Replacing Lead in Wire for Travel Trailer

American Wire Gauge table and AWG Electrical Current Load LimitsThere's a ton of free calculators on the web as well as tables such as the one above.

Is this being run at height(+15ft) as an incoming service? Are you saying the total amperage supply will be 70 A@110v?

I think that you have got something wrong. Is it 35 amps at 12V DC or at 120V AC.

35 A X 2 converters X 10 V = 7.7 KW which is a very large load for a camper. That would keep my house warm in the winter.

What I would do is use two cords, one for each converter. That way if the amount of power for both is not available, then you could run only one converter.

I am guessing that you have 12 V DC at 35 A which is 420 W, so I would guess that an inverter will draw about 650 W. I would look at #12 extension cord per inverter, which is easy to get.

70 A in a camper? Roughing it smoothly Eh? Use the AWG calcs previously mentioned. Make it water resistant, don't forget the 100' voltage drop and, keep someone on watch until confidence is high!

Do not rely solely on the structure for grounding (or 12 V return). Mare sure you have continuous wires of proper gages. It only takes a bit of oxidation to make the structure a bad conductor.