How Electric Heater Are Manufactured?: Basic
Before Reading this post, I would recommend you to see my post on Electric Heater Working Principle for sake of clarity. In the manufacturing of electric heater, a resistance material, often in the form of wire or strip, is used as resistance wire. This Wire is formed into suitable form, Usually coiled, according to end requirement. This coil wire or resistance material is made to surround by insulating material so that only heat can be passed thru it while insulating it from live current carrying conductor. But here is the trick, we have studied in our high school that a bad conductor of heat is also bad conductor of electricity. So how can the insulation material will hold back the current while allow to heat to pass through it?. Actually a compromise is made so that the material will allow some heat to travel through it, while also allowing some electric current in the form of leakage current to get to the sheath material. But the compromise is made in such a way that it favors heat dissipation. Thus it would be usual to have some leakage current coming out of a heater, even if it is a new one. As time pass by, this leakage current would eventually rise and a time will come when this rise will be exponential. This is the time to replace your electric heater, even if it has not failed.