How to Wire a House   How to Wire a House

How to wire a GFCI or GFI



There are three topics on this page:

  1)  How to Wire a GFCI or GFI?
  2)  How does a GFCI work?
  3)  Where do I need a GFCI in my House?

 

How to Wire a GFCI or GFI Outlet?

When working with electricity always:

  Turn off the power.
  Test the wires to ensure the power is off.
  Lock out the panel box, so no one can accidentally turn the power back on while you are working.

There are basically two steps for wiring a GFCI

  1)  Wire the GFCI.
 

2)  Ground the GFCI.

NOTE: -Aluminum Wires- If you are using aluminum wires in this situation, it is very important that you use fixtures and/or wire connectors or wire nuts that are UL (Underwriters Laboratories) approved for use with aluminum and copper wires. 

 

  1)  Wire the GFCI.
    Looking at a GFCI, it is important to note that there are two sets of terminals. Line terminals and Load terminals. The Load terminals normally has a yellow sticker that covers the terminals. Notice that the terminals are different colors. One is silver and the other is brass.
    If there are only one set of wires in the box then these are to wired to the Line terminals. The white wire connects to the WHITE terminal (Silver). The black wire connects to the HOT terminal (Brass).
    If two or more sets of wires in the box then you must first determine which set of wires power comes into the box. These are the Line wires and are wired in the line terminals. The other set(s) of wires are to be wire to the Load terminals.
  2)  Ground the GFCI.
    Attach the ground wire (bare copper wire or green wire) to the ground screw of the GFCI. If more than one ground wire is in the box, twist them together along with a pigtail with a wire connector (wire nut) or a crimped connector. Next, attach the pigtail ground wire to the ground screw on the receptacle. If you are using a metal outlet box, make sure a pigtail ground wire is connected to the ground screw on the box.
    NOTE:  Before putting the cover plate on the GFCI, make sure the receptacle is aligned straight vertically before you tighten it down (to be visually pleasing). Also, do not over tighten the screws for the cover plate, as it may crack.

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How does a GFCI Receptacle work?

  What is a GFCI?
  A GFCI (Ground Fault Circuit Interrupter) is designed to shut off the flow of current after detecting a ground fault. A ground fault is the shorting of an electrical device or circuit to ground. By doing so, it protects people from electric shock, as well as prevents some electrical fires.
 
How the GFCI Works
 

A GFCI constantly monitors electricity flowing in a circuit. It monitors the current going to the circuit and the current returning back from the circuit. Both should be the same. It the GFCI detects a difference above a preset threshold the GFCI quickly shuts off power to that circuit.

To illustrate, suppose the hot (ungrounded) wire inside of a toaster touches the metal casing. If you came along later and touched the casing while grounded, current or electricity, would now flow through you (you are getting shocked). The GFCI would detect that the current returning from the toaster is less than the current going to the toaster and would trip before a fatal shock occurred. Thus protecting your life.

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Where do I need a GFCI in my House?

  Bathrooms
 

All receptacles must be GFCI protected. - 210.8(A)(1)

 
Unfinished Basements
 

All receptacles must be GFCI protected, except if not readily accessible. Or a single receptacle or a duplex receptacle for two appliances located within dedicated space for each appliance that, in normal use, is not easily moved from one place to another and that is cord-and-plug connected. Or a receptacle supplying only a permanently installed fire alarm or burglar alarm system. - 210.8(A)(5)

 
Garages
 

All receptacles must be GFCI protected, except ones not readily accessible (such as a ceiling mount receptacle for a garage door opener). Or a single receptacle or a duplex receptacle for two appliances located within dedicated space for each appliance that, in normal use, is not easily moved from one place to another and that is cord-and-plug connected (such as a receptacle behind a fridge).

 
Kitchens
 

All receptacles 15A or 20A 125V that serve countertop surfaces or that are 6’ from the edge of sinks must be GFCI. - 210.8(A)(6) & (7)

 
Outside
 

All receptacles must be GFCI protected, except a dedicated branch circuit, not readily accessible for fixed electric snow melting or deicing equipment. - 210.8(A)(3)

Crawl Spaces
 

All receptacles must be GFCI protected in crawl spaces at or below grade level - 210.8(A)(4)

 
Items that need GFI Protection
 

Jacuzzi

Hot Tub

Swimming Pools

Receptacle Replacement

  Replacement of a non-grounding type receptacle with no ground to a grounding type receptacle. GFCI must be marked ‘No Equipment Ground’.

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