Voltage test on PID/SSR

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Psych

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What sort of volts would I see with a voltmeter at the two hots when the SSR is not supposed to be on, but the PID is and it's all plugged in?

My electric setup is suddenly coming together, I'm in the testing phase now than I've got my whole 'box-o-electricity' setup. I've yet to plug it all into my element though. I've got 240v coming in, splitting 120v off to power the PID via a switch, then the two hots are going to a disconnect panel, then down to a dryer plug I've mounted within the box.

I can fire up the PID, everything working great there. I've testing (with a multimeter) the voltage across the two hot lines on the dryer plug exit of my box, 240v.

Good, I thought! However, I had the PID set to 40F and ambient was 72F. My RTD was plugged in and reading fine (72F). Should I see voltage at the terminal end of the box wiring only when the PID tells the SSR to heat things up, or is constant voltage there normal?

I sort of figured it would drop to 0v across the two hots until the PID 'out' turned on and it sent it's magic signal to open the SSR up.

Any advice is appreciated!
 
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Psych

Psych

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Ahh, so this is/could be normal and if I'm confident my wiring is right (which I am) then I should just plug my element in and see if I get heat when supposed to?

Double and triple checked all the wiring from PID to SSR and everything looks great, my disconnect switch works properly, so I guess I'm 'safe'...just curious.
 
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Psych

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Just as a followup here for future help if anyone runs into the same issue, it appears to be normal to get 240 at the hots with no element plugged in! Test run proved that my element does indeed fire up just fine now, no issues, and does indeed turn off when the PID tells it to!

And yes, there's still 240v at the two hots when I check it without the element plugged into them. Go figure.
 

brewfreeordie

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I had the same issue. I knew they passed a little current, but didn't realize they would pass full voltage. I checked, rechecked, pulled apart and checked again, then got to thinking it was a bad SSR. Then started thinking it was a current thing. I feel better about adding the contactors now.

Things you learn. Time to rev it up!
 

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