GFCI power cord

[thach1aj]

I was wondering if anyone had any ideas on where i could get a 240V 30 AMP GFCI adapter for a 4 wire power cord? I am building a electric herms system and i need a power cord to power my control panel. Thanks.

Cheers,
Andrew

 

[davis119]

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[keelanc]

I ordered one from these guys for my future electric kettle build. It was about $37 including shipping.
http://hosfelt.com/contents/en-us/d702.html

 

[Duckfoot]

Check out this thread....

 

[carlisle_bob]

I was wondering if anyone had any ideas on where i could get a 240V 30 AMP GFCI adapter for a 4 wire power cord? I am building a electric herms system and i need a power cord to power my control panel. Thanks.

Cheers,
Andrew

Hi

Do you have a four wire plug on the wall or is it three wire? If it's four then you have both neutral and ground. With three one or the other is missing (hopefully neutral). As noted in the other thread, there's no really easy way to do GFCI's at 240V.

Bob

 

[thach1aj]

I havent actually installed a receptacle yet, i was told to power my control panel properly id need a four wire 2 hot, 1 neutral, and 1 ground wire and plug. I know another option would be to install gfci breakers. I open to any ideas or options.

 

[TimpanogosSlim]

Hi

Do you have a four wire plug on the wall or is it three wire? If it's four then you have both neutral and ground. With three one or the other is missing (hopefully neutral). As noted in the other thread, there's no really easy way to do GFCI's at 240V.

Bob

Not saying there is a product you can buy, or that my idea would be up to code, or that i am a qualified EE, but it sounds semi-easy to me.

We're talking about - in north america anyway - two hots, a neutral, and an earth. Hot and neutral come from the pole. Earth is earth - a copper clad steel rod pounded into dirt. Or just your water main.

In NA the hots are strung around the house basically evenly so that you, on average, load both of them equally. They also supply large appliance power.

In essence, we are talking about GFI protection simultaneously on two hots. Conceptually, this would require that you cross-link two 110v gfi circuits such that when one trips, the other gets it's "test" button actuated. You could do that with relays, or active circuitry.

Having skimmed the other thread, i don't see why - and again here i don't know elecrtical code - i don't see why the protected breaker excludes an earth line.

 

[carlisle_bob]

Hi

Well oddly enough I am a EE (go figure ...).

A GCFI works by looking at the current balance between two conductors. What goes out on wire 1 needs to come back on wire 2. If the math does not work out, there must be leakage - nuke the circuit.

There are a couple gotcha's with 220. First is that in this case you have three wires. The math would have to be that what goes out on two comes back on one (or some such thing). A "normal" GCFI does not have enough brains to figure that sort of thing out. The second gotcha is that even if it did, it's not set up to have 220 on the "two wires". It's little brains will fry if you hit them with 220.

Put another way:

I hook up two 110 V GCFI's inside a box. I wire one to hot and neutral on one side of the 220. I wire the other to hot and neutral on the other side of 220. All sounds great so far (and is great so far). If I hook up a 110V load to either one, it's protected just fine. Current out the hot comes back through the neutral and the math works out.

Now I go and hook up a 220V load. Current comes out the hot side of one and goes back in the hot side of the other one. No current in the neutral. Both GCFI's decide that there's leakage (and they are right). They trip out.

Not so easy ...

Bob