240v switch on one leg?

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ftlstrings

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Hey all, can I safely use a spst 120v switch on one leg of my 240v march pump to switch on/off? I've seen people post both yes and no in various spots and don't want to, um, die.
 
Yes, you can. All the 120v items in my brew panel pulls from one leg on the 220 feed.

Just be sure it's properly sized for the circuit.
 
Let me say this too: I had two electrical guys, one an electrical engineer, looking at this when we designed it on a rolling stand, and they set it up with one leg being switched. This worked for years. Now I'm looking to hard wire something into my house for a brewery and I wanna make sure it's safe for the fam, and during brew day.
 
It is not uncommon to switch one leg of a 240v pump to control it on & off. If the swicth is going to function as a disconnecting means for the pump then you want it to break both legs of power. That being said if your control box that feed the pump has a main power switch or is cord and plug connected you could just as well call that your main disconnecting means.
 
Will it work to switch only one leg/phase? Absolutely. You just have to bear in mind that even when it isn't running the pump is still hot. Would you be working inside the control panel hot anyway? Probably or hopefully not. Is it a better practice to switch all ungrounded (non-neutral) conductors? Yes it is.
 
Depending on the kind of switch your looking at, the price difference between a SPST and DPST is negligible. Just shop smart.
 
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