Note: some of the items I am posting were written last year, and I intend eventually to have all of my stuff in this blog. It will take time. I invite readers to come back frequently because there will be new material every day.
I was a bit surprised! The house had GFCI receptacles in ALL of its electrical outlets. This was an older house, 54 years, and most of the wiring was two wire cloth covered cable popular in the 30's and 40's often referred to in the trade as"rag wire".
The use of GFCI (Ground Fault Circuit Interrupter) receptacles on two wire circuits does provide protection against dangerous shorts and such things a child sticking a knife in the outlet. It's allowed by the NEC (National Electric Code) and while its not the same as having a third grounding wire...in one way it provides better protection. When there is a short on a three wire circuit the excess current continues to flow but is shunted to ground through the ground wire.
When a GFCI senses a difference in current in the hot and neutral lines, it stops current flow all together. That curious child with the knife is saved.
I've seen GFCI receptacles on two wires before but never on ALL the outlets. The set up in this house was redundant as can be....because only one GFCI is needed to provide protection for each electrical branch line. But think about it. In an old house where there is no map of the wiring grid, it would be expensive just have an electrician figure out which outlets should be GFCI'd. Also, when one trips, it would be confusing to find which outlet needs to be reset. So buy the contractors bulk pack of GFCI's and go about putting them in every outlet. It made sense to the seller (who did it himself), to me, and to my client.
This seller's two year old may never know what lengths his father went to add to his safety.
Many home inspectors are not fond of this approach because they cannot test the GFCI on two wires with the traditional testing equipment. Also, in some situations, depending on how the outlet is wired, the use of the regular electronic test equipment can cause a dangerous shock. In a future letter I'll talk more about testing of 2-wire GFCI's and about the draw backs of this set up for electronic equipment which requires a ground.
It's a good idea to have me inspect your client's old home, especially the wiring. You never know what you will find.
Sincerely,
Home Status Inspection Company
April 2006© Home Status Inspection Company, LLC.
All rights reserved.
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