ground fault circuit interrupters


Old 02-22-05, 07:01 AM
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ground fault circuit interrupters

How difficult is it to install GFCI's in an older (~1970's) home. Can this be done by the home owner or should a professional be called for the job? I am not sure if GFCI are really needed but this is strickly a safety issue as I have two young boys (very active).
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Old 02-22-05, 07:28 AM
Join Date: Sep 2000
Location: United States
Posts: 18,497
If you can follow instructions, you can install a GFCI. There can be a few complications, but you can deal with them. For example
  • If you just have one black wire and one white wire in the box, the installation is simple and trivial.
  • If you have two black wires and two white wires in the box, you'll need a simple $2 neon circuit tester to figure out which pair is the "line" pair.
  • If you find more wires, you may need some wire nuts and pigtails.
Like all electrical projects, it's critical to record what you have to start with before you just start disconnecting things.
Old 02-22-05, 07:36 AM
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
There are several types of GFCI devices available. They all provide GFCI protection, but they all differ in their ease of use and installation.

GFCI circuit breakers. These replace the existing circuit breaker in your panel and provide GFCI protection for an entire circuit. They are available in 120 and 240 volt versions. You must buy the correct model for your circuit breaker panel, and in the correct current rating.

The advantages are that one device protects an entire circuit, regardless of how it is wired, and that they can be used on multiwire circuits. The disadvantages are that you cannot tell the difference between an overload trip and ground fault trip, and that you have to go to the panel to reset the breaker.

These are easily installed if you are familiar with installing and wiring circuit breakers, but are not for the feint of heart, as they require taking the cover off the panel and working near live voltage.

GFCI receptacles. These install in place of regular receptacles. They can be wired to provide protection for the receptacle only, or for any receptacles and other devices that feed from the receptacle (sometimes called downstream devices).

The advantages are that they provide an indication at the receptacle that a fault has occurred, and are reset right there. The disadvantages is that more than one device may be required to provide protection for an entire circuit, depending on the wiring, and that it may be difficult to locate an upstream receptacle that has tripped.

These are fairly easy to install, and come with detailed instructions. It is important to remember to turn the breaker off or remove the fuse before installing any switch or receptacle. When installing, pay attention to the "line" and "load" markings on the receptacle. GFCI receptacles are fairly large, so they don't fit well in crowded or shallow boxes.

They cannot be split, so they will not directly replace a receptacle that is half switched and half always hot, and their use may be tricky on multiwire circuits.

GFCI switches. These can be installed anywhere on a circuit, and provide downstream protection. Since they have no receptacle, nobody will be tempted to plug something in to them.

GFCI extension cords. These are extension cords that have built in GFCI protection. These are point of use only. The advantage is that nothing special needs to be done to the building wiring.

With all GFCI devices, it is important to remember to test them on a regular basis. That regular basis is at least monthly. Most people don't do this, which means that they put themselves at risk if the GFCI protection fails. I test my kitchen and bathroom GFCIs monthly, I test my pool GFCI breaker monthly when on (four months a year), and I test my other GFCIs when I use them.

GFCIs are required in new construction for receptacles serving kitchen counter tops, bathrooms, unfinished basement areas, garages, and outdoors. GFCI protection is also required for swimming pools, hot tubs, spas, and most outdoor devices.

Even without small children, I would still install GFCIs if I were you, in the areas I mentioned. GFCI receptacles are fairly inexpensive ($10 to $12) and not difficult to install.

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