DIY ATO question

[necrio]

Hundreds of hours, thousands of posts. I have read a lot.

A few posts caught my eye though, instead of using a normal extension cord, using the 120v and overloading the little ol' float switch, people used 12v phone chargers or something. Low volts. Low power, directly connected.

http://s17.postimg.org/mvourn3xr/top_off_diagram.jpg

That is what im saying.

Is it fine, or does it still need a relay? Since a relay is really only reducing the 120v to the reduced voltage.
I wired my float switch into a 3.5v air pump, tested. OK! So, the switch is only getting 3.5v, right?

Thanks. I am no electrician, but would love to hear more knowledge on electricity .

 

[SGT_York]

Sorry I cannot see your picture so take these comments with some salty grains.

A relay doesn't reduce current, it uses two circuits the 12V one turns on/off the 120V through the float switches. the 120V powers the pump. The relay is the on/off switch not a transformer or inverter. transformers convert the voltages, inverters change from DC to AC or reverse.

So unless you have a 3.5v pump you must use a relay. If you skip the relay and have a 3.5v pump (not likely in water) you also need to verify that the amp draw on your pump will not exceed the capacity of your switch or the switch will heat up and possibly burn out.

 

[necrio]

I cut the power of a old fashion air pump. Not water. Going with the air driven ato. I'll check the amperage when I get home.

But basically I cut the hot end of the air pump which draws 3.5 watts. Basically like the people do with extension cords. Should I add the relay ?