I've been trying to find more information on how cheaters work but could never come to a definite decision on how many total amps they might pull.

Image In Question: https://imgur.com/a/ppwPhCS

Basically my question comes down to this:

1. In the image below, the sub unit is supplied with a max of 125 Amps. Does the two pole 20 Amp "cheater" supply a maximum of 20 Amps or 40 Amps?

• a) If it supplies a maximum of 40 amps, then wouldn't that mean the total possible Amperage that it could try to pull would be 130 Amps, and thus could try to overdraw power, and would pop the main breaker?
• b) If it supplies a maximum of 20 amps, could I safely swap out one of the 15 amp breakers for a 20 amp breaker, provided the cables used are 12 Gauge?

I've been trying to find more information on how cheaters work but could never come to a definite decision on how many total amps they might pull.

Basically my question comes down to this:

1. In the image above, the sub unit is supplied with a max of 125 Amps. Does the two pole 20 Amp "cheater" supply a maximum of 20 Amps or 40 Amps?

• a) If it supplies a maximum of 40 amps, then wouldn't that mean the total possible Amperage that it could try to pull would be 130 Amps, and thus could try to overdraw power, and would pop the main breaker?
• b) If it supplies a maximum of 20 amps, could I safely swap out one of the 15 amp breakers for a 20 amp breaker, provided the cables used are 12 Gauge?