted, fixed it, now it looks like wires from headbead are starting to burn and relay may be melting again, what do I need to check, did not have this using 10" bed

[3dkarma]

If the wires from the heat bed are starting to burn then the chances are they're not rated for the current the larger heat bed is drawing. You mention the relay may be melting "again" - does this mean it's melted before? Regardless, if it's melting, it's trying to deal with too much current.