Change the 220v 50 amp breaker to 70 amp on existing wiring to pool panel

240vcircuit breakergaugepool

Currently I have a 50 amp breaker (220v) running to my pool panel. My pool panel has two 110v outlets and a 20 amp (220v) to run my pool pump. I want to add an electric pool heater which will be a 40-60 amp (220v) dedicated circuit that will be added to my pool panel. With that being said, I guess I need to increase the breaker size in my house that goes to my pool panel from 50 amp to 70 amp. So my question is wiring size. I need to make sure the wiring that's existing is the correct gauge for me to increase the breaker size. I dont know exactly what gauge it is but this is what it says on the wire: CSA T90 NYLON OR TWN75 F11 NOM – ANCE 90°C RoHS 600VOLTS VW

I dont know if this is needed but my main breaker in my house is 200 amp. The wiring going to my pool panel is in gray conduit from my breaker panel in my house to my pool panel which is located outside obviously (which I believe is done that way to be up to code). Electrician ran that for me about 7 years ago.

Best Answer

All I am trying to do is answer your basic question. Simplistically put, the NEC requires electrical conductors to be protected by overcurrent protection that matches the current carrying capacity of said conductor. So in your case you must run a #4 for your 70A breaker.

If you are trying to determine a wire size you should be looking for a marking similar to this.

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The reason everyone is asking questions is because we think we could help if we had more information. See comments above.

PS - Instead of a 12 your looking for a #8 or 6 or 4.