Insulated conductors formed using a final reduction step after heat treating

An insulated electrical conductor, comprising:

• an inner electrical conductor;
• an electrical insulator at least partially surrounding the electrical conductor, the electrical insulator comprising mineral insulation;
• and
• an outer electrical conductor at least partially surrounding the electrical insulator;
• wherein the insulated electrical conductor is capable of being coiled around a radius of from about 50 to about 100 times a diameter of the insulated electrical conductor;
• and
• wherein the insulated electrical conductor comprises an initial breakdown voltage, over a substantially continuous length of from about 100 m to about 3000 m, of from about 2400 to about 4750 volts per mm of the electrical insulator thickness at about 700° C. and about 60 Hz.

An insulated electrical conductor, comprising:

• an inner electrical conductor;
• an electrical insulator at least partially surrounding the electrical conductor, the electrical insulator comprising mineral insulation;
• and
• an outer electrical conductor at least partially surrounding the electrical insulator, wherein the outer electrical conductor has a yield strength based on a 0.2% offset of about 120 kpsi;
• wherein the insulated electrical conductor comprises an initial breakdown voltage, over a substantially continuous length of from about 100 m to about 3000 m, of from about 2400 to about 4750 volts per mm of the electrical insulator thickness at about 700° C. and about 60 Hz.

An insulated electrical conductor, comprising:

• an inner electrical conductor;
• an electrical insulator at least partially surrounding the electrical conductor, the electrical insulator comprising mineral insulation;
• and
• an outer electrical conductor at least partially surrounding the electrical insulator, wherein the outer electrical conductor includes a heat treated and cold worked alloy material with a yield strength based on a 0.2% offset of about 50% more than the yield strength of the alloy material in its natural state but at most about 400% of the yield strength of the alloy material in its natural state;
• wherein the insulated electrical conductor comprises an initial breakdown voltage, over a substantially continuous length of from about 100 m to about 3000 m, of from about 2400 to about 4750 volts per mm of the electrical insulator thickness at about 700° C. and about 60 Hz.

A continuous insulated electrical conductor, comprising:

• a continuous inner electrical conductor;
• a continuous electrical insulator at least partially surrounding the continuous electrical conductor, the electrical insulator comprising mineral insulation;
• and
• a continuous outer electrical conductor at least partially surrounding the continuous electrical insulator;
• wherein the insulated electrical conductor comprises an initial breakdown voltage, over a substantially continuous length of from about 100 m to about 3000 m, of from about 2400 to about 4750 volts per mm of the electrical insulator thickness at about 700° C. and about 60 Hz;
• and
• wherein the continuous outer electrical conductor is in a selected partial cold worked state that is intermediate between a post heat treated state and a fully cold worked state.

A system for heating a subsurface formation, comprising:

• an insulated electrical conductor positioned in an opening in the subsurface formation, wherein the insulated electrical conductor comprises:
• an inner electrical conductor;
• an electrical insulator at least partially surrounding the electrical conductor, the electrical insulator comprising mineral insulation;
• and
• an outer electrical conductor at least partially surrounding the electrical insulator;
• wherein the insulated electrical conductor comprises a substantially continuous length of from about 100 m to about 3000 m;
• and
• wherein the insulated electrical conductor comprises an initial breakdown voltage, over the substantially continuous length of from about 100 m to about 3000 m, of from about 2400 to about 4750 volts per mm of the electrical insulator thickness at about 700° C. and about 60 Hz.

A system for heating, comprising:

• an insulated electrical conductor positioned in a tubular, wherein the insulated electrical conductor comprises:
• an inner electrical conductor;
• an electrical insulator at least partially surrounding the electrical conductor, the electrical insulator comprising mineral insulation;
• and
• an outer electrical conductor at least partially surrounding the electrical insulator;
• wherein the insulated electrical conductor comprises a substantially continuous length of from about 100 m to about 3000 m;
• and
• wherein the insulated electrical conductor comprises an initial breakdown voltage, over the substantially continuous length of from about 100 m to about 3000 m, of from about 2400 to about 4750 volts per mm of the electrical insulator thickness at about 700° C. and about 60 Hz.