Meaning of one simbol in schematic

[harp]

please tell me what means simbol with curved arc (like headphones) on shematic? Why is there and can it be omitted?

Also, I wish to build device like that, with isolation transformer and variac, so seek to achieve a expert tip about that, maybe schematic with some genius feature (some switches, lights, etc...) on it that work wery well in practice. I see few videos where sugested only that ground is not connected, nothing else about featured and usefull control.

[stj]

Re: Meaning of one simbol in schematic

it indicates a link between 2 points or a removable connection.
very strange to find it printed on the front of something though.

[redwire]

Re: Meaning of one simbol in schematic

The symbol is for a circuit breaker. So there are two plus a fuse for the variac's protection. I think it's a thermal circuit breaker, so the curved element heats up and pops up.

[stj]

Re: Meaning of one simbol in schematic

i would put a switch on the ground connection.
sometimes it's good, but if you connect something that has an earth-bonded psu then it can partly bypass the isolation

[redwire]

Re: Meaning of one simbol in schematic

With an isolation transformer, do not ground one (output) leg or it defeats the entire purpose of using one, it is no longer isolating pri-sec.
I can't think of when you need to ground an isolation transformer's output.

People misinterpret electrical safety codes which want all (mains) power transformer's secondary grounded to make a neutral.

[eccerr0r]

Re: Meaning of one simbol in schematic

WTF that schematic is really wrong. That has a variable resistor there instead of a true variac... So while that is a circuit breaker, take the schematic with a grain of salt.

[harp]

Re: Meaning of one simbol in schematic

Oh, I forgot all to thank you!