Auber DIY 50A HERMS Brew Buddy 2 dual pole contactor

[jeffalanmcclain]

I have the BB400H (50A HERMS Brew Buddy 2) from Auber DIY and I ran across a problem with my wiring assumptions when I started using additional neutral lines cascaded. Specifically, I was using a neutral from one of my PUMP outputs to provide neutral for a solenoid valve. I was only seeing it work when I powered on my pump. Odd, I thought, and then I realized that the default wiring for the the Auber shows both the HOT and NEUTRAL wires going through the 32A contactor (see P1 and P2 contactor in image below). Meaning the neutral on the pump is technically "floating" when not engaged, so tying into that was not a good idea (also left the solenoid floating for return path). Anyway, easy enough fix, but I really have never seen a case where the Neutral line is switched as well as the hot and wanted to ask if *anyone* knew why they had wired it this way and if there was some specific "safety" concern on the pumps to want to have this done?

 

[jeffalanmcclain]

...and is it just "it was free because they had a dual pole contactor"? I have never seen this done (even if it was "free") and I've worked as apprentice journeyman electrician, though only on homes, not DIN relay contactors... Just wondering. I've pulled those neutrals out of being "switched" on my wiring setup, but felt like I should ask for "safety" concerns I might be missing (other than "maybe just in case the pumps weren't wired correctly on neutrals to case" for potential grounding issues). For sure it has always felt odd to me that my pumps have NO GROUND line (i.e. they are two prong only pumps). I have wired the cases to the frame, which should ground them just in case they short out...but.... ??

 

[doug293cz]

AFAIK there is no reason to switch a neutral.

If the pumps have neutral wired to case, and you then also wire the case to ground, you are certain to have GFCI tripping issues.

Brew on

 

[RufusBrewer]

I cannot think of an example where switching the hot and neutral would be a problem. Other than "wasting" a set of contacts.

Switching the ground would be unwise.

I guess you could concoct a scenario of switching both hot and neutral would be a good thing. Something like some where some how a hot and neutral got swapped.