3 wire 2 pole inline gfci for a dryer plug

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  #1  
Old 02-09-12, 02:27 PM
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3 wire 2 pole inline gfci for a dryer plug

Can this

GFCI, Inline, 20 A - Portable GFCI - Ground Fault Protection - 5YL46 : Grainger Industrial Supply

Be wired to work with a 220 4 wire drying plug?
 
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Old 02-09-12, 03:18 PM
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Welcome to the forums! You don't Ground Fault Protect dryers. And, no, it won't work on a 30 amp circuit. Curious, why do you want it?
 
  #3  
Old 02-09-12, 03:47 PM
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I don't want to ground fault the dryer, I just want to use a dryer plug for powering an electric brewery. I'd like to wire up something similar to this. http://www.theelectricbrewery.com/images/GFIplug.jpg

I don't need to draw 30A, 20A will due (3500 watt element ~ 16A). I could install a 30A gfci breaker, but I'd like to have a portable gfci.
 
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Old 02-09-12, 04:41 PM
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The equipment will only draw the amount of current that it is designed to draw, except in the case of a fault. You could (in theory, do not do it!) put it on a 100 amp breaker but it will only still draw 16 amps.

The item you posted from Grainger appears to be rated for what you need (240 volts/20 amps). However, the circuit what you are taping off of has 30 amps available. This means that all the components also need to be rated for 30 amps because of the above mentioned fault would burn it up.

A work around would be to replace the dryer breaker to a 20 amp breaker. This would no longer be sufficient to run a dryer so if you are still using that circuit for the dryer, it could be quite a hassle.

A better idea is to get a 30 amp cord, run that into a small 2 circuit enclosure like this: 60 Amp Indoor Main Lug Surface-LC002GSU at The Home Depot and install a GFCI breaker in it. Then feed your equipment with the proper sized wire based on your breaker size.
 

Last edited by Tolyn Ironhand; 02-09-12 at 05:04 PM.
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Old 02-09-12, 06:19 PM
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@Tolyn
Lost me on running a 30A rated cord to an enclosure. Where would the other end terminate, or plug into. The 30A dryer receptacle???
 
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Old 02-09-12, 06:43 PM
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I don't need to draw 30A, 20A will due (3500 watt element ~ 16A). I could install a 30A gfci breaker, but I'd like to have a portable gfci.
You also can't use a 30A plug and receptacle to serve your appliance. We need more information—like the appliance specs. Also, I can’t tell the plug configuration of your cord, or the cord posted. Do you have a better pic? My point: Buy the appropriate receptacle. And buy the appropriate cord and plug to power your appliance. Note, having a larger gauge cord is fine, but the plug configuration “must” be rated for the appliance. To add, it is a code violation to hardwire and terminate a cord from a portable appliance to an enclosure.
 
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Old 02-09-12, 07:07 PM
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Here is a crude diagram:

Dryer recept---> 30 amp cord---> 2 circuit enclosure w/breaker ---> cord/wire to brewing equipment

You plug in the dryer cord using the manufactures plug end. Wire in the other end to the 2 circuit enclosure with the GFCI breaker. On the load side of the breaker you run whatever wire or cord you need for equipment. If it is a 20 amp breaker, then you run #12. I say "wire" because I'm thinking the enclosure could be attached to the brewing equipment. Then you could just use a chase nipple and some THHN wire.
 
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Old 02-09-12, 08:17 PM
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The item you posted from Grainger appears to be rated for what you need (240 volts/20 amps). However, the circuit what you are taping off of has 30 amps available. This means that all the components also need to be rated for 30 amps because of the above mentioned fault would burn it up.
This confuses me a little. From what I read there, it is dangerous to plug something in that draws less amperage then what the plug is rated for? Aren't light bulbs plugged into 15A sockets even though they draw significantly less than 15A?

Would it be unsafe to plug something like this: Single Outlet GFCI Adapter, 15 Amps, 120V - Portable GFCI - Ground Fault Protection - 5YL43 : Grainger Industrial Supply into a 20A socket?

My other question about the original GFCI I posted is that it is 3 wire, as opposed to 4 wire. Would the ground wire just be bypassed around the GFCI?

Sounds like I'm over my head here, and will stick most likely stick with propane, but now I want to learn what I'm missing.
 
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Old 02-09-12, 09:42 PM
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My other question about the original GFCI I posted is that it is 3 wire, as opposed to 4 wire. Would the ground wire just be bypassed around the GFCI?
The circuit for an electric dryer is not 240 volts it is 120/240 volts. That is why there are four wires. Two hots to provide 240 volts for the dryer's heat element and a neutral used with one hot to provide 120v for the motor and controls. In the case of a 240v heater such as you linked to the neutral probably wouldn't be used so you would just have two hots and a ground, 3 wires.
 
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