RIMS Rocket tripping GFCI Breaker

[xipetotec]

I decided to test my RIMS setup this weekend and ran into some perplexing problems. I've got a Blichmann RIMS Rocket hooked up through a custom PID controller. The 220 comes from a 30 amp GFCI breaker with 3-prong dryer style plugs/extension cords.

Everything seemed OK until I plugged the RIMS rocket into the system, then it would instantly trip the breaker. I thought maybe the problem was with the relay setup I'm using so I took that out of the picture and tried just plugging the heating element straight into the extension cord and had the same problem. I'm fairly certain I have the cord wired correctly, the ground goes to the ground etc. And the rims rocket should be using less than 30 amps according to the docs. Is there something else that could be the culprit? Perhaps the GFCI?

 

[iijakii]

Do you have anything else you can plug into the 220 source to help eliminate it as a problem?

 

[xipetotec]

Good idea. My girlfriend has a kiln that used the outlet previously. I'll ask her about trying that out.

 

[xipetotec]

Bumping this up with new info.

I discovered that the unshielded ground wire from the outlet was hitting the metal breaker box before it went into the GFCI breaker, so solved that part of the problem. But there is a bigger issue I think. After fixing the wire problem the RIMS rocket can be plugged in without tripping the GFCI, however as soon as my microcontroller (or the pumps) are plugged into the 120 outlet they get their power from and I try and energize the RIMS Rocket the GFCI trips. My best guess here is that the pumps (and I'm pretty sure the microcontroler) ground to their connection to the brewstand, which connects the brewstand to the ground on the 120 breaker. The RIMS Rocket also has its metal frame grounded and connects to the brewstand. I'm guessing that this lets the current from the 220 GFCI breaker return to ground via the 120 breaker which trips the GFCI because its assuming that I'm busy being electricuted or something.

This is just my best guess, not sure if that sounds like a reasonable explanation to people who have more knowledge. If it is the case is there anything I can do to solve this apart from somehow rigging the system up so that the 120v pumps and microcontroller get their current from the 220 GFCI breaker?

 

[BrunDog]

Something fishy going on it seems. Got a schematic?

-BD

 

[wzd]

ok, something doesn't add up:

220 comes from a 30 amp GFCI breaker with 3-prong dryer
AND
The RIMS Rocket also has its metal frame grounded and connects to the brewstand

is confusing. A 3 prong has 2 hot and one Neutral and NO GROUND. With a GFCI breaker, connecting the neutral to a ground is a problem and will cause trips. So where is the Rims Rocket frame ground connected?

Ground and Neutral may be connected at the breaker panel, but not anywhere after that and not after an outlet, and especially not after a GFCI outlet.

A couple of options - use the 120 outlet ground for all the frame grounds. and be sure NOT to connect the 220 neutral to ground. Not really recommended but with all GFCI protected stuff, not bad. The preferred option, would be to replace the 3 prong with a 4 prong 220 outlet.

 

[xipetotec]

ok, something doesn't add up:

220 comes from a 30 amp GFCI breaker with 3-prong dryer
AND
The RIMS Rocket also has its metal frame grounded and connects to the brewstand

is confusing. A 3 prong has 2 hot and one Neutral and NO GROUND. With a GFCI breaker, connecting the neutral to a ground is a problem and will cause trips. So where is the Rims Rocket frame ground connected?

Ground and Neutral may be connected at the breaker panel, but not anywhere after that and not after an outlet, and especially not after a GFCI outlet.

A couple of options - use the 120 outlet ground for all the frame grounds. and be sure NOT to connect the 220 neutral to ground. Not really recommended but with all GFCI protected stuff, not bad. The preferred option, would be to replace the 3 prong with a 4 prong 220 outlet.

I'm sorry, when I said grounded with the 220 I meant the neutral line. I'm away from home for the week but I'm almost positive I checked that the metal case of the RIMS Rocket is connected to the neutral of the line, as you're correct, there is no ground on the 3 prong.