BEST Location For GFCI ?

[NineInchNails]

I currently do not have GFCI in my 240V circuits and that has been bothering me. I use a 5500W 30A element.

Where is the very best spot to have GFCI? In the breaker box (the origin of this circuit), closest to the electric device itself or does location matter much? In the breaker box would be easiest.

I happen to have a 50A GFCI Spa Panel box. I could swap the 50A breaker for a 30A, plug this box into the wall then plug my controller into this GFCI Spa Panel. I like this idea because the GFCI can be moved, used or not used depending on the situation. If the GFCI is installed in my breaker box then only once 240V circuit would be GFCI protected. I have 2 or 3 240V circuits within my garage. The SAFEST location is my primary goal.

The cheapest 30A GFCI breaker I've found so far is at Home Depot $63.41

[HDNB]

doesn't matter.

in the panel will protect the whole wire. closer will only protect after the GFI breaker.

GFI needs a minimum wire length but it's about 6 inches. going with that thought, longer would be better, since there is a minimum? I can't see a reason for moving or not using a GFI (well, i guess some loads in a shop may not be compatible with a GFI but dunno what) so i'd just hard wire it to a plug and use and extension cord after that. Then everything is protected.


i'm having a reading comprehension problem with your ideas on the 30A breaker though... there is no need for it if you have a 50 GFI.

[NineInchNails]

doesn't matter.

in the panel will protect the whole wire. closer will only protect after the GFI breaker.

GFI needs a minimum wire length but it's about 6 inches. going with that thought, longer would be better, since there is a minimum? I can't see a reason for moving or not using a GFI (well, i guess some loads in a shop may not be compatible with a GFI but dunno what) so i'd just hard wire it to a plug and use and extension cord after that. Then everything is protected.


i'm having a reading comprehension problem with your ideas on the 30A breaker though... there is no need for it if you have a 50 GFI.

I was of the understanding, perhaps incorrectly, that it is best to use a 30A GFCI breaker for a 30A heating element. So it's equally safe to use a 50A GFCI breaker to run a 30A element? If so then I'm good to go.

I use welders in the garage on occasion which shouldn't require GFCI if I'm not mistaken.

[fizzix]

Generally you want your load to be 80% of the breaker capability max.
So 30amps/0.8 = 37.5amp breaker. OK to round up to 40amp breaker.

[NineInchNails]

Generally you want your load to be 80% of the breaker capability max.
So 30amps/0.8 = 37.5amp breaker. OK to round up to 40amp breaker.

So 50A would not be ideal. That's what I figured.

I've always ran my element on a 30A breaker and it has never tripped, nothing warm or hot to my knowledge.

Technically a 240V 5500W element should have a max of 22.91A. That would mean that 22.91 / 0.8 = 28.64A. A 30A breaker should be most appropriate I would assume.

[Expat]

The 80% rule is for max load, you don't want to overload a breaker but under loading is not an issue. The GFCI will trip just the same at 10A as it does at 50A, if a short to ground is detected. It's purpose isn't to limit the load, but to provide ground fault protection.

I'm using a 50A GFCI with my setup next to my still, the breaker feeding the circuit at the box is 30A.

As for placement, I would suggest it should be near to where you're using it, and a minimum of 36" away from any source of water. Reduces the chances if a nuisance trip and can be used as a primary shutoff.

[NineInchNails]

The 80% rule is for max load, you don't want to overload a breaker but under loading is not an issue. The GFCI will trip just the same at 10A as it does at 50A, if a short to ground is detected. It's purpose isn't to limit the load, but to provide ground fault protection.

I'm using a 50A GFCI with my setup next to my still, the breaker feeding the circuit at the box is 30A.

As for placement, I would suggest it should be near to where you're using it, and a minimum of 36" away from any source of water. Reduces the chances if a nuisance trip and can be used as a primary shutoff.

That makes a lot more sense. So you think I should wire my 50A GFCI Spa Panel box with plugs and connect my controller to it?

[HDNB]

think of it this way:

You have a 50mm water line feeding a 30mm faucet. You will have all of the water pressure and volume available at that faucet, that a 30mm faucet can handle.

if you have the slightest leak anywhere before the faucet the GFI will shut off the water instantly. If you break the 30mm faucet and the water gushes out at 50mm the breaker will trip and shut the water off.

sorta anyway...

a panel with a gfi, wired to a receptacle will allow you to plug in a 50A extension cord. That cord, and anything plugged into it will be protected.it will use less parts (therefore cost less) and allow you to plug in more than just a controller and still maintain the gfi * protection. LIke pumps, mills, augers, mixers etc.
*assuming it's all wired correctly

[Expat]

Not knowing the specifics of your gfci, I would just say you should wire it in between your source line and an appropriate outlet to plug your controller into.


Here is what I did, if that helps.

[NineInchNails]

I have 3 wired 240V outlets in my garage and each are wired with the proper gauge wire and 30A breakers. I figured I'd wire my gfci spa pannel with Twistlock plugs. Plug the gfci into the outlet and plug the controller into the gfci.

[Expat]

No reason I can think of why that wouldn't work.

[NineInchNails]

No reason I can think of why that wouldn't work.

Thanks Expat. I have a much better understanding now. I had the misconception that the 50A breaker in the spa panel in some way was inappropriate.

[Expat]

No problem.

As I'm sure you're aware, but just to reiterate for others.... The panel side breaker and feed lines (10 awg minimum) supporting the GFCI must all be rated for 30A or better.