When did metal water pipe become no longer allowed as the only ground for a house electrical system?

Thursday, August 1, 2019

The 1978 edition of the National Electrical Code (NEC) eliminated the option to ground a home’s electrical system to the water pipes. We still occasionally see the ground wire running to a clamp around a hose faucet for the ground of a very old electrical system that has not been updated. But many times it has been converted to a bonding connection for the water pipe and a ground rod now provides the primary ground. 

    The reason for the rule change was the increasing popularity of PVC and CPVC plastic pipes in the 1970s, which are not electrically conductive. Repairs with the plastic pipe can break the electrical continuity of the ground connection of copper or galvanized steel pipe. Most grounding today is done with a driven metal rod (above) or ufer to foundation steel (below).

    But, while the year that the NEC made this change is easy to define, each local juridiction’s building codes don’t necessarily adopt the latest edition of the NEC immediately. The state of Florida, for example, did not make the 2011 NEC effective until mid-2015. Other jurisdictions have sometimes waited even longer to adopt a newer NEC edition and, to complicate things further, they might make amendments that exclude parts of the newest requirements. So the year when an NEC change is published can be several years before your local building department adopted that edition of the code and began enforcing it.

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Here’s links to a collection of our other blog posts about ELECTRICAL WIRING:

 Which house appliances need a dedicated electrical circuit?

 Can a short circuit cause a high electric bill?

 What is the maximum spacing requirement for securing NM-cable (nonmetallic-sheathed cable)?

 Is it alright to just put wire nuts on the end of unused or abandoned NM-cable or wiring?

 What causes copper wires to turn green or black in an electric panel?  

 What are typical aluminum service entrance wire/cable sizes for the electrical service to a house?

 Why is it unsafe to bond neutral and ground wiring at subpanels?

 Should I get a lightning rod system to protect my house?

 Why is a strain relief clamp necessary for the cord connection to some electric appliances?  

 Does a wire nut connection need to be wrapped with electrical tape?

 What is the minimum clearance of overhead electric service drop wires above a house roof?

 What are the requirements for NM-cables entering an electric panel box?

 What is the color code for NM cable (Romex®) sheathing?

 Why is undersize electric wiring in a house dangerous? 

 What causes flickering or blinking lights in a house?

 Why are old electrical components not always "grandfathered" as acceptable by home inspectors?

 How can I find out the size of the electric service to a house?

 What could cause an extremely high electric bill?

 Can old electrical wiring go bad inside a wall? 

 What is an open electrical splice?

 What are the most common electrical defects found in a home inspection? 

 What is the life expectancy of electrical wiring in a house? 

 What is an "open junction box"? 

 How dangerous is old electrical wiring? 

 What is a ground wire? 

 I heard that aluminum wiring is bad. How do you check for aluminum wiring? 

 What is "knob and tube" wiring?  

    Visit our ELECTRICAL page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles. 

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