I have a three wire 220 volt GFI apparatus. I need to attach this to a four wire in and four wire out how do I do this to get the adequate protection?

Question

I have a four wire 220 volt line going to a pier. I have a three wire 220 volt GFI to use to protect this pier how do I hook it up how do I provide the protection? Again how do I wire it up?

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I am new at this so please bear with me the line to the pier is a four line 220 volt. I have a 220 volt three line GFI that I would like to put in but do not know how to hook it up to the four line 220 volt in order to give the required protection. This is what I need help with. Thank you three line 220 GFI is part of a extension cord it is not a breaker it is an extension cord. I tried to put in a 220 GFI circuit breaker but I do not have room in my panel.

Answer 1

GFCI protection is critical at a pier. Based on the description, it sounds like this is:

• Breaker in panel feeding a 4-wire branch circuit
• Circuit terminates in a 3-wire receptacle at the pier, but unknown receptacle type
• 3-wire extension cord with integral GFCI
• Multiple references to 220V. Likely 240V nominal, but the key is "not 120V", meaning hot/hot/neutral/ground (4 wire) and either hot/hot/ground (3-wire, good) or hot/hot/neutral (3-wire, not good). Need more specifics.

The proper setup is one of the following:

• GFCI/breaker in the panel feeding the 4-wire branch circuit. Then any/all receptacles at the pier are protected with no additional GFCI devices needed.
• Regular breaker in the panel feeding a 4-wire subpanel feed. In the subpanel, all circuits protected by GFCI/breaker. More equipment needed but has the advantage of allowing additional circuits - e.g., a convenience 120V receptacle in addition to the primary 240V load.

Using a cord/plug device with an ordinary non-GFCI-protected receptacle is not allowed for a location that requires GFCI, such as a pier (or actually any outdoor receptacle under current code). That's because there is nothing to prevent someone from plugging something else in that does not have its own GFCI device and getting zapped if it falls in the water.

As far as "no room for 240V GFCI/breaker", that may or may not be true. Double-pole GFCI/breakers are not normally available in half-size form factor. But it may be possible to rearrange and/or replace other breakers in the panel to make room for a double-pole GFCI/breaker for the circuit to the pier.

Alternatively, a small subpanel with GFCI/breakers is not that expensive. There are outdoor-rated 6-space subpanels for around $50 or so retail. Add a double-pole backfed, boldted down breaker for the feed from the main panel and a double-pole GFCI/breaker for the 240V receptacle and you're all set - and have two spaces to spare for extras if needed.

One more key piece is the receptacle type. There are a bunch of different 3-wire receptacles available. Some of those (e.g., 10-30) are obsolete, though I suspect the ones that are obsolete are not likely to have cord/plug devices with GFCI in them either. But more specifics are needed to know for sure. Simply being 3-wire 240V going to a 4-wire feed (whether subpanel in between or not) is not necessarily a problem, as many 240V devices do not need neutral.