Another electrical question for the experts...

I got great answers to my question of the SSR's yesterday, so here is another one...

Trying to finish my all electric herms control box and got to the point of connecting it to my 50 Amp 240 outlet recently installed. After it is plugged in, the breakers return to off immediately. Obviously I have a problem. I have checked the internal wiring of the control box by giving it power separate from my breakers, and it worked fine. I have checked voltage and it appears to be where it should be and not where it shouldn't.

The outlet is fed by 6/4 cable back to my main panel with a 50 Amp breaker. (non GFI). I then plug in a 4 prong 50 Amp plug with 6/4 SO cord which goes to my Spa panel. The spa panel has a 50 Amp GFI 2 pole breaker to feed the 240 V elements and SSR's and a 15 Amp GFI single pole breaker to power the pump, the PID's and the 12 and 24 volt transformers.

The hot legs are kept separate (i.e. the red and black from the 50 Amp GFI breaker are separate from the black hot from the 15 A GFI breaker. All of the neutrals (including the neutral coming from the GFI's) are combined and the grounds are combined.

I feel like my problem is in the Spa panel and the use of the GFI breakers. I wired it this way so that I could both my 120 and 240 V power GFI protected. I read that a single GFI breaker in the main panel will trip if you try to separate it into 120 V and 240 V in the control box due to unequal voltage coming back to the breaker. Anyway, I am wondering if I have inadvertantly created a similar problem.

All help is greatly appreciated as I am itching to brew (especially with the 2 feet of snow on the ground and growing)

Thanks

Bill

I want to preface this by saying be very carful around electricity. I am not an electrician, nor do I assume any responsibility if you burn your house down or electrocute yourself.

You need to keep the neutral conductors separate for each GFI circuit. A GFI works by sensing the total current leaving a breaker on the hot(s) and comparing it to the current returning on the neutral of that same circuit. If you tie all the neutrals together, some current from one breaker flows back through the neutral wires of other circuits, and the breaker senses this as a ground fault and trips.

This way, if you manage to short hot to ground through your body, or your brew, or whatever it's not supposed to go through, the breaker trips and hopefully saves you from death or dismemberment. This is also why its important to ground everything metal in your brew rig. If a heating element somehow leaks and makes your wort 'hot' (electrically, not temperature wise), you want the easiest path to ground to be from your wort to the well grounded keggle sitting on the grounded brew stand, not through the first person to touch the keggle, through the (sort of) grounded concrete floor. That way the breaker trips immediately, and you know something is wrong and can fix it before it becomes dangerous.

Good luck, and be carful.

Don

I'm confused. Exactly which breaker is tripping? If it is the main, non-GFCI, then you have a dead short somewhere. If it is on of the GFCIs, then you either have a dead short or a ground fault.

If it is the GFCIs' I would do like Don said and separate your neutrals. You can't share neutrals with GFCIs, it won't work. That would be your first step.

If your spa breaker has a 240v gfci in it, it probably will support 110 as well. does the breaker in the spa unit have a white pigtail attached to it and the neutral bus?
If so, ditch the 110v gfci. There should be another screw terminal in the middle of the breaker foe the neutral on the load side.
You will run the L1, L2, and N from the load side of the breaker to the brewery (and ground from the ground bus bar too). Do not use the neutral from the neutral bus or it will pop the breaker when using 110V.

Here's a pic to illustrate.

See how there are three terminals on the load side? the middle one is the one for neutral.

Now I've been told by some of my electrician friends that you can expect to have problems with gfci wired in series with each other. I haven't done it so I don't know for sure.

CodeRage said:

If your spa breaker has a 240v gfci in it, it probably will support 110 as well. does the breaker in the spa unit have a white pigtail attached to it and the neutral bus?
If so, ditch the 110v gfci. There should be another screw terminal in the middle of the breaker foe the neutral on the load side.
You will run the L1, L2, and N from the load side of the breaker to the brewery (and ground from the ground bus bar too). Do not use the neutral from the neutral bus or it will pop the breaker when using 110V.

Here's a pic to illustrate.

See how there are three terminals on the load side? the middle one is the one for neutral.

Now I've been told by some of my electrician friends that you can expect to have problems with gfci wired in series with each other. I haven't done it so I don't know for sure.

Click to expand...

If you do wire a 110v circuit off of one leg of the 240v GFI, everything on that needs to be rated for the full 50A of the GFI, which means you can't just put a 15A or 20A edison duplex on there as it's on a 50A breaker. You would have the potential to pull 50 amps through a 15 amp plug, which == FIRE.

If it is indeed the GFI that is tripping, separating your neutrals should fix this. Either way, go back over your circuits with a fine toothed comb and follow your current flow to make sure you don't have something backwards causing a short. If a breaker trips, don't just reset it, find out WHY it tripped in the first place. You probably already know this, but better safe than sorry (or dead)


Hope this helps,
Don

DonD13 said:

If you do wire a 110v circuit off of one leg of the 240v GFI, everything on that needs to be rated for the full 50A of the GFI, which means you can't just put a 15A or 20A edison duplex on there as it's on a 50A breaker. You would have the potential to pull 50 amps through a 15 amp plug, which == FIRE.

...

Hope this helps,
Don

Click to expand...

Good point Don.